What's New in the Journals?

The potential for soft toric fitting in contact lens wearers

Young G, Sulley A and Hunt C. Prevalence of astigmatism in relation to soft contact lens fitting. Eye & Contact Lens 2011;37:1 20-25.

The most commonly quoted figure for the proportion of potential soft contact lens wearers requiring astigmatic correction dates back 35 years to a study by Holden. A new study revisits this figure and also provides insights into the proportion of astigmats covered by toric soft lens stocks of varying range.

Researchers reviewed 11,624 spectacle prescriptions from a UK optical retail chain to calculate the prevalence of astigmatism for various thresholds (0.50-2.00DC) by eye and by patient. Age range was limited to 8-70 years to represent those most likely to present for contact lens fitting. Coverage of various prescription ranges was estimated using a subset of patients (n=5,444) with ≥0.75DC in at least one eye. Results showed:

• The prevalence of patients showing ≥0.75 and ≥1.00DC in at least one eye was 47.4% and 31.8% and, in both eyes, 24.1% and 15.0% respectively
• The prevalence of monocular astigmatism ≥0.75 was 23%
• The proportion of eyes showing ≥0.75, ≥1.00, ≥1.50, and ≥2.00DC was 35.7%, 23.4%, 10.8% and 5.6%, respectively
• The prevalence of astigmatism ≥0.75DC was almost double in myopes compared with hyperopes (31.7% vs 15.7%)
• The prevalence of with-the-rule (WTR) astigmatism was marginally higher than against-the-rule (32.9% vs 29.1%);
• The prevalence of ATR was higher than WTR for higher cylinder powers ( (4.8% vs 2.5% for ≥1.75DC)

Using the prevalence data, the authors review the effectiveness of current soft toric lens availability. For example, a stock range of toric soft lenses in sphere powers +6.00 to −9.00D, three cylinder powers, and 18 axes requires nearly 3,000 prescriptions and provides coverage for 90% of astigmats.CLICK HERE FOR THE ABSTRACTCLICK HERE FOR A GUIDE TO SOFT TORIC CONTACT LENS FITTING FROM OUR ESSENTIAL CONTACT LENS PRACTICE SERIESCLICK HERE TO LEARN ABOUT NEW DEVELOPMENTS IN TORIC DESIGN

A special issue on UV and the eye

Fonn D. A special issue on ultraviolet radiation and its effects on the eye. Eye & Contact Lens 2011;37:4 167-272.

Current thinking on UV and its effects on the eye is reviewed in a special themed issue of Eye & Contact Lens: Science and Clinical Practice (July 2011). The issue offers new evidence on the link between UV exposure and ocular diseases and conditions, and on the benefits of UV-blocking contact lenses for eye protection.

An overview by Professor Desmond Fonn, 12 review papers and an original article are included, based on the proceedings of a symposium sponsored by the journal and the Contact Lens Association of Ophthalmologists (CLAO) in September 2010.

The symposium was supported by an educational grant from Johnson & Johnson Vision Care Inc, the issue covers:

• Epidemiology and public health concerns
• UV-induced immunosuppression in the skin and eye
• Ocular effects of ozone depletion and solar UV radiation
• UV phototoxicity to the retina
• Cellular antioxidant response to UV
• UV radiation and the anterior eye
• The role of UV in age-related macular degeneration
• UV and oxidative stress in cataract formation
• UV as a risk factor for cataract and macular degeneration
• Intraocular and crystalline lens protection from UV damage
• UV absorption by contact lenses and significance for the anterior segment
• Does the eye benefit from wearing UV-blocking contact lenses?
• UV-B exposure to the eye and solar altitude 

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Visual demands with handheld smart phones

Bababekova Y, Rosenfield M, Hue JE et al. Font size and viewing distance of handheld smart phone. Optom Vis Sci 2011;88:7 795-797.

The use of smart phones for text messaging, email and internet access is becoming ubiquitous in modern society. A new study of font size and viewing distance for these devices has important implications for optometric assessment and prescribing.

Researchers at the State University of New York conducted two studies to measure font size and viewing distance while subjects used handheld electronic devices. In both studies subjects wore their habitual correction (spectacles or contact lenses). In the first study (n=129, mean age 23 years, range 18-39 years), subjects were asked to view a typical text message on their own phone and to hold the device ‘as if they were about to read a text message’. The second trial was similar except subjects (n=100, mean age 25 years, range 18-40 years) were asked to view a specific web page and adjust the font size so they could read comfortably. Results showed:

• For text messages and internet viewing, the mean font size was 1.1M, ie approximately 8pt (range, 0.7-2.1M) and 0.8M, ie approximately 6pt (range, 0.3-1.4M) respectively (where M acuity is the distance in m at which the letter subtends 5 min of arc). In Snellen fraction, these were 6/19 (range 6/8-6/35) and 6/15 (range 6/6 to 6/28) respectively
• The mean working distance for text messages and internet viewing was 36cm (range 17-58cm) and 32cm (range, 19-60cm) respectively
• In both studies, font size did not vary significantly with working distance

The mean font size for both conditions was comparable with newspaper print, which ranges from 0.8 to 1.2M (6/12-6/18), but some subjects viewed text that was considerably smaller. The mean working distances were closer than the typical near working distance of 40cm for adults when viewing hardcopy text. These close distances place increased demands on both accommodation and vergence, which could exacerbate symptoms, the authors say. Spectacle lens design (especially for presbyopic correction) also needs to facilitate modern visual demands.

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Early treatment for amblyopia is better, researchers confirm

Holmes JM, Lazar EL, Melia BM et al. Effect of age on response to amblyopia treatment in children. Arch Ophthalmol 2011. Published online July 11, 2011. DOI:10.1001/archophthalmol.2011.179.

Younger children with amblyopia respond better to treatment than do their older peers, according to a meta-analysis by researchers in the US.

The Paediatric Eye Disease Investigator Group reviewed individual subject data from four recent randomised amblyopia treatment trials (n=996, ages 3 to <13). Analyses were adjusted for baseline amblyopic eye VA, spherical equivalent refractive error in the amblyopic eye, type of amblyopia, prior amblyopia treatment, study treatment, and protocol. Age was categorised as 3 to <5 years, 5 to <7 years, and 7 to <13 years, and amblyopia as moderate (20/40 to 20/100) or severe (20/125 to 20/400). In all four studies VA in the amblyopic eye was stabilised with spectacles before treatment, which included patching with or without plano lenses, atropine treatment and use of Bangerter filters. Results showed:

• Children from 7 to <13 years of age were significantly less responsive to treatment than were younger age groups for moderate and severe amblyopia
• No difference in treatment response between children aged 3 to <5 years and 5 to <7 years for moderate amblyopia
• Greater response in children aged 3 to <5 years compared with those aged 5 to <7 years for severe amblyopia
• Improvement was greater when the refractive error was less hyperopic

The authors conclude that amblyopia is more responsive to treatment in children younger than 7 years of age. Although the average treatment response is smaller in children aged 7-13 years, some children show a marked response. They say that in other studies even some teenagers had increased VA with treatment. ‘It seems reasonable to offer treatment to even older children (eg through to age 17) because we are currently unable to predict which patients will or will not respond,’ they say.

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Evidence for the importance of the ‘rub and rinse’ step

Zhu H, Bandara MB, Vijay AK et al. Importance of rub and rinse in use of multipurpose contact lens solution. Optom Vis Sci 2011. Published online 23 June. DOI: 10.1097/OPX.0b013e31821bf976

The trend for contact lens care products has been toward fewer and shorter regimen steps but a new study highlights the importance of ‘rub and rinse’ to the efficacy of multipurpose solutions (MPS) with silicone hydrogel (SiH) and conventional lenses.

The study looked at three MPS (OPTI-FREE^® RepleniSH^® , Aquify^® and ReNu^® MultiPlus^®) used with two SiHs (Air Optix^® and ACUVUE^® Advance^®) and a conventional soft lens (ACUVUE^®). Challenge microorganisms were species of Staphylococcus, Pseudomonas, Serratia, Fusarium, Candida and Acanthamoeba. The effect of rub and rinse, rinse-only, or no rub and no rinse on disinfection efficacy was examined for each MPS using the ISO Regimen Test procedure. Lenses were soaked for 4h or 6h according to the labelled minimum disinfection time.

• Greatest MPS efficacy was observed when rub and rinse was performed before disinfection, with each of the microorganisms regardless of lens type
• Rub and rinse followed by soaking resulted in almost complete removal/killing of challenge bacterial strains (average 0 to 0.1 log CFU per lens)
• No rub and no rinse resulted in a greater load of microorganisms remaining on lenses compared with the other regimens
• When rinse-only was performed before disinfection, the MPS containing polyquad (OPTI-FREE^® RepleniSH^® ) generally performed better against bacteria than the solutions containing polyhexamethylene biguanide (PHMB)
• Significantly fewer microorganisms were recovered from ACUVUE^® Advance^® than from other lenses when MPS were used with a rinse-only step

The authors conclude that ‘rub and rinse’ followed by soaking is the most effective regimen and should be recommended for all MPS and all contact lens types. They observe that bacteria may be more loosely bound to the ACUVUE^® Advance^® lens.

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CLICK HERE TO ENCOURAGE COMPLIANCE WITH LENS CARE

 

Drying contact lens storage cases and Acanthameoba

Boost M, Shi G-S and Cho P. Adherence of Acanthamoeba to lens cases and
effects of drying on survival. Optom Vis Sci 2011;88:703–707.

Drying the contact lens storage case with a tissue is known to reduce bacteria biofilm but a new study from Hong Kong shows that drying is also an important step in reducing the risk of Acanthamoeba contamination.

Sixteen new and 16 used cases were rinsed with Acanthamoeba suspensions. Half of each group were dried with tissue and tested for the presence of Acanthamoeba. To examine effects of drying, 42 case wells were scratched to simulate use and half were artificially soiled with bovine serum albumin to simulate protein deposit in a soiled lens case. These cases and a further 21 unused wells were contaminated with Acanthamoeba (105/ml) and then left to dry in a cool, dry environment. Wells from each group were sampled at 0, 2, 4, 6, 8, 12, and 24h and the number of viable Acanthamoeba determined. Results showed:

• Acanthamoeba were more likely to adhere to used than unused lens cases
• Detection of Acanthamoeba in wiped lens cases was 2-log dilutions less than in cases left wet for both new and used lens cases
• Adherence was significantly different between rinse and rinse/dried cases
• Air drying significantly reduced the numbers of viable amoebic cysts and trophozoites and the effect was time dependent
• Survival was significantly higher in used and soiled wells

Drying with tissue after rinsing significantly reduces numbers of adhering Acanthamoeba. These organisms can even adhere to new, unused cases. Air drying reduces viability but some viable cells were present at 24 h in soiled cases, confirming the role of biofilm in protecting organisms from desiccation. The authors also recommend weekly case disinfection in hot water for 10min to remove biofilm.

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A review of toric soft contact lens stabilisation

Edrington TB. A literature review: The impact of rotational stabilization methods on toric soft contact lens performance Cont Lens Anterior Eye 2011;34:3 104-110.

Improved toric soft contact lens designs have increased prescribing of these lenses although more astigmats could potentially be fitted. A review of developments in toric lens design and their impact on performance is therefore timely.

The twin goals of stabilising toric soft lens rotation are to position the cyl at the appropriate axis and to minimise rotation during or after the blink. Methods used are:

• Prism-ballast
• Periballast (or bal-flange)
• Thin zone (also known as double slab-off or dynamic stabilisation)
• Truncation
• Back-surface and front-surface toric

The review compares stabilisation methods, reports on studies of rotational stability in various head and gaze position, and looks at other factors affecting rotation and rotational stability. The role of eyelid anatomy is also discussed.

The authors note that Accelerated Stabilisation Design (ASD) thin-zone lenses are more stable during large versional eye movements, are less affected by gravity and show a more stable rate of reorientation than other designs, as well as having minimal interaction with the lower lid.

They conclude that newer lens designs tend to reduce lens rotation and improve rotational stability. Better reproducibility, more frequent replacement schedules, expanded parameters, high permeability and better wetting characteristics have also contributed to increase success in prescribing toric soft lenses.

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*NEW* Month of birth and refraction in infancy

Deng L and Gwiazda J. Birth season, photoperiod, and infancy refraction. Optom Vis Sci 2011;88:3 383-387.

Although there is consensus that more light exposure at school age reduces the risk of myopia, there is no agreement on the effect of light exposure in infancy on refractive development. A long-term study from the New England College of Optometry investigates the association between birth month/photoperiod and refraction in infancy.

Over 32 years, three experienced optometrists refracted 722 children at 1-3 months using non-cycloplegic near retinoscopy. Refraction data were grouped three ways: by photoperiod, regular season and alternate season. Photoperiod hours were calculated as the mean daylight hours 30 days after each infant's birth and then grouped into quartiles. Birth season was classified as: regular (spring: Mar-May, summer: Jun-Aug, fall: Sep-Nov, and winter: Dec-Feb) or alternate (spring: Feb-Apr, summer: May-Jul, fall: Aug-Oct, and winter: Nov-Jan). Results showed:

• Mean infant age was 2.11±0.55 months and mean spherical equivalent refraction (SER) was 0.61±1.56D
• Nearly all subjects (95%) were Caucasian and half were female
• Children born in the photoperiod group with the most daylight hours had slightly lower refractions than those in the shortest photoperiod group (0.43±1.60D vs 0.87±1.43D)
• n the longest photoperiod group, the percentage of infants with SER ≤−0.25D was significantly higher (28%) than in the shortest photoperiod group (18%)
• Similar patterns were observed using the alternate season classification, with lower mean SER in infants born in summer vs winter, and a higher percentage of SER ≤−0.25D in infants born in summer vs winter
• By regular seasons, mean SERs were similar between summer and winter.

The authors say a small, statistically significant lower refraction was found in infants with the most versus the least daylight soon after birth, suggesting that light might play a small role in the refractive error of newborns. They acknowledge that a limitation of the study is a lack of data on confounding factors such as parental refraction, education and socioeconomic status.

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Meibomian gland dysfunction: a landmark report

The International Workshop on Meibomian Gland Dysfunction. Invest Ophthalmol Vis Sci 2011;52:4 1917-2085.

Meibomian gland dysfunction (MGD) is a leading cause of dry eye disease throughout the world. Although this condition affects the health and well-being of millions of people, to date there has been no global consensus on the definition, classification, diagnosis, or therapy for MGD.
After more than two years of work by over 50 leading clinical and basic research experts, the Tear Film and Ocular Surface Society has published the findings of the International Workshop on Meibomian Gland Dysfunction in Investigative Ophthalmology and Visual Science (March 2011). The aims of the workshop were to:

• Evaluate meibomian gland structure and function in health and disease
• Understand the definition and classification of MGD
• Assess methods of diagnosis, evaluation, and grading of the severity of MGD
• Develop recommendations for the management and therapy of MGD
• Develop appropriate norms of clinical trial design to evaluate pharmaceutical interventions for the treatment of MGD
• Create a summary of recommendations for future research in MGD

Here’s THE VISION CARE INSTITUTE™ guide to the workshop’s key findings:

CLICK HERE FOR A FLASHCARD ON MGD: WHAT IS IT? WHY DOES IT OCCUR AND HOW MAY IT BE TREATED?
CLICK HERE FOR A SUMMARY OF THE WORKSHOP’S MAIN FINDINGS
CLICK HERE FOR HOW TO DIAGNOSE MGD
CLICK HERE FOR HOW TO MANAGE AND TREAT MGD
CLICK HERE FOR THE FULL TABLE OF CONTENTS IN MARCH IOVS

 

More evidence for protective effects of UV-blocking contact lenses

Giblin FJ, Lin L-R, Leverenz VR et al. A Class I (senofilcon A) soft contact lens prevents UVB-induced ocular effects, including cataract, in the rabbit in vivo. Invest Ophthalmol Vis Sci 2011; Published online March 18. DOI: 10.1167/iovs.10-6885.

UVB radiation from sunlight is a known risk factor for human cataract. A new study from the US Eye Research Institute provides more evidence for the ability of a Class I UV-blocking soft contact lens to protect against UVB-induced effects on ocular tissues in an animal model.
Rabbit eyes were exposed to UVB light for 30min (270-360nm, peak at 310nm, 1.7mW/cm2 on the cornea). Eyes were irradiated in the presence of either a UV-blocking senofilcon A contact lens (ACUVUE® OASYS®, Johnson & Johnson Vision Care, absorbing 99% of incident UVB and 90% of UVA), a minimally UV-blocking lotrafilcon A contact lens (Focus Night & Day®, CIBA Vision, absorbing 30% of incident UVB and 15% of UVA), or no contact lens at all. Effects on the cornea and lens were evaluated at various times after exposure. Results showed:

• Eyes irradiated with no contact lens protection showed corneal epithelial cell loss plus lens epithelial cell swelling, vacuole formation, and DNA single-strand breaks, as well as lens anterior subcapsular opacification
• The senofilcon A lens protected nearly completely against the UVB-induced effects, whereas the lotrafilcon A lens showed no protection

The authors say that ACUVUE® OASYS® provided nearly complete protection against UVB-induced damage, despite a UVB dose equivalent to exposing the human cornea and crystalline lens to 16h of sunlight condensed into 30min. They conclude that use of the lens is beneficial for protecting ocular tissues of the rabbit against the harmful effects of UVB light, including photokeratitis and cataract.

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FIND OUT MORE ABOUT UV RADIATION AND THE EYE
READ OUR TIPS FOR COMMUNICATING THE IMPORTANCE OF UV PROTECTION TO PATIENTS
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Fluctuation in VA during soft toric contact lens wear

Chamberlain P, Morgan PB, Moody KJ et al. Fluctuation in visual acuity during soft toric contact lens wear. Optom Vis Sci 2011;88:4 E534-8.

Soft toric contact lens wearers often report variable vision but visual fluctuations are not easily measured clinically. The University of Manchester developed a new chart to quantify changes in visual acuity (VA) that result from lens movement and/or rotational instability on eye movement.

The vision assessment at near (40 cm) for soft toric contact lenses (VANT) chart consists of a central, colour-coded, high-contrast logMAR panel and eight peripheral targets on a white background to fixate on to create versional eye movements of 40˚ diagonally and horizontally and 25˚ vertically.
In the first phase of the study, 10 subjects (20 eyes) wore two toric lens types (ACUVUE® OASYS® for ASTIGMATISM and PureVision® Toric) in random order, and the impact of rapid and delayed eye versions in eight directions of gaze on VANT acuity was investigated. In phase 2, 35 subjects (68 eyes) wore four toric lenses (ACUVUE® OASYS® for ASTIGMATISM, Air Optix® for Astigmatism, Proclear® Toric and PureVision® Toric) in random order using a streamlined protocol. Standard fit assessments and distance VA were also performed. Results showed:

• In the first phase, no difference for change in VA for rapid vs delayed version movements but acuity reduction was greater for diagonal than horizontal/vertical versions
• In phase 2 (using rapid, diagonal versions only), differences for low-contrast distance VA measures between lens types and for both VANT baseline acuity and postversion acuity, with ACUVUE® OASYS® for ASTIGMATISM having slightly better acuity than the other three lenses
• No difference between lens types for magnitude of vision loss (about one line)
• No relationship between vision loss and measured rotational stability

The authors conclude that conventional approaches to measuring VA do not fully replicate the real-world experience of soft toric lens wearers. The VANT chart has shown that VA is reduced immediately after versional eye movements and suggests more dynamic methods of assessing visual performance should be considered.
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Modifiable risk factors for AMD in construction workers

Nolan JM, O’Regan S, O’Regan G et al. Update on modifiable risk factors for age-related macular degeneration. Optometry in Practice 2010;11:4 143-150. 

Age, family history and smoking are established risk factors for age-related macular degeneration (AMD) but there is growing evidence that other factors such as diet, obesity and cumulative exposure to short-wavelength visible light may be involved. A new study among construction workers in Ireland, a group exposed to many of these factors, evaluates their risk for AMD and suggests ways of reducing risk.

The Institute of Vision Research, Waterford collected demographic, lifestyle and health data on 853 subjects (age 34±13 yrs) using a nurse-led screening service. Macular pigment optical density (MPOD) was measured with the MacuScope device (www.macuscope.com) and Sightrisk software (www.sightrisk.com) was used to predict percentage risk of AMD. Among the findings were:

• 97% had no or unknown family history of AMD
• Mean MPOD was 0.46 and predicted risk of AMD at age 70 was 20% compared to 10% in the normal population
• Score for dietary intake of carotenoids was 4.9 compared to a highest possible score of 15.5. Mean body mass index (BMI) was 26
• 18% never wore sunglasses, a further 18% rarely wore them and 33% wore sunglasses only ‘sometimes’
• Increased predicted risk of AMD at age 70 was associated with decreased macular pigment and low dietary intake of carotenoids
• Smokers were at greater predicted risk than both past or non-smokers

 The authors conclude that the average construction worker is at double the risk of predicted AMD compared to the normal population. Smoking cessation, dietary modification and, in some cases, dietary supplementation should be advised for these and other individuals with similar environmental and lifestyle traits.

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READ MORE ABOUT LIFESTYLE AND EYE HEALTH
FIND OUT MORE ABOUT ABOUT MACULAR CAROTENOIDS AND AMD

 

Are ocular symptoms worse with computer use or reading?

Chu C, Rosenfield M, Portello JK et al. A comparison of symptoms after viewing text on a computer screen and hardcopy. Ophthalmic Physiol Opt 2011; 31 29–32.

Ocular symptoms during or related to computer use may include asthenopia, accommodative and vergence difficulties, and dry eye. But are these symptoms specific to computer use or simply due to a sustained near-vision task?
Thirty young (18-31 yrs) subjects wearing their usual vision correction read text aloud either from a desktop computer screen or a printed hardcopy page at 50cm for a continuous 20 min period. Identical text, matched for size and contrast, was used in the two sessions which were 24h apart. Target viewing angle and luminance were also similar. Immediately after completing the task, subjects completed a questionnaire rating the intensity of 10 symptoms (0-10 scale). Results showed:

• Comparing the computer and hardcopy conditions, there were significant differences in median symptom scores for blurred vision during the task and mean symptom score. In both cases, symptoms were worse on computer use
• Other symptom scores, such as for eyestrain, tired eyes, headache, dry eyes, irritated/burning eyes and ocular discomfort, although generally higher with computer use, were not significantly different

The authors use the term computer vision syndrome (CVS) to describe eye and vision problems experienced with computer use. They say symptoms after sustained computer use are significantly worse than those reported after hard copy fixation under similar viewing conditions, and call for better understanding of the physiology underlying CVS to allow practitioners to optimise visual comfort and efficiency.

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Swimming goggles limit contamination of contact lenses

Wu YT, Tran J, Truong M et al. Do swimming goggles limit microbial contamination of contact lenses? Optom Vis Sci 2011;88:4 456-60.

Wearing goggles over contact lenses while swimming is often recommended by eye care professionals but there is little evidence that this limits microbial contamination. Researchers in Australia examined whether goggles are effective and whether the type of lens worn affects contamination rates.
A total of 23 subjects underwent two swimming sessions at an ocean (salt water) pool. Silicone hydrogel (Focus Night and Day, CIBA Vision) or hydrogel lenses (Focus Dailies, CIBA Vision) were inserted before each 30 min session. Subjects used goggles with one eye shield removed to mimic goggled and non-goggled conditions, and kept their eyes open. After each session, lenses were collected for microbial investigation and the type and level of bacterial colonisation compared.

• The range of colony forming units recovered from goggled lenses was 0 to 930 compared with 0 to 1210 on non-goggled lenses
• Most subjects (16/23) had more microorganisms recovered in non-goggled compared with goggled conditions (p=0.03)
• Gram negative organisms were found in three non-goggled lenses
• No significant difference was shown in the number of bacteria isolated from silicone hydrogel and hydrogel lenses, irrespective of wearing goggles
• No association was found between the number of bacteria in water samples taken from the pool and those found on the contact lenses.

The findings suggest goggles offer some protection against bacterial colonisation of contact lenses while swimming and support the recommendation that lens wearers use goggles for swimming. Silicone hydrogels seemed to be no more susceptible to contamination than hydrogels under these test conditions.
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Grading and record-keeping in corneal staining

Efron N, Pritchard N, Kady B et al. How optometrists record corneal staining. Clin Exp Optom 2011;94:1 82-86.

Grading scales for recording and monitoring contact lens complications have been available for many years and a recent study in Australia suggests they are widely used. Part of the study looked at how optometrists record corneal staining, with some revealing results.
An anonymous ‘record-keeping task’ was sent to 756 practitioners comprising a form on which appeared a colour photograph of contact lens solution-induced corneal staining. Next to the photograph was an empty box, in which practitioners were asked: how would you record what you see? They were also asked to indicate the level of severity of the condition at which treatment would be instigated. Completed forms were returned by 228 optometrists, a 30% response rate. Results showed:

• 92% of respondents offered a diagnosis; the most commonly used descriptive terms were ‘superficial punctate keratitis’ (36%) and ‘punctate staining’ (29%)
• Severity and location of staining were noted by 69% and 68% respectively, and 44% assigned a numerical grade. Only 3% stated the grading scale used
• 35% of respondents sketched the eye and 2% said they would photograph it
• 10% noted the eye in which the condition was observed
• Opinions of the level of severity at which treatment should be instigated varied considerably, ranging from ‘any sign of corneal staining’ to ‘grade 4 staining’

The authors observe that although most practitioners made a sensible note of the condition and recorded the location of corneal staining, there were deficiencies in other aspects of record-keeping. Optometric education should reinforce good practice in relation to clinical record-keeping, they say.

CLICK HERE FOR ABSTRACTCLICK HERE TO FIND OUT MORE ABOUT THE USE OF GRADING SCALES

 

Practitioner attitudes to children and contact lenses

Sindt CW and Riley CM. Practitioner attitudes on children and contact lenses. Optometry 2011;82:1 44-45.

Fitting contact lenses to children and teens is a major focus for current research. A new survey of US optometrists offers insights into changing attitudes and fitting practices in relation to children’s vision correction.
The survey was mailed to a random sample of 4,004 American Optometric Association (AOA) members in July 2010. A total of 576 surveys were returned, a response rate of 14%. Among the findings were:

• Almost all respondents (97%) fit contact lens patients under the age of 18
• Optometrists most often prescribed spectacles for children aged 8-9 (51%) and 10-12 (71%) as the primary method of vision correction
• Contact lenses were prescribed as the principal form of correction by 20% of practitioners for children at age 10-12 years, 49% at 13-14 years, and 66% at 15-17 years
• Those who were more likely to fit children with contact lenses than a year ago attributed their change in behaviour to daily disposables (30%), ‘improved contact lens materials’ (23%), requests from the child/parent (19%) or ‘recent research or studies’ (10%)
• Almost all respondents (96%) said that a child’s interest and motivation to wear contact lenses was an important factor in their decision to fit

Based on the survey, the authors recommend that practitioners consider determining factors, replacement schedule and contact lens properties when prescribing contact lenses for children. Demand for contact lenses among younger patients may increase in coming years and optometrists should prepare both themselves and their practices to evaluate more children for contact lens wear.
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Compliance with wearing modality of soft contact lenses

Jansen ME, Chalmers R, Mitchell GL et al. Characterization of patients who report compliant and non-compliant overnight wear of soft contact lenses. Cont Lens Anterior Eye 2011; Published online 21 February. DOI:10.1016/j.clae.2011.01.001

Since extended wear (EW) with soft contact lenses is known to carry an increased risk of infection and inflammation, knowing what type of patients use this modality, whether recommended or not, is especially relevant. The Contact Lens Assessment in Youth (CLAY) group has carried out the first large, post-market study of compliance in overnight wear, at six clinical sites in the US and Canada.
A retrospective review of 3,211 soft contact lens patients with known EW status (aged 8-33 yrs, lens power +8.00 to -12.00D) captured demographic and clinical data from 10,516 visits during 2006-2009. Status was either daily wear (DW), compliant EW (overnight wear of US FDA EW-approved lenses) or non-compliant EW (overnight wear of DW-approved lenses). Among the findings were:

• A total of 808 patients (25% of all patients) reported EW at any visit
• Compared to DW, EW users were more likely to be male (41% vs 36%), college students (42% vs 34%), smokers (8% vs 5%) and wearing silicone hydrogel (SiH) brands (64% vs 43%)
• Probability of EW increased until 20 yrs of age then decreased
• Non-compliant EW was reported by 6% of all wearers (13 hydrogel, 2 SiH brands without EW approval were worn for EW)
• Non-compliant EW was not associated with gender, college status or smoking
• Two-weekly and monthly replacement schedules were less likely to be worn as non-compliant EW than daily disposable lenses
• Other factors significantly related to EW were sphere power and years of wear

Young people (18-25 years), males, smokers, myopes, SiH users and patients with >1 yr of wear were significantly more likely to report EW. The authors say non-compliant EW occurs often in young people and daily disposable lens wearers. Understanding who is likely to use EW and non-compliant EW will help clinicians counsel patients more at risk on best practices with EW.

CLICK HERE FOR THE ABSTRACT

 

Compliance with lens replacement, hygiene and case care in soft contact lens wearers

Hickson-Curran S, Chalmers RL and Riley C. Patient attitudes and behavior regarding hygiene and replacement of soft contact lenses and storage cases. Contact Lens Anterior Eye 2011. Published online 12 January 2011. DOI: 10.1016/j.clae.2010.12.005.

Compliance with lens replacement frequency is known to be an issue in soft contact lens wearers but the number of days that the recommended schedule is exceeded is increasingly seen as important. A new study identifies ‘extreme stretching’ of lens life in some wearers, as well as shortfalls in storage case replacement and cleaning.

Researchers conducted two online, sponsor-masked consumer surveys among soft contact lens wearers in the US. One survey (n=645) questioned 2-weekly and monthly replacement lens wearers about their compliance with lens replacement schedule, the other (n=787) surveyed wearers of reusable lenses (excluding daily disposable wearers) on lens disinfection, storage case hygiene and case replacement. Results from the first survey showed:

• More than half were not compliant with their replacement schedule
• Of those prescribed lenses for monthly replacement (n=197), 37% reported replacing them within 4 weeks and 23% reported extreme stretching (≥8 weeks)
• Of those prescribed lenses for 2-weekly replacement (n=448), 45% reported replacing them within 2 weeks, and 4% reported extreme stretching (≥8 weeks)
• Extreme stretching was significantly more likely in monthly replacement lens wearers than in 2-weekly lens wearers

The second survey revealed:

• Very few wearers always cleaned their lens case (26%) and many either failed to empty solution from the case (25%) or ‘topped up’ (54%)
• Median frequency for case cleaning was 2-3 times per week, while 33% reported cleaning monthly or less often
• Median lens case replacement was every 4-6 months, while 48% reported annual replacement or less often
• Most wearers cleaned their lens case with hot or cold tap water (72%)

The authors say these surveys reveal significant non-compliance with replacement schedule, lens care steps and case hygiene. Lenses prescribed for longer replacement intervals can lead to more extreme stretching of lens life. Wearers are confused about the correct method of cleaning cases and how often to replace them.

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Communicating with the visually impaired

Douglas G, Pavey S, Corcoran C et al. Individuals’ recollections of their experiences in eye clinics and understanding of their eye condition: results from a survey of visually impaired people in Britain. Ophthal Physiol Opt 2010;30:4-757.

Understanding patients’ knowledge and interpretation of their visual impairment has important implications for communicating with them in a sensitive and practical way. The latest surveys of a representative sample of visually impaired adults (registered partially sighted or blind) in the UK shed new light on their communication needs.

The Network 1000 survey was carried out by telephone interview in 2005 (n=1,007). Questions covered a range of topics including the nature of their eye condition, details of other health issues and their experiences in eye clinics. Results showed:

• 11% did not know the name of their eye condition and a further 20% had to be prompted to name the condition
• 70% reported having long-term health problems or other disabilities, and 43% reported having hearing difficulties

In a second survey, in 2006/7 (n=922), participants who had become registered as visually impaired in the previous 8 years (n=395) were asked questions about non-medical information received in the eye clinic around that time.

• 17% reported not receiving any non-medical information
• 70% were satisfied with the information received although those of working age were less likely to be satisfied than those of retirement age (56% vs 72%)
• Those who recalled receiving additional non-medical information and advice at registration also recalled their experiences more positively

The authors highlight two key issues from their findings: the importance of the way that the medical condition is communicated and the provision of a broad range of information in addition to clear details about the condition.

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Peripheral refraction differs with ethnicity

Kang P, Gifford P, McNamara P et al. Peripheral refraction in different ethnicities. Invest Ophthalmol Vis Sci 2010;51:6059-6065.

Peripheral refraction has seen a surge in interest following the discovery that peripheral retinal defocus influences the development of central refraction.

Because of differences in prevalence of myopia in white and East Asian populations, Australian researchers compared peripheral refraction along the horizontal meridian in white and East Asian young adults with emmetropic, low myopic, and moderately myopic refractive errors.

Thirty-five white and 37 East Asian subjects aged 18-38 years were divided into three groups: emmetropes (+1.00DS to -0.49DS spherical equivalent), low myopes (−0.50DS to −2.49DS) and moderate myopes (−2.50DS to -5.50DS). Central and peripheral noncycloplegic autorefraction was measured along the horizontal meridian at 5° intervals up to ±35°, and corneal topography quantified.

Results showed:

• No significant differences between whites and East Asians in peripheral refraction profiles in emmetropes and low myopes
• East Asian moderate myopes had significantly more relative peripheral hyperopia than did whites of similar central refractive error
• Corneal shape and power in white and East Asian subjects were comparable

The authors conclude that moderately myopic East Asians have a greater degree of relative peripheral hyperopia and hence a more prolate ocular shape than do white subjects of similar central refractive error. Differences in ocular shape may play a role in the greater propensity for East Asians to develop and progress in myopia compared with whites.

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Prevalence of eye disease in early childhood

Cumberland PM, Pathai S, Rahi JS et al. Prevalence of eye disease in early childhood and associated factors: findings from the Millennium Cohort Study. Ophthalmology 2010;117:2184-2190.

Any eye research involving nearly 15,000 subjects is worth a look and the latest publication from the Millennnium Cohort Study of children born in the UK in 2000 is no exception.

The study collected data on demographic, socioeconomic, and maternal and child health factors for 14,981 children aged 3 years. Maternal reports of diagnosed eye problems were recorded. Risk ratios of the association of eye disease (with or without visual impairment) with socioeconomic and early life factors were calculated. Findings included:

• 5.7% of children had ≥1 eye condition with 0.24% reported to have associated visual impairment. Strabismus and refractive error were the most common
• In the majority, time of onset was reported to be the first year of life
• Eye disorders without visual impairment were associated with lower socioeconomic status, decreasing birth weight, and prematurity
• Visual impairment was more likely in those of low birthweight and from an ethnic minority group, whereas maternal illnesses during pregnancy and white ethnicity were associated with eye disease without visual impairment

The authors conclude that parental reporting can provide useful estimates of the prevalence of eye diseases. They say that the association of parentally reported childhood eye disease with early life factors such as prematurity, ethnicity and maternal ill-health warrants further investigation.

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Psychosocial impact of visual impairment in working-age adults

Nyman SR, Gosney MA and Victor CR. Psychosocial impact of visual impairment in working-age adults. Br J Ophthalmol 2010;94:1427-1431.

It may be intuitive that visual impairment adversely affects the psychosocial well-being of working-age adults but a recent review of the literature in this area provides evidence for these effects.

Researchers at the University of Reading and Royal Berkshire NHS Foundation Trust identified 42 quantitative studies published in English from 2001 to 2008. The studies measured depression/mental health, anxiety, quality of life, social functioning or perceived social support in adults aged 18-59 years. Analysis covered 29 studies that measured one or more of the outcomes, involving a total of 27,842 participants.

Working-age adults with visual impairment were more likely to report lower levels of:

• Mental health (mean difference, MD=14.51/100)
• Social functioning (MD=11.55/100)
• Quality of life (such as those with bilateral visual impairment being 4X more likely to report ‘not feeling full of life’)

Studies into the prevalence of depressive symptoms produced inconsistent results.
The authors say research is needed into the prevalence of loneliness, anxiety and depression in adults with visual impairment, and to evaluate the effectiveness of interventions such as counselling, peer-support and employment programmes.

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Long-term effects of a modern silicone hydrogel contact lens

Guillon M and Maissa C. Long-term effects of the extended wear of senofilcon A silicone hydrogel contact lenses on ocular tissues. Optometry 2010;81:671-679.

Guillon M and Maissa C. Long-term effects of the daily wear of senofilcon A silicone hydrogel contact lenses on corneal and conjunctival tissues. Optometry 2010;81:680-687.

Many studies have described the ocular physiology benefits of silicone hydrogel (SiH) contact lenses over hydrogel lenses. Two new UK studies have now looked at the longer term effects of a SiH lens in both daily and extended wear.

Both studies involved subjects wearing senofilcon A lenses (ACUVUE® Oasys™ with Hydraclear™ Plus) for 2 years. In one study subjects wore the lenses for up to 6 nights without removal and weekly replacement (n=60), and in the second study for daily wear and two-weekly replacement (n=90). In the extended wear study, most subjects were successful existing daily wear hydrogel lens users. In the daily wear study, 64% were current daily wear soft lens users (all types) and 36% were non-wearers. For daily wear, each subject used one of four care systems: three multipurpose and a one-step peroxide solution.

At two years, the extended wear study showed:

• Similar limbal and lower bulbar conjunctival hyperaemia to baseline
• Lower dehydration bulbar staining than baseline, as shown by a decreased incidence of mild or greater staining from 46% of eyes to none
• Lower maximum corneal staining with no staining observed in 68% of eyes at the two-year visit vs 41% of eyes at baseline
• 57% of subjects completed two years’ wear and only 5% of those who dropped out did so for lens-related reasons

And the daily wear study showed:

• For new wearers, no change in the limbal zone and significant improvement in the bulbar area, in terms of hyperaemia and staining, and in corneal staining.
• For established lens wearers, an improvement in all three characteristics
• Lens performance was not significantly affected by lens care system used
• The level of discontinuations was low (29%) compared with other studies lasting over a year that involve frequent follow-up visits, and only four subjects dropped out due to lens-related reasons.

The authors conclude that senofilcon A lenses show excellent biocompatibility in both modalities and maintain excellent long-term ocular tissue tolerance. Used in either modality, these lenses result in less effect on ocular tissue than daily wear hydrogel lenses. In new wearers using the lenses for daily wear, the limbal region was unchanged – an important clinical performance criterion – and both the bulbar region and cornea improved.

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Glaucoma linked with many general health conditions

Lin H-C, Chien C-W, Hu C-C et al. Comparison of comorbid conditions between open-angle glaucoma patients and a control cohort: a case-control study. Ophthalmology 2010;117:2088-2095.

A recent large-scale study from Taiwan provides useful information on the link between general health and open-angle glaucoma (OAG).

The retrospective, case-control study looked at 76,673 diagnosed OAG patients from the Taiwan National Health Insurance Research Database and a comparison group of 230,019 subjects matched for age, gender, urbanisation level, and monthly income. The OAG group had received anti-glaucoma medication or surgery. In total, 31 medical comorbidities were selected and data analysed to estimate the adjusted odds ratio (OR) for each comorbidity between patients with and without OAG.

• Half of the OAG patients (50.5%) had hypertension, and more than 30% had hyperlipidemia or diabetes (30.5% and 30.2% respectively)
• Prevalences of 28 of 31 comorbidities were significantly higher for OAG patients than subjects without glaucoma after adjusting for age, gender, urbanisation level, and monthly income
• Adjusted odds ratio was >1.50 for hypertension, hyperlipidemia, systemic lupus erythematosus, diabetes, hypothyroidism, fluid and electrolyte disorders, depression, and psychosis
• Prevalence difference between OAG and control groups was 3% or more for hypertension, hyperlipidemia, stroke, diabetes, liver disease, and peptic ulcer

The authors conclude that OAG glaucoma patients are significantly more likely to have comorbidities, many of which can be life threatening or affect quality of life.

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‘Rub and rinse’ and corneal staining in contact lens wear

Peterson R, Fonn D, Wood CA et al. Impact of a rub and rinse on solution-induced corneal staining. Optom Vis Sci 2010;87:12 1030-1036.

Corneal staining in contact lens wear has been the subject of much debate, particularly in relation to solution-lens interactions. This study reports a new finding on the impact of a rub and rinse step on solution-induced corneal staining (SICS).

Twenty participants were recruited for two visits, where balafilcon-A lenses (PureVision, Bausch & Lomb) were worn for 2h. One lens was transferred from the blister pack directly into a storage case containing a PHMB-based MPS (ReNu MultiPlus, Bausch & Lomb). The other was rubbed and rinsed with the MPS for either 60s (visit 1) or 20s (visit 2). Both lenses were then soaked in the solution overnight. After recording baseline SICS, the lenses were inserted. After 2h, lenses were removed, SICS was regraded and comfort scores taken. Results showed:

• In every wearer, at both visits, there was less SICS in the eye wearing the lens that was rubbed and rinsed than in the eye without treatment
• In 80% of subjects, the non-rubbed and rinsed lens induced clinically relevant staining, compared to <15% with rubbed and rinsed lenses
• There was no difference in staining between the 60s and 20s rub and rinse
• Comfort scores did not differ between eyes, either on insertion or at 2h

The authors say that SICS observed at 2h of lens wear with this lens/solution combination is significantly reduced by rubbing and rinsing before overnight lens disinfection. Constituents in the packaging solution may play a role in SICS initiation but are unlikely to be the main contributing factor. SICS is most likely related to an interaction of the lens surface with the MPS and tears. Further work is required to establish the longevity of this effect during the monthly wearing cycle.

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Perceived compliance and patient behaviour in contact lens wear

Bui TH, Cavanagh HD and Robertson DM. Patient compliance during contact lens wear: perceptions, awareness and behavior. Eye & Contact Lens 2010;36:6 334-339.

Only one in three contact lens wearers who perceive themselves as compliant with lens care practices actually are, according to a study from the University of Texas.

Researchers evaluated 162 established contact lens wearers after their routine contact lens examination in the university clinic. Each patient was questioned by a single trained interviewer on his or her lens care practices and knowledge of risk factors associated with lens wear. Actual compliance was scored against 10 correct behaviours, and grouped as good, average or poor. Results showed:

• 86% of patients believed they were compliant with lens wear and care practices and 14% identified themselves as noncompliant
• For actual compliance, 32% scored as good, 44% average and 24% poor
• Only 34% of patients who perceived themselves as compliant showed good compliance
• 80% of patients reported an awareness of risk factors, but awareness did not influence negative behaviour
• Behaviours patients did not associate with compliance included swimming in their lenses, topping up solutions, use of tap water and not replacing cases

The authors conclude that perceived compliance is not an indicator for appropriate patient behaviour. A large proportion of patients remain noncompliant despite awareness of risk. They say education alone is not a sufficient strategy to improve behaviour and different approaches aimed at improving compliance with lens care practices are urgently needed.

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Presbyopic correction and night driving performance

Chu BS, Wood JM and Collins MJ. The effect of presbyopic vision correction on nighttime driving performance. Invest Ophthamol Vis Sci 2010;51:4861-4866.

Night driving is one of the most demanding visual tasks yet few studies have examined the impact of presbyopia on driving performance at night. Researchers in Australia used a closed-road circuit to investigate effect of various presbyopic vision corrections on nighttime driving.

Participants were 11 presbyopes aged 45-64 years with a range of refractive errors who previously wore only reading spectacles. Their night driving was assessed while wearing each of four power-matched corrections: single-vision distance lenses (SV), progressive-addition spectacle lenses (PAL), monovision contact lenses (MV), and multifocal contact lenses (MTF CL). Results showed:

• Street sign legibility distances were shorter when wearing MTF CL (38m) and MV (48m) than with SV and PAL (60m)
• Participants drove more slowly with MTF CL than with PALs
• Wearing SV resulted in more errors, and in more and longer fixations, when responding to near targets (simulated radio and speedometer)
• Fixation duration was longer for viewing distance signs with MTF CL than PAL
• No significant differences in road sign recognition, road hazard recognition and avoidance, or lane keeping

The authors conclude that presbyopic vision corrections worn by unadapted wearers affected nighttime driving. Overall, the multifocal contact lens tested (a simultaneous vision centre-near design) affected more of the driving performance measures.
Spectacles performed well for distance driving tasks, but single vision spectacles negatively affected viewing near dashboard targets.

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Do aspheric soft contact lenses improve visual performance?

Lindskoog Pettersson A, Mårtensson L, Salkic J et al. Spherical aberration in relation to visual performance in contact lens wear. Contact Lens Anterior Eye 2010. Published online 6 October 2010. DOI: 10.1016/j.clae.2010.09.003.

Aspheric soft contact lenses are designed to compensate for spherical aberration of the eye but are they effective? Researchers in Sweden have examined changes in spherical aberration and their effect on visual quality (visual acuity and contrast sensitivity) at both distance and near with non-custom-made aspheric lens designs.

Using the Zywave aberrometer, they measured the aberrations in each of 20 subjects’ eyes uncorrected and with the contact lenses: a standard spherical lens (Dailies Aqua Comfort Plus, CIBA Vision) and two aspheric lenses (SofLens Daily Disposable, Bausch & Lomb; and Zeiss Contact Day 1, Wöhlk). High- and low- contrast visual acuity was measured at distance, and high-contrast visual acuity and contrast sensitivity at near. They found:

• No significant difference between trial frame correction, spherical and aspheric soft lens designs with respect to visual quality, for both distance and near (ie with or without accommodation)
• Mean spherical aberration was positive for all pupil sizes in the uncorrected eye, residual spherical aberration was close to zero with the standard lens for all pupil sizes, but the aspheric lenses over-corrected spherical aberration
• Changes in aberration were statistically significant with all lenses tested

The authors conclude that non-custom-made spherical aberration-control contact lenses have little effect on visual quality. They acknowledge that some subjects, such as those with larger pupils and a larger amount of spherical aberration, could benefit from the lenses and call for further studies of visual quality in this subgroup.

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Characterising dryness symptoms in soft contact lens wearers

Young G, Chalmers RL, Napier L et al. Characterizing contact lens-related dryness symptoms in a cross-section of UK soft lens wearers. Contact Lens Anterior Eye 2010. Published online 10 September 2010. DOI: 10.1016/j.clae.2010.08.005.

Discomfort and dryness are the most common reasons cited for contact lens dropout but little is known about the underlying causes of these symptoms or whether they are more prevalent with some types of lenses than others.

A new study estimates the prevalence of contact lens-related dryness and investigates associated factors in a large population of soft contact lens patients in the UK. It also introduces the Contact Lens Dry Eye Status score to help clinicians determine whether the frequency and intensity of symptoms are significant.

A total of 932 silicone hydrogel (SiH) and hydrogel lens wearers from 12 UK clinical sites completed a self-administered questionnaire on their CL history and wearing experience. A new score based on Contact Lens Dry Eye Questionnaire (CLDEQ) items was used where CL-related dry eye (CL-DE) = frequency of ‘sometimes’, ‘frequently’, or ‘constantly’ plus intensity 3–5; NoCL-DE = frequency of ‘never’ or ‘rarely’ and intensity 0–1; Marginal CL-DE = all other categories. Findings include:

• Prevalence of CL-DE was 31%, Marginal CL-DE 13% and NoCL-DE 56%
• Wearers with CL-DE had significantly lower typical comfort, end-of-day comfort and shorter comfortable wearing times
• Positive CL-DE status was significantly more likely in toric lens wearers (n=129) than spherical lens wearers (43% vs 30%)
• Lens material class, lens care system and gender were not significantly related to CL-DE status
• Use of artificial tears, CLs for dryness, ointments/gels and warm compresses differed between groups according to CL-DE status
• Use of conventional hydrogel lenses was associated with Dry/Marginal status compared with Not Dry both for all subjects and when daily disposable wearers were excluded

The authors conclude that CL-DE score predicts patients’ wearing experience of poorer comfort, shorter comfortable wearing time and increased use of treatments. Although dryness remains an issue for a proportion of soft lens wearers, they observe that it seems to have abated in the last 10 years.

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Under-prescribing of contact lenses for presbyopic correction

Morgan PB, Efron N, Woods CA et al. An international survey of contact lens prescribing for presbyopia. Clin Exp Optom 2010. Published online 6 October 2010. DOI: 10.1111/j.1444-0938.2010.00524.x.

Although new options are emerging for correcting presbyopia with contact lenses, little is known about fitting patterns worldwide. The latest publication from the International Contact Lens Prescribing Survey Consortium reports on data collected in 38 countries over a five-year period from 2005 to 2009.

Survey forms were sent to contact lens fitters in each of the countries between January and March every year. Practitioners recorded data on the first 10 contact lens fittings or refittings performed after receiving the survey. Data were received relating to 16,680 presbyopic (age 45 years or older) and 84,202 pre-presbyopic (15-44 years) contact lens wearers, and showed:

• Significant under-prescribing of contact lenses for presbyopia, although for those who do receive such corrections, three times more multifocal lenses are fitted than monovision lenses
• The largest proportion of fits that are presbyopic are with conventional hydrogel multifocals (16%) followed by silicone hydrogel multifocals (8%)
• Multifocal and monovision prescribing for presbyopes ranges from 79% of all soft lenses in Portugal to zero in Singapore, with the UK in the mid-range
• Presbyopic corrections are most frequently prescribed for full-time wear

The authors say that despite apparent improvements in multifocal design, practitioners are still under-prescribing contact lenses for presbyopia. They argue that training of contact lens practitioners in presbyopic contact lens fitting should be accelerated and research intensified to enhance the prospects of meeting the needs of presbyopic contact lens wearers more fully.

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Pinguecula and contact lenses

Mimura T, Usui T, More M et al. Pinguecula and contact lenses. Eye 2010. Published online 10 September 2010. DOI: 10.1038/eye.2010.120.

Pinguecula is an age-related eye condition frequently seen in clinical practice but its severity in contact lens wear remains unclear. A new study from Japan assesses the relationship between age and the incidence and severity of pinguecula in contact lens wearers, and compares the grade of pinguecula in wearers and non-wearers.

The hospital-based study involved 600 CL wearers aged 11–60 years, of whom 94 wore hard CLs (HCLs) and 506 wore soft CLs (SCLs), and 579 non-wearers aged 10–60 years. Age, gender, medical history, ocular history, and grade of pinguecula at two locations (nasal and temporal) were recorded in all subjects. Grading was on a three-point scale after training using standardised photographs. Results showed:

• An age-related increase in grade of pinguecula among CL wearers and non-wearers
• Prevalence was higher for CL wearers than non-CL wearers at both locations and had a younger onset
• Grade of pinguecula correlated with years of wear in HCL and SCL wearers
• Grade of pinguecula at the temporal conjunctiva was higher in CL wearers than in non-wearers, whereas it was higher in HCL wearers than SCL wearers at both the nasal and temporal conjunctiva

The authors observe that soft contact lenses cause less stimulation of the conjunctiva than rigid lenses and that their larger diameter may also provide limbal protection against UV radiation. Soft lenses can also cover any pinguecula that exists, without causing rubbing.

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Risk factors for CIEs in continuous wear SiH contact lenses

Szczotka-Flynn L, Lass JH, Sethi AK et al. Risk factors for corneal infiltrative events during continuous wear of silicone hydrogel contact lenses Invest Ophthalmol Vis Sci 2010; 51:11 5421-30.

Corneal infiltrative events (CIEs) are known to be associated with overnight contact lens use but their relationship with corneal staining and with microbial contamination on silicone hydrogel (SiH) lenses is unclear. A study by US researchers examines factors associated with increased risk of CIEs from continuous SiH lens wear.

The LASH Study (Longitudinal Analysis of SiH Contact Lens Study) involved a total of 205 subjects fitted with lotrafilcon A lenses (Night & Day, CIBA Vision) for up to 29 nights of continuous wear between October 2006 and February 2008 and followed for 1 year. CIEs were defined and a clinical severity matrix used to calculate a cumulative CIE score per eye for each subject visit. The study found:

• 44 incidents of CIEs in 38 subjects (cumulative incidence 26.7% over 1 year), comprising 11 contact lens acute red eye, 10 contact lens peripheral ulcers, 17 infiltrative keratitis (IK), 5 asymptomatic IK, 1 asymptomatic infiltrate
• 53% of subjects had repeated episodes of corneal staining (mild or greater), and 11.3% had repeated episodes of moderate or greater corneal staining
• Corneal staining was not associated with the development of a CIE
• Frequency of substantial bacterial bioburden on worn lenses at the time of a CIE was 64.7%, compared to only 12.2% during uncomplicated wear
• Substantial lens bacterial bioburden was associated with developing a CIE
• Smoking was also associated with a CIE

The authors conclude that although corneal staining is common in continuous wear with SiH lenses it is not associated with developing a CIE. Smoking and substantial lens bacterial bioburden pose prominent risks. The risk of CIE increases 8-fold in those with substantial lens bioburden and, among this group, 72.3% of the total risk of CIE is attributable to this exposure. Antimicrobial lens surfaces should lower the risk of CIEs, they say.

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Is VA a reliable measure for screening adolescents’ vision?

Leone JF, Mitchell P, Morgan IG et al. Use of visual acuity to screen for significant refractive errors in adolescents. Arch Ophthalmol 2010;128:7 894-899.

Measuring visual acuity (VA) using linear charts is the standard screening method in school age children but can it reliably detect significant refractive error? A new study in a population-based sample of 12-year-olds Australia provides some answers.

The Sydney Myopia Study randomly selected 21 secondary schools stratified by socioeconomic status. All year 7 students (mean age 12.7 years) had monocular VAs measured, unaided at 2.44m, using a logMAR chart. Cycloplegic autorefraction was used to define clinically significant refractive error as a spherical equivalent of –1.00D or more for myopia, at least +2.00D for hyperopia, and –1.00DC or more for astigmatism. Data for both eyes were pooled for a total of 4,497 observations. Results showed:

• VA was generally poor at detecting clinically significant refractive error
• Average VA was 54 letters (6/6–1) and was slightly lower in girls than boys
• Sensitivity and specificity for all clinically significant refractive errors at the best VA cut-off level of 53 letters (6/6–2) were 72.2% and 93.3% respectively
• Myopia had the highest sensitivity and specificity of any of the refractive errors for detection using VA (97.8% and 97.1%) for a 45-letter VA cut-off (6/9.5)
• The best VA cut-offs for hyperopia and astigmatism were 57 (6/6+2) and 55 (6/6) letters respectively, with sensitivities of 69.2% and 77.4%, and specificities of 58.1% and 75.4%

The authors conclude that, in this adolescent group, a VA cut-off of 6/9.5 or less detects almost all cases of myopia (97%). However, there is no reliable VA cut-off for clinically significant hyperopia or astigmatism. Improved screening methods are required to improve detection of these conditions.

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Contact lens solutions can change soft lens modulus

Young G, Garofalo R, Harmer O et al. The effect of soft contact lens care products on lens modulus. Contact Lens Anterior Eye 2010;33:5 210-214.

The ocular effects of different lens/solution combinations have been a focus for soft contact lens research in recent times. But a new study suggests that some solutions may alter an important material property of lenses that affects clinical performance.

Researchers used an Instron 3343 tensiometer to measure the elastic modulus of nine soft lens materials pre-soaked in each of three lens care solutions, ReNu Multi-Purpose (Bausch & Lomb), Opti-Free RepleniSH (Alcon), Clear Care (CIBA Vision) hydrogen peroxide, or a saline control solution. The solutions were changed on Days 1,4 and 6 during the week-long soaking period. Results included:

• All of the lenses, with the exception of senofilcon A (ACUVUE® OASYS™), displayed a significant change in modulus with at least one of the solutions
• The largest changes in modulus were for lotrafilcon B (O2 Optix, CIBA Vision) which showed significant changes with each of the solutions, and lotrafilcon A (Focus Night & Day, CIBA Vision) with Opti-Free RepleniSH
• Notable increases in modulus were found with comfilcon A (Biofinity, CooperVision) and ocufilcon D (Biomedics 55, Coopervision) with peroxide
• Modulus decreased with etafilcon A (ACUVUE® 2) with all three solutions
• Modulus changes were reversible with Opti-Free RepleniSH but not peroxide

The authors conclude that, in the case of the multi-purpose solutions, the changes probably relate to uptake of the formulation components and, in the case of peroxide, to chemical changes to the polymer. Modulus should be compared using lens materials from a similar source using comparable techniques, they say.

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Do children with strabismus suffer from prejudice?

Lukman H, Kiat JE, Ganesan A et al. Strabismus-related prejudice in 5 to 6-year-old children. Br J Ophthalmol 2010;94:1348-1351

Negative perceptions of children with strabismus with respect to physical appearance, personality and capability are well known but there are conflicting reports on whether very young children exhibit strabismus-related prejudice.

A new study in Malaysia explores young children's perception of peers with noticeable exotropia. A total of 128 children aged 5–6 years each viewed four paired images of similar-aged peers with orthotropia and exotropia (one boy and one girl each), and chose the image they liked and the image they would share their favourite toy with. Images were created using digital morphing. Results showed:

• A significantly greater proportion of the sample chose the orthotropic images as the ones they liked (62.7%) and the ones they would share their favourite toy with (60.9%) rather than the exotropic images
• Children tended to give their toys to the faces they preferred

The authors conclude that children as young as five years old have negative social reactions towards peers with noticeable exotropia. To protect strabismic children from possible social alienation and negative psychosocial development, early intervention to correct ocular misalignment may be considered, they say.

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Uptake of research findings in orthoptic treatment of amblyopia

Newsham D. The effect of recent amblyopia research on current practice in the UK. Br J Ophthalmol 2010;94:1352-1357.

Recent studies have provided new insights into how amblyopia may be most effectively managed in areas such as hours of occlusion, use of atropine and compliance measures. A study from the University of Liverpool assesses whether this new evidence has influenced clinical practice in the UK. .

A detailed questionnaire to assess current amblyopia management practice was emailed to the head orthoptist of every eye department in the UK. The 22 questions covered areas investigated in research from 2002-2007. A total of 127 orthoptists took part, a response rate of 68%. Among the findings were:

• Wide variations (0.5 to 12h/day) in the amount of occlusion prescribed for moderate or severe amblyopia. For 60% of clinicians, the maximum they would prescribe was in excess of the 6h recommended by research
• Most departments (67%) did not use treatment protocols for occlusion
• Atropine was rarely recommended as a first-line treatment, with occlusion generally being considered to be more effective
• Despite recommendations for education as a means of reducing non-compliance, only 39% of clinicians always gave written information, although various other methods of enhancing compliance (eg star charts) were used
• Most clinicians (92%) treated patients up to an upper age limit of 8-12 years

One in three respondents said they had made no changes to their prescribing behaviour or treatment protocols in light of recent research. The authors observe that their findings are similar to other areas of medicine, where, on average, it is said to take 17 years for research recommendations to make their way into practice.

CLICK HERE FOR THE ABSTRACT

 

The impact of dry eye on vision-related daily activities

Tong L, Waduthantri S, Wong TY et al. Impact of symptomatic dry eye on vision-related daily activities: The Singapore Malay Eye Study. Eye 2010;24:1486–1491

Dry eye is known to affect the quality of vision but a new study from Singapore has revealed the extent to which this common condition can influence quality of life.

Part of the Singapore Malay Eye Study, the population-based survey involved 3,280 subjects aged 40 years or older (48% men, 52% women) randomly selected from southwestern Singapore. Subjects completed questionnaires on symptoms and vision-related daily activities, and underwent a comprehensive systemic and ocular examination. Symptomatic dry eye was defined as one or more self-reported symptoms that were frequently present (ranked as ‘often’ or ‘all the time’).

In adults without visual impairment, symptomatic dry eye after adjusting for age, gender, and presenting visual acuity was significantly associated with difficulty in seven of the 11 vision-related activities:

• Navigating stairs (odds ratio, OR=1.96)
• Recognising friends (OR=1.99)
• Reading road signs (OR=1.87)
• Reading newspaper (OR=1.50)
• Watching television (OR=1.90)
• Cooking (OR=1.94)
• Driving at night (OR=2.06)

The authors conclude that symptomatic dry eye has a significant impact on quality of life, even in people with good vision. These findings have public health significance and suggest that visual dysfunction in dry eye should be further characterised.

CLICK HERE FOR THE ABSTRACT CLICK HERE FOR A STUDY ON VISUAL COMFORT AND DRYNESS SYMPTOMS IN SOFT CONTACT LENS WEARERS CLICK HERE TO READ MORE ABOUT BLINKING IN CONTACT LENS WEAR

 

Enhancing optical quality and comfort in soft contact lens wear

Koh S, Maeda N, Hamano T et al. Effect of lubricating agents of disposable contact lenses on higher-order aberrations after blinking. Eye & Contact Lens 2008;34:2 100-105.

Can vision as well as comfort be influenced by the incorporation of lubricating agents within soft contact lenses? A study by Japanese researchers of sequential changes in higher-order aberrations (HOAs) of the eye after blinking suggests that it can.

The study involved 15 subjects who wore disposable soft lenses and had dryness-related symptoms, and 15 non-contact lens wearers. HOAs were measured for 60s in each subject after 1h wear of an etafilcon A lens (1•DAY ACUVUE®) or an etafilcon A lens with polyvinyl pyrrolidone (PVP) (1•DAY ACUVUE® Moist). Subjects were forced to blink every 10s similar to the blink rate during computer use. Total HOAs, fluctuation index (FI), and stability index (SI) of total HOAs over time were compared and subjective ocular dryness scored. Results showed:

• In symptomatic wearers, total HOAs and FI were significantly lower with 1•DAY ACUVUE® Moist than with the lens without PVP, and SI was significantly better
• In non-contact lens wearers, only the FI was significantly lower
• In both groups, subjective ocular dryness was significantly lower with1•DAY ACUVUE® Moist than with the lens without PVP

The authors conclude that post-blink changes in aberrations of the eye may reflect symptoms such blurry or fluctuating vision in soft lens wearers. An unstable pre-lens tear film may impair vision quality when the blink rate is reduced. The lens incorporating PVP showed less ocular dryness in both groups of wearers but also resulted in low aberrations and more stable vision in those who were symptomatic.

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Almost one in four children fails to bring spectacles to school

O’Donoghue L, McClelland JF, Logan NS et al. Refractive error and visual impairment in school children in Northern Ireland. Br J Ophthalmol 2010;94:1155-1159.

A study on the prevalence of refractive error and visual impairment in school children in Northern Ireland highlights the need for regular eye tests from an early age and better compliance with vision correction.

The Northern Ireland Childhood Errors of Refraction (NICER) study examined 661 white 12 to13-year-olds and 392 white 6 to 7-year-olds between 2006 and 2008. Tests included logMAR distance acuity, visual acuity (unaided and presenting) and cycloplegic autorefraction. Myopia was defined as –0.50DS or more spherical equivalent refraction (SER) in either eye, hyperopia as +2.00DS SER or more in either eye. Visual impairment was >0.30 logMAR units (6/12). Results showed:

• 17.7% of older children and 2.8% of younger children were myopic, and corresponding levels of hyperopia were 14.7% and 26%
• 7.7% of older children and 7.2% of younger children had presenting visual impairment in either eye, and 19% and 9.9% respectively had uncorrected visual impairment in either eye
• 25% of older children and 12.8% of younger children reported spectacle wear
• Almost one in four children failed to bring their spectacles to school, with similar proportions in each age group (23% and 24% respectively)

The authors say this study is the first to provide robust population-based data on refractive error in white school children in the UK. The high prevalence of monocular presenting visual impairment needs to be addressed and strategies to improve children’s compliance with spectacle wear are urgently needed.

CLICK HERE FOR THE ABSTRACT CLICK HERE FOR A SHORT FILM ON CHILDREN’S EYE CARE

 

A guide to the conjunctiva in soft contact lens wear

Keir N, Woods J and Sickenberger W. The conjunctival response to soft contact lens wear: a practical guide. Optometry in Practice 2010;11:3 123-134.

Many studies have examined the effects of contact lens wear on the cornea but few investigate the impact on the conjunctiva. A review of typical conjunctival responses, viewing techniques, grading considerations, risk factors and management options is therefore welcome.

Among the responses described are:

• Bulbar and limbal conjunctival hyperaemia
• Conjunctival staining
• Conjunctival indentation
• Conjunctival epithelial flaps (CEFs)
• Lid parallel conjunctival folds (LIPCOF)
• Palpebral conjunctival hyperaemia and roughness
• Contact lens papillary conjuncitivis (CLPC)
• Palpebral lid margin conjunctival staining or lid wiper epithelopathy (LWE)

Various management options described include changing lens material, modality, design or fit, increasing replacement frequency, switching lens care solution and prescribing ocular lubricants.

The authors call for more attention to be given to the conjunctiva in order to better understand the significance of these changes and develop appropriate management strategies. They say the ultimate goal is to minimise the physiological impact of soft lens wear and try to eliminate contact lens-related dryness and discomfort.

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Using confocal microscopy to diagnose MK

Garg P. Diagnosis of microbial keratitis. Br J Ophthalmol 2010;94:8 961-962.

Identifying the infecting organism in microbial keratitis (MK) plays a crucial role in management of the disease. An editorial in the British Journal of Ophthalmology reviews the various methods available for diagnosing the aetiology of MK and discusses confocal microscopy as an emerging option.

Currents methods described are:

• Clinical examination: a good history and thorough examination
• Microbiology workup: corneal scraping and culturing
• Corneal biopsy: excising and staining a small piece of corneal tissue

These methods each have their limitations. All provide a static two-dimensional picture of the disease and cannot be used to assess treatment response.

In vivo confocal microscopy (IVCM) using the slit-scanning Nidek Confoscan 4 or laser-scanning Heidelberg Retina Tomograph (HRT) Cornea Module offers several advantages over these conventional diagnostic methods:

• An in vivo technique and a dynamic procedure
• Provides information on the presence of organisms and on their distribution
• Can be used to monitor response to treatment
• Has a very high sensitivity, specificity, positive and negative predictive values

The procedure also has its limitations. Improvement in clinician training and experience, better standardisation of image interpretation, and higher resolution of images is likely to improve the diagnostic accuracy of IVCM further. At this point, the technique may be best used as an adjunctive tool along with clinical characteristics. Its usefulness in assessing treatment response is yet to be explored.

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Contact lenses and MK in deployed military personnel

Musa F, Tailor R, Gao A et al. Contact lens-related microbial keratitis in deployed British military personnel. Br J Ophthalmol 2010;94:988-993.

Military personnel are often deployed in conditions without satisfactory standards of hygiene for contact lens care and where access to treatment may be reduced.

A new study quantifies the effect of contact lens-related microbial keratitis (CLMK) in British Defence personnel, particularly those in active service in the Arabian Gulf and Afghanistan. To define denominator data, 280 soldiers were first questioned on their vision correction preference: 19% needed to use spectacles or contact lenses and, of these, 39% used contact lenses as their primary method of correction. Only 21 (7.5%) said they would be wearing contact lenses while on deployment.

A retrospective review of all British military personnel who developed CLMK during deployment between June 2001 and January 2007 then revealed:

• A total of 27 cases of CLMK (27, eyes, 23 male, median age 26 (range 19–41) years), most of whom (19 cases) were evacuated from Iraq
• 20 cases were associated with soft contact lens wear and one with RGP wear
• Extended wear (EW) monthly lenses were worn in nine cases (33%), daily disposables (DDs) in seven (26%) and EW two-weekly lenses in one case (4%). Those wearing DDs were least likely to lose >1 line of visual acuity (VA)
• Overall incidence of CLMK in contact lens wearers in the British military in Iraq was 35 per 10,000 compared to 4 in 10,000 in the general population
• Incidence increased during the summer months
• 17 eyes (63%) lost >1 line of VA. Nine cases had duty capability downgraded

The authors conclude that although the overall risk of sight loss is low, CLMK is more common and has a poorer outcome in a deployed military environment when compared to a civilian setting. They say deployed personnel who prefer to use contact lenses should avoid overnight wear, maintain strict hygiene and seek medical attention immediately in the event of adverse ocular symptoms.

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Hygienic efficacy of hand-drying techniques

Snelling AM, Saville T, Stevens D et al. Comparative evaluation of the hygienic efficacy of an ultra-rapid hand dryer vs conventional warm air hand dryers. J Applied Microbiology. Published online 7 Sept 2010. DOI: 10.1111/j.1365-2672.2010.04838.x

Hand washing is increasingly recognised as an important infection control measure yet comparatively little research has been carried out to quantify the contribution of hand drying. A new study compares the hygienic efficacy of an ultra-rapid hand dryer (the Dyson Airblade) with two types of warm air dryers.

Fourteen subjects contaminated their hands by handling meat and then washed using a standard technique. After dryer use, transfer of residual bacteria from fingers was quantified. The effect of warm air dryers with and without hand rubbing was then compared with the ultra-rapid dryer and with paper towels. Bacteria transferred from palms, fingers and fingertips before and after drying were counted. Results showed:

• For a drying time of 10s, the ultra-rapid dryer led to significantly less bacterial transfer than the other dryers
• When other dryers were used for 30–35s differences were not significant
• When keeping hands still there was no statistical difference between dryers
• Rubbing when using the warm air dryers inhibited an overall reduction in bacterial numbers on the skin and in many cases numbers increased
• Rubbing with paper towels was best at reducing bacteria

The authors conclude that the ultra-rapid hand dryer is superior to warm air dryers for reducing bacterial transfer with shorter use and may help overcome the problem of users cutting short the drying process. Rubbing hands during warm air drying can counteract the reduction in bacterial numbers accrued during hand washing. But the use of paper towels consistently outperformed all the other drying techniques, especially for bacteria left on the fingertips and palms.

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The science of pterygia

Bradley JC, Yang W, Bradley RH et al. The science of pterygia. Br J Ophthalmol 2010;94:815-820.

Pterygium is a common ocular surface disease attributed to chronic ultraviolet-B exposure. Previous studies have focused primarily on the clinical characteristics and surgical management of pterygia but recent interest in the pathogenesis of the condition provides new insights into this complex disease.

A review article in the British Journal of Ophthalmology examines evidence for possible causative factors. Patients with increased UV-B exposure, such as those living close to the equator, or with sunlight-related conditions such as basal cell carcinoma, have an increased risk of pterygia. UV-B exposure leads to oxidative stress which causes genetic damage and stimulates inflammatory pathways, leading to proliferative tissue growth.

The authors say that a focal alteration of limbal stem cells in pterygia is also key to understanding pterygia pathogenesis. This focal alteration and the predominantly interpalpebral location have been attributed to the focusing of reflected solar radiation on the corneal limbus.

Cell growth-related mechanisms, viral infections and hereditary factors are among possible causative factors but the specific stimulus leading directly to pterygia formation and growth remains a mystery. Further research in this area may allow alternative effective targeted therapeutic strategies for this condition.

CLICK HERE FOR THE ABSTRACT CLICK HERE FOR MORE RESEARCH INTO THE EFFECTS OF UV ON THE EYE

 

Non-compliant behaviours among contact lens wearers

Wu Y, Carnt N and Stapleton F. Contact lens user profile, attitudes and level of compliance to lens care. Contact Lens & Anterior Eye 2010;33:4 183-188.

Poor hand hygiene, inadequate lens care, and not remembering when to come back for aftercare are common non-compliant behaviours in contact lens wearers, according to a new study by researchers in Australia.

A total of 210 wearers attending an optometry clinic and research institute were surveyed on their contact lens hygiene behaviours and attitudes toward lens care. All had worn contact lenses in the previous four weeks and they used all types of lenses. Among 111 of participants responding to the survey (62%), major non-compliance aspects identified were:

• Failing to wash hands prior to lens handling (11%)
• No rinsing of lenses (37%)
• Topping up and failing to always use disinfecting solution (13%)
• Prolonged use of lens storage cases, >6 months (22%)
• Wearing lenses for water sports without using swimming goggles or daily disposables (59%)

Half of respondents (51%) failed to remember or said that no advice was given on how often they were to return for aftercare. Those who bought lenses via the internet were 3.8 times more likely to forget their aftercare schedule than those who purchased them from optometrists.

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Effects of age and gender on the tear film

Guillon M and Maissa C. Tear film evaporation. Effect of age and gender. Contact Lens & Anterior Eye 2010;33:4 171-175.

Guillon M and Maissa C. Tear film dynamics and lipid layer characteristics. Effect of age and gender. Contact Lens & Anterior Eye 2010;33:4 176-182.

Dry eye disease is known to be more prevalent in older subjects and in women rather than men. Two new papers by UK-based researchers investigate the influence of tear film evaporation and tear dynamics on dry eye problems by age and gender.

The first study involved 160 subjects <45 years old and 57 subjects aged ≥45 years. Tear film evaporation was measured with the Oregon Health Sciences University Evaporimeter at 30% and 40% humidity. The second study reported results for the same 160 subjects <45 years and 58 subjects aged ≥45 years. Tear film dynamics (non-invasive break up time) and lipid characteristics (lipid layer thickness and contamination) were assessed using the Tearscope device.The results revealed:

• Tear evaporation rate was higher in the older age group at both humidities and overall was higher for women
• Tear evaporation rate in older women was 34-80% higher than that of older men and 36-69% higher than younger women
• Tear film stability was mostly influenced by age and break up time was shorter for the older age group
• The lipid layer was thinner for subjects aged ≥45 years with a marked synergistic effect of age and gender
• The lipid layer of older women was thinner and more contaminated than that of younger women and of older men

The authors conclude that ageing of the tear film, particularly in women, has an evaporative component, and that destabilisation associated with changes in the tear lipid layer produces less protection from evaporation. Strategies that protect the eye from adverse environments and treatment for blepharitis and meibomian gland dysfunction should be added to conventional management with aqueous eye drops.

CLICK HERE FOR THE ABSTRACT OF THE FIRST PAPER CLICK HERE FOR THE ABSTRACT OF THE SECOND PAPER

 

Improving communication and compliance through training

Hahn SR, Friedman DS, Quigley HA et al. Effect of patient-centered communication training on discussion and detection of non-adherence in glaucoma. Ophthalmology 2010;117:1339-1347.

Communication and compliance are buzzwords in all healthcare practice but what can eye care practitioners learn from experiences in the medical profession and can communication skills be learnt?

A US study assessed doctor-patient communication in glaucoma care and evaluated the impact of training in patient-centred communication techniques in detecting and managing non-compliance.

Baseline doctor-patient communication was studied using audio and videotaped encounters and post-visit interviews and questionnaires. Physicians then received 3 hours of training in compliance in chronic disease and glaucoma, and in patient-centred communication. Two weeks after training, the same physicians were observed with different patients. In all, 23 experienced physicians and 100 patients with glaucoma took part. Results showed:

• With training, physicians increased the proportion of open-ended questions (15% vs 6%) and questions specifically about medication-taking (82% vs 18% of encounters)
• Ask-tell-ask communication was absent at baseline but 32% of encounters after training included a complete ask-tell-ask sequence, 78% included an ask-tell sequence, and 32% a tell-ask sequence
• 3 out of 4 steps for assessing non-compliance were more common after training and non-compliance was discussed (86% vs 30% of encounters)
• After training, physicians elicited acknowledgment of non-compliance in 78% of patients (who admitted non-compliance in the post-visit interview) compared with 25% before training

This study demonstrates that experienced community physicians improved their communication strategies and ability to detect and address non-compliance after a 3-hour educational programme.

CLICK HERE FOR THE ABSTRACT

 

Quality of life benefits for young contact lens wearers

Rah MJ, Walline JJ, Jones-Jordan et al. Vision specific quality of life of pediatric contact lens wearers. Optom Vis Sci 2010; Published online 17 June 2010 doi: 10.1097/OPX.0b013e3181e6a1c8.

Several studies have shown that children are capable of wearing and caring for contact lenses, but some of the benefits of contact lens wear are less tangible. The latest research from the ACHIEVE Study Group compares the vision-related quality of life benefits of spectacles and contact lenses.

A total of 484 myopic children aged 8-11 years who wore spectacles at baseline were randomly assigned to wear contact lenses (n=247) or spectacles (n=237) for 3 years. Most (93%) were fitted with 1•DAY ACUVUE® lenses and the remainder with ACUVUE® 2 two-weekly replacement lenses.

The Pediatric Refractive Error Profile (PREP) survey was administered at the baseline examination, at 1 month, and every 6 months for 3 years. The survey included 11 scales: activities, appearance, distance and near vision, handling, peer perception, satisfaction, academics, symptoms, overall vision and overall PRPP.

• Over 3 years, overall quality of life improved 14.2 units for contact lens wearers and 2.1 units for spectacle wearers
• In all scales except visual performance scales (distance, near and overall vision), quality of life improved more for older subjects than younger subjects (11 years old vs 9 years old)
• A surprising finding was improved quality of life reported with regard to handling contact lenses compared to spectacles
• Scales with the largest improvement in quality of life for contact lens wearers were activities, appearance, and satisfaction with correction.

Older children, children who participate in recreational activities such as sports or dance, children who are motivated to wear contact lenses, and children who do not like their appearance in spectacles will benefit most from contact lens wear.

CLICK HERE FOR THE ABSTRACT CLICK HERE TO READ MORE ABOUT THE BENEFITS OF CONTACT LENSES FOR CHILDREN AND TEENS

 

Protection factors for UV-blocking contact lenses

DeLoss KS, Walsh EW and Bergmanson JPG. Current silicone hydrogel UVR blocking lenses and their associated protection factors Contact Lens & Anterior Eye 2010;33: 136-140.

Sun protection factors (SPFs) are well established for skin care products but contact lenses have no simple classification for their level of ultraviolet (UV) protection.

A new study measured the UV blocking properties of silicone hydrogel (SiH) lenses approved by the US Food and Drug Administration and then used spectral transmittance data to calculate their ocular protection factor (PF).

Lenses tested were ACUVUE® Advance®, ACUVUE® Oasys® and Avaira. A UV-blocking hydrogel, Precision UV, and non-blocking SiH, O2Optix, were used for comparison. Field measurements were taken in ambient sunlight using a radiometer. Spectral transmittance at the centre and periphery of the lenses was then plotted by spectrophotometry and PF values calculated for each lens type. The study found:

• A range of 50%cut-off wavelengths across the lenses, from 370 nm for Avaira to 390 nm for Precision UV, with O2Optix transmitting down to 265 nm
• ACUVUE Advance and ACUVUE Oasys were the strongest UVB blockers
• A 2-3 nm difference from centre to periphery across a -3.00D contact lens for all UV blockers
• UV reduction calculated from transmittance data correlated well with field data, ranging from 90-98% for UV blockers to 13% for the non-blocker
• PF value at centre was highest for ACUVUE Oasys (5.7, and 6.3 at periphery)

The authors call for the development of the ocular protection factor concept which quantifies the actual reduction of UVR, to simplify the classification of contact lenses. This would assist public and practitioners, and facilitate awareness of the risks of UV radiation to the eye. They say UV blocking lenses and their PF should be an important element to consider when prescribing lenses to protect the entire cornea and limbus.

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Wearing times for children’s vision correction

Jones-Jordan LA, Chitkara M, Coffey B et al. A comparison of spectacle and contact lens wearing times in the ACHIEVE study. Clin Exp Optom 2010;93:3 157-163.

Fitting contact lenses to children and teens is a major focus for current contact lens research, with several large-scale ongoing studies.

The latest findings from the ACHIEVE (Adolescent and Child Health Initiative to Encourage Vision Empowerment) study compare wearing times with soft contact lenses (1•DAY ACUVUE® or ACUVUE® 2) and with spectacles, in myopic children and teenagers. A total of 484 subjects aged 8-11 years were enrolled in the study.

Parents provided wearing times for spectacle and contact lens wear. Hours wearing primary correction and total correction were compared between the two groups.

• Average wearing time was 91.5 h per week for the spectacles group compared to 80.3 h per week for the contact lens wearers
• Total correction time was slightly higher for the contact lens wearers than for the spectacles wearers, at 97.5 h and 91.5 h respectively
• Higher refractive error was strongly related to longer wearing times
• Young contact lens wearers (<10 years) wore their lenses less than young spectacle wearers and older contact lens wearers, but still wore them, on average, 74.4 h per week.
• Gender, spectacle satisfaction and activities were not related to wearing time

While contact lens wearing children and teens use their lenses less than spectacle wearers, they spend roughly the same amount of time in vision correction. Contact lenses are a viable alternative mode of correction for children, the authors say.

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Contact angle is a poor predictor of biocompatibility

Menzies KL and Jones L. The impact of contact angle on the biocompatibility of biomaterials. Optom Vis Sci 2010;87:6 387-399.

A key parameter for all biomaterials is surface wettability but does enhancing wettability result in improved biocompatibility?

Researchers in Canada examine this question by reviewing the impact of contact angle on the biocompatibility of tissue engineering substrates, blood-contacting devices, dental implants and intraocular lenses, as well as contact lens materials. They also look at the role of contact angle in biofilm formation.

Their review includes a description of the three main techniques for measuring in vitro wettability: sessile drop, captive bubble and the Wilhelmy balance method, and the pros and cons of each. They use two of these methods to compare the contact angles of a range of silicone hydrogel (SiH) materials. The paper also compares other material properties and surface treatments for current SiH lenses.

The authors conclude that, to date, laboratory-based contact angle measurements do not predict in-eye performance. Contact angle is poorly predictive of bacterial biofilm development and other properties, such as surface roughness, appear to be more relevant. More sophisticated methods are needed to investigate biomaterial surface properties and help predict their long-term performance.

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Simple measures prevent the spread of infection

Jefferson T, Del Mar C, Dooley L et al. Physical interventions to interrupt or reduce the spread of respiratory viruses: systematic review. BMJ 2009;339:b3675. doi: 10.1136/bmj.b3675.

New viral infections such as the h2N1 flu pandemic have focused attention on infection control. A review in the British Medical Journal looks at evidence of the effectiveness of public health measures in reducing the spread of respiratory viruses.

The review included 59 studies, eight of which were incorporated in this 2009 update of a Cochrane review in 2007. Meta-analysis of six case-control studies suggested that the following physical measures are highly effective in preventing the spread of severe acute respiratory syndrome:

• Handwashing more than 10 times daily (odds ratio 0.45)
• Wearing gloves (OR 0.43)
• Wearing masks (OR 0.32)
• Wearing gowns (OR 0.23)

The incremental effect of adding virucidals or antiseptics to normal handwashing to reduce respiratory disease remained uncertain. Evidence was also limited for social distancing (such as isolation or quarantine) being effective. Most effect can be expected from hygiene measures in younger children and household members.

The authors recommend that handwashing programmes be implemented nationwide. In situations of high risk of transmission, barrier measures should be implemented such as wearing gloves. Greatest effort should be concentrated on young children through regular education at school on hygiene.

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Choice of vision correction as a falls prevention strategy

Haran MJ, Cameron ID, Ivers RQ et al. Effect on falls of providing single lens distance vision glasses to multifocal glasses wearers: VISIBLE randomised controlled trial. BMJ 2010;340:c2265. doi: 10.1136/bmj.c2265.

Several recent studies have examined the role of vision correction in the mobility of elderly people. The latest looks at whether providing older wearers of multifocal spectacles with single-vision (SV) distance spectacles can reduce falls.

Researchers in Australia recruited 606 multifocal (bifocal, trifocal, or progressive) spectacle wearers with a mean age of 80 years. Inclusion criteria included increased risk of falls (fall in previous year or timed ‘up and go’ test >15 seconds) and outdoor use of multifocals at least three times a week. SV distance spectacles were given to 275 (90%) of the 305 test group to use for walking and outdoor activities (but not for seated tasks), and 301 controls received their usual care.

• 162 (54%) of the test group reported satisfactory use of distance spectacles for walking and outdoor activities for at least 7 out of 12 months after dispensing
• In the 299 test and 298 control participants who completed monthly follow-ups, intervention reduced falls by 8%.
• Intervention was effective in significantly reducing all falls, outside falls, and injurious falls in people who regularly took part in outside activities
• A significant increase in outside falls occurred in people in the test group who took part in little outside activity.

The authors say that, with appropriate counselling, providing single-vision spectacles is an effective falls prevention strategy for older wearers of multifocal spectacles who take part in regular outdoor activities. Those with low distance errors should remove their multifocals when walking outdoors. Multifocal wearers with low levels of outdoor activity should use them for most activities.

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A ‘cost-per-wear’ model for contact lens replacement

Efron N, Efron SE, Morgan PB et al. A ‘cost-per-wear’ model based on contact lens replacement frequency. Clin Exp Opton 2010;93: 253-260.

Cost is just one factor in the choice of contact lens type but an important consideration that is often neglected in the literature. A model developed in Australia introduces the concept of ‘cost-per-wear’ to allow direct comparison of the cost of different lens replacement frequencies.
Cost-per-wear is the total cost incurred by a patient over 12 months, taking into account professional fees and cost of lenses and solutions, and dividing this by the number of times the lenses are worn over that period. Assumptions include a consultation fee of A$151 (c £84) per year. The model is presented graphically as the cost-per-wear versus the number of times lenses are worn each week.

Cost-per-wear for spherical lenses:

• for 2-weekly and monthly replacement is almost identical but decreases with increasing frequency of wear
• for daily replacement is lower than for reusable lenses when worn 1-4 days per week but higher when worn 6-7 days per week
• is virtually the same for all three lens replacement frequencies (A$3.00 or c£1.67) at 5 days’ wear per week
• A similar but higher cost pattern is observed for toric lenses, with cross-over at 3-4 days’ wear per week (A$4.80 or c£2.67)
• Multifocal lenses have cross-over points for daily versus 2-weekly lenses at 4-5 days’ wear per week (A$5.00 or c£2.78) and for daily versus monthly lenses at 3 days per week (A$5.50 or c£3.06).

The authors say the model can be applied to the cost of contact lens wear in different countries and that relative costs of different forms of lens wear are unlikely to vary. Practitioners could also use the principle to examine the impact of different cost inputs and assumptions in their own practices.

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Key questions on contact lenses and MK

Fleiszig SMJ and Evans DJ. Pathogenesis of contact lens-associated microbial keratitis. Optom Vis Sci 2010;87:4 225-232.

Good hygiene minimises microbial contamination in contact lens wear but improving compliance alone is ineffective in preventing infection, according to a review paper on the pathogenesis of contact lens-associated microbial keratitis (MK) by researchers at the University of California-Berkeley.

The authors review published literature to answer key questions such as:

• Would it help if contact lens wearers were more compliant?
• Why is extended wear a risk factor?
• Are antimicrobial lenses a good idea?
• Does fluorescein staining predict risk of infection?
• Is hypoxia a risk factor?
• What is the relationship between infection and inflammation?
• Why not just advocate daily disposable lenses?

Discovering how and why contact lens wear impacts the ocular surface will advance our understanding of corneal health and disease, the authors conclude.

CLICK HERE FOR THE ABSTRACT

 

Understanding bioburden on lenses, solutions and cases

Szczotka-Flynn LB, Pearlman E and Ghannoum M. Microbial contamination of contact lenses, lens care solutions, and their accessories: a literature review. Eye Contact Lens 2010;36:2 116-29.

Thirty years of research into the incidence, number and type of microorganisms that adhere to contact lenses and are present in solutions and lens cases is summarised in a new review by researchers at the Case Western Reserve University, Ohio.

The review hypothesises the role that microorganisms play in contact lens infection and inflammation. It also explores patient compliance and case hygiene, mechanisms to prevent bacterial colonisation of lenses and cases, and the impact these might have on the incidence of contact lens complications. Findings include:

• Lens handling greatly increases the incidence of lens contamination
• Even when removed aseptically from the eye, more than half of lenses harbour microorganisms (almost exclusively bacteria) but the ocular surface tolerates their presence under normal conditions
• The incidence of microbial bioburden in cases is typically greater than 50%
• All solutions can become contaminated, including up to 30% of preserved products

The authors conclude that a detailed understanding of lens-related bioburden is important in understanding factors associated with infectious and inflammatory complications. Mechanisms to prevent colonisation, such as anti-bacterial lenses and cases, show promise and may decrease the incidence of complications.

CLICK HERE FOR THE ABSTRACT

 

What can we learn from 20 years of MK research?

Keay L. Epidemiology of contact lens-related microbial keratitis. Optometry in Practice 2010;11:2 43-50.

This review paper looks at 20 years of epidemiological studies evaluating the rates and risk factors for MK, the rare but most severe complication of contact lens wear. Key findings are summarised as follows:

• Four contact lens wearer in 10,000 per year experience an episode of MK
• The annual risk of losing vision from contact lens wear is 0.3-0.9 per 10,000 which compares favourably with other options such as laser refractive surgery
• The risk is about 5X higher in overnight wear compared to daily wear
• In extended wear, MK rates with silicone hydrogels and hydrogels are similar
• Poor hygiene, particularly not replacing cases, increases the risk of MK
• More than 3 out of 4 cases of MK (77%) could be prevented if lenses were not worn overnight and if hygiene were maintained

The author concludes that continuing to educate contact lens wearers about the right way to look after their lenses is an important step in safe contact lens use. Education about what to do if an infection occurs may also increase the likelihood of a favourable outcome.

CLICK HERE FOR THE ABSTRACT

 

A systematic approach to managing red eye

Thampy RS and Kwartz J. Clinical decision-making for optometrists in management of the red eye. Optometry in Practice 2010;11:2 51-56.

The red eye is one of the most commonly encountered signs presenting in eye care practice and one of most important for optometrists to diagnose and manage.

This paper by ophthalmologists at the Royal Bolton Hospital is aimed at developing effective strategies for decision-making in red eye, as well as reviewing the many causal conditions and their management. Among useful tips are:

• Avoid obscurity! Recognise that common conditions are common and be aware of what occurs in your area
• Learn to recognise patterns and use a systematic approach
• When managing diagnostic uncertainty, a careful history is all-important
• Involve the patient and gain consent for your referral decisions
• Request feedback from GPs and hospitals to reflect and build on your referral practices

The authors say that by adopting these principles, practitioners can pursue a methodical and robust approach to a variety of red-eye problems.

CLICK HERE FOR THE ABSTRACT

 

School’s out! Outdoor activities and myopic progression

Deng L, Gwiazda J and Thorn F. Children’s refractions and visual activities in the school year. Optom Vis Sci 2010;87:6 406-413.

Research has shown that non-myopes have more hours of outdoor activity during the school year which may protect against myopia development. A new US study investigates the link between children's refractive errors and visual activities in the summer break (June, July, and August) as well as during the school year.

Parents of 147 children aged 6-18 years reported the number of weekly hours outside school and during the summer break that the children read for pleasure, studied, watched TV, used the computer/played video games, and engaged in sports/outdoor activities. Among the findings were:

• During the school year, myopes spent significantly fewer hours than non-myopes on sports/outdoor activity (8.25 vs 10.95 h/week) and watched more television than non-myopes (12.78 vs 8.91 h/week)
• No significant refractive group differences were found for other activities
• During the summer break, no significant differences were found between refractive groups in any visual activity times
• The biggest differences between summer and school activity times were in outdoor activity (21.76 vs10.34 h/week) and studying (1.69 vs 9.51h/week).

As in previous studies, non-myopes had a higher number of weekly sports/outdoor activity hours during the school year, which may protect against myopia development. A new finding is the high number of sports/outdoor activity hours for both myopes and non-myopes during the summer break, which the authors suggest may contribute to slowed eye growth in all children during these 3 months.

CLICK HERE FOR THE ABSTRACT

 

In the dark about impaired vision and night driving

Wood J, Chaparro A, Carberry T el al. The effect of simulated visual impairment on nighttime driving performance. Optom Vis Sci 2010;87:6 379-386.

The importance of good eyesight when driving may seem obvious but evidence for the effects of impaired vision on drivers’ performance is surprisingly hard to find. A new study in Australia simulated visual impairment then tested nighttime driving performance under real-road conditions on a closed road circuit.

Twenty young subjects with normal vision were tested under three visual conditions: normal vision, simulated cataracts and refractive blur, incorporated in goggles. Visual acuity (VA) levels for cataract and blur conditions were matched for each subject.

Driving measures were sign recognition, avoidance of low contrast road hazards, time to complete the course, lane keeping and pedestrian recognition.

• Simulated visual impairment significantly reduced participants' ability to recognise road signs, avoid road hazards, and increased the time taken to complete the driving course
• The effect was greatest for cataract simulation, where contrast sensitivity (CS) was reduced even though cataract and blur conditions were matched for VA
• Although visual impairment also significantly reduced the ability to recognise a pedestrian wearing black clothing, a pedestrian wearing special clothing with reflective markings on the limb joints was seen 80% of the time

Driving performance under nighttime conditions was significantly degraded by modest visual impairment and these effects were greatest for the cataract simulation. Pedestrian recognition was enhanced by clothing marking limb joints in the pattern of ‘biomotion’, which was relatively robust to the effects of visual impairment. This clothing should be adopted by pedestrians with high levels of exposure at nighttime, such as road workers and emergency service personnel.

CLICK HERE FOR THE ABSTRACT

 

A suitable case for investigation

Wu YT, Zhu H, Willcox M et al. Impact of air-drying lens cases in various locations and positions. Optom Vis Sci. Published online May 6 2010. doi: 10.1097/OPX.obo13e3181e172a1.

Should contact lens storage cases be dried face-up or face-down? A recent study looked at the rate and type of microbial contamination when cases were air-dried in face-up and face-down positions and in four different locations.

A total of 97 unused cases were rinsed with sterile phosphate buffered saline then placed on paper tissues in different locations: humid (toilet and bathroom) and non-humid (office and bedroom), to air-dry at room temperature. After 24h, the cases were collected and sampled. The microbial profile and rate of contamination between different locations and positions were compared.

• Irrespective of location, cases positioned face-up had a significantly higher contamination rate (71%) compared with cases air-dried face-down (12%)
• For cases air-dried face-up, there was more contamination in humid (toilet and bathroom) than in non-humid (office and bedroom) environments
• Contamination rates did not differ between locations when air-dried face-down
• Total microorganisms recovered ranged from 0-275 colony forming units per well. Most frequent were Staphylococci, fungi, and Bacillus species and a third (33%) were contaminated with multiple species.

The authors conclude that small numbers of microorganisms from the environment may contaminate contact lens cases when air-dried face-up. Cases air-dried in humid environments have higher levels of contamination and this is particularly true when cases are positioned face-up. Cases should therefore be air-dried face-down.

CLICK HERE FOR THE ABSTRACT CLICK HERE FOR THE VISION CARE INSTITUTE’S INSIGHTS AND BEST PRACTICE ON CASE CARE

 

Omega-3 and -6 fatty acids may benefit dry eye patients

Roncone M, Bartlett H and Eperjesi F. Essential fatty acids for dry eye: A review. Contact Lens Anterior Eye 2010;33:49-54.

Studies into the relationship between dry eye and nutrition have prompted interest in the use of dietary supplements or modifying diet as a potential treatment.

A review paper by researchers at Aston University investigates whether essential fatty acids (EFA), particularly omega-3 EFA, may be effective in dealing with the underlying causes of dry eye syndrome. A literature review of the PubMed, ScienceDirect and Ovid databases identified all relevant articles published between 1950 and 2008. Among the findings were:

• Omega-3 EFA (found in selected fish, fish oils, seafood, flaxseed, nuts and beans and green leafy vegetables) and omega-6 EFA (in vegetable oils, poultry, eggs, cereals and wholegrain breads) need to be consumed together and within a given ratio (ideally 1:2) to be effective
• Typical diets in developed countries lack omega-3 EFA and this results in an overexposure to omega-6
• Omega-3 supplementation has an anti-inflammatory effect, inhibiting creation of omega-6 prostaglandin precursors
• Omega-3 EFAs also demonstrate anti-inflammatory action in the lacrimal gland. Supplementation clears meibomitis, allowing a thinner, more elastic lipid layer to protect the tear film and cornea

The authors conclude that supplementation with omega-3 EFA may be beneficial in treating and preventing dry eye syndrome. Eye care professionals should familiarise themselves with EFAs, their benefits and also their potential side-effects, they say.

CLICK HERE FOR THE ABSTRACT

 

Liposomal spray for dry eye: does it work?

Craig JP, Purslow C, Murphy PJ et al. Effect of a liposomal spray on the pre-ocular tear film. Contact Lens Anterior Eye 2010;33 83-87.

A novel spray which delivers phospholipid liposomes to the tear film via the surface of the closed eyelid is designed to address evaporative dry eye. But does it work?

A new study led by Dr Jennifer Craig evaluated the short-term effects of liposomal spray application on the pre-ocular tear film in 22 non-contact lens wearing subjects (12M, 10F, aged 35±7) with normal eyes. The spray (Tears Again, marketed in the UK as Optrex ActiMist) was applied to one eye, and an equal volume of saline spray to the contralateral eye. Lipid layer grade (LLG), non-invasive tear film stability (NIBUT), tear meniscus height (TMH) and subjective comfort were evaluated at baseline, and at 30, 60, 90 and 135 min post-application.

• LLG increased significantly, at 30 and 60 min, only in treated eyes
• NIBUT also increased significantly in treated eyes only, at 30, 60 and 90 min, but TMH did not alter significantly
• Comfort improved relative to baseline in 46% of treated and 18% of control eyes, at 30 min post-application. Of those expressing a preference in comfort between the eyes, 68% preferred the liposomal spray

Consistent with subjective reports of improved comfort, statistically and clinically significant improvements in lipid layer thickness and tear film stability are observed in normal eyes for ≥1 h after a single application of liposomal spray. A similar study is now underway in patients with evaporative dry eye.

CLICK HERE FOR THE ABSTRACT

This is one of several articles on dry eye in a special issue of Contact Lens & Anterior Eye, which also includes comments on the role of eye care professionals in dry eye management by guest editors Dr Robin Chalmers and Dr Michel Guillon.

CLICK HERE FOR THE TABLE OF CONTENTS

 

Are parents a barrier to teenagers wearing contact lenses?

Zeri F, Durban JJ, Hidalgo F et al. Attitudes towards contact lenses: A comparative study of teenagers and their parents. Contact Lens Anterior Eye (2010), doi:10.10.1016/j.clae.2009.12.009.

How do parents influence their children’s attitudes to contact lenses? This is the intriguing question posed by the authors of a new study from the Contact Lens Evolution Study Group based at the University of Rome.

The group surveyed adolescents (aged 12-18 years) and their parents attending clinics in Italy (phase 1) and Iberia (Spain and Portugal; phase 2). In phase 1, around one-third of adolescents (34% of 146) and parents (36% of 114) were contact lens wearers. In phase 2, none of the 223 adolescents but 27% of the 230 parents wore contact lenses.

The extent to which contact lenses satisfy aesthetic, visual, and practical needs and their effectiveness, safety, and comfort in the general population and in adolescents was rated by respondents on a 5-point Likert scale. Results showed:

• Most adolescents (77.5%) and parents (66.2%) expressed a high interest in CL use in phase 2 despite none of the adolescents currently wearing CLs
• Across both phases, adolescents and parents agreed that CLs met an aesthetic need in adolescents.
• Parents, but not adolescents, perceived that CLs were significantly less safe in adolescents than in the general population
• Among 50% of parents (mainly mothers),significant concerns about CLs were: difficulties following instructions and taking care of the CLs and potential eye damage, which, in mothers, led them to show less agreement towards CL use

The authors highlight an essential need for improved communication and education on contact lens use for parents and teens, as well as in the general population.

CLICK HERE FOR THE ABSTRACT

 

Factors influencing the decision to opt for LASIK

Lazon de la Jara P, Erickson D, Erickson P et al. Pre-operative quality of life and psychological factors that influence patient decision-making in LASIK. Eye 2010;24:270-275.

What motivates myopes to choose LASIK and how do these patients differ from successful contact lens wearers? A recent study used a specially developed assessment tool, the Institute for Eye Research Quality of Life (IER QOL) Scale, to find out.

Researchers assessed visual function, psychological factors, personality traits and satisfaction in 183 low to moderate myopes (wearing spectacles or contact lenses) seeking LASIK at a refractive surgery centre in Peru. Results were compared with 23 successful contact lens wearers not interested in LASIK. Among the findings were:

• Of 183 patients seeking LASIK, 30 declined the procedure
• Of 153 who went ahead, 51 patients failed to present for their 3-month post-operative follow-up appointment.
• Successful soft contact lens wearers reported significantly better functional vision, felt more attractive, had a lower frequency of disturbing visual and ocular symptoms, and higher overall satisfaction with their current optical correction than those seeking LASIK

The authors conclude that psychological characteristics, perception of visual and ocular symptoms and satisfaction with current method of correction play an important role in the decision to undergo LASIK. Self perception of attractiveness may be an important driver for those seeking LASIK. Those who do go ahead are likely to be risk takers and those who adapt easily to new situations.

CLICK HERE FOR THE ABSTRACT

 

New advice on contact lens case hygiene and design

Wu YT, Carnt NB, Willcox M et al. Contact lens and lens storage case cleaning instructions: whose advice should we follow? Eye & Contact Lens 2010;36:2 68-72.

Wu YT, Zhu H, Harmis N et al. Profile and frequency of microbial contamination of contact lens cases. Optom Vis Sci 2010;87:3 E152-E158.

The importance of the contact lens storage case to successful and safe contact lens wear is highlighted in two papers from Australian researchers.

In the first study, a team at the Institute for Eye Research compared instructions from three sources: product inserts of five multipurpose solutions; the US Food and Drug Administration (FDA) website; and a survey of 77 optometrists on their recommended hygiene measures. Among the findings were:

• Case cleaning instructions were inconsistent, and limited advice was given about drying position, rinsing, and rubbing of cases
• For example, the FDA recommends air drying cases face down but 42% of optometrists recommend air drying cases face up
• Lens cleaning instructions were more comprehensive and included lens cleaning time and rubbing
• Confusion remained over some of the cleaning instructions, for rubbing and rinsing lenses in particular

The authors call for future research to establish evidence-based storage case hygiene guidelines, and better communication not only between eye care professionals and lens wearers but also within the eye care industry.

The second study examined the profile and frequency of microbial contamination of 64 contact lens cases used by asymptomatic wearers, and whether different areas of the same lens case – the upper rim and the lower base – were affected. Two types of case were investigated: flat well and stand-up basket. Results showed:

• Overall 58% of cases were contaminated (55% of two-well polypropylene cases, 63% of silver-impregnated cases and 67% of stand-up cases)
• For flat-well cases, more microorganisms were recovered from the upper rim than from the lower base
• For stand-up cases, more microorganisms were recovered from the lens basket than the upper hinge
• For both types, the base of the case well had a higher recovery rate of Micrococcus spp and coagulase-negative Staphylococci than the upper rim
• Lens cases <9 months old had lower levels of contamination than older cases

These authors point to a ‘carry-over effect’ from worn contact lenses to the case. Allowing the lens or finger to come into contact with the upper inner rim when removing the lens from the case may be a threat to safe wear. They recommend frequent replacement of lens cases (at least every 3-6 months) and better designs to reduce microbial contamination in the areas at risk.

CLICK HERE FOR THE ABSTRACT ON CASE CLEANING CLICK HERE FOR THE FULL TEXT ON CASE CONTAMINATION AND DESIGN

 

Large-scale study determines rate of infection following LASIK

Llovet F, de Rojas V, Interlandi E et al. Infectious keratitis in 204,586 LASIK procedures. Ophthalmol 2010;117:232-238.

Microbial keratitis is an increasingly recognised complication of refractive surgery but the occurrence rate is difficult to estimate and varies widely. A new retrospective study of post-LASIK keratitis is the largest case series to date with all procedures carried out at the same institution.

This was a retrospective study of 204,586 LASIK procedures (in 107,613 patients) carried out in Spain between 2002 and 2008. Those with a diagnosis of infectious keratitis within 6 months of primary LASIK or enhancement surgery were identified from medical records and postoperative outcomes analysed. Results showed:

• Post-LASIK infectious keratitis was diagnosed in 72 eyes from 63 patients, an incidence of 0.035% per procedure (or one case in 2,841 procedures).
• Onset of infection was early (within 7 days after surgery) in 62.5% of cases
• Final best spectacle-corrected visual acuity (BSCVA) was better than or equal to 6/6 in 38 cases (52.7%) and better than or equal to 6/12 in 67 cases (93.05%)
• Final BSCVA was worse than 6/12 in 5 cases (6.94%).

The authors conclude that infectious keratitis after LASIK is a potentially sight-threatening complication. The infection rate found in this study is lower than or similar to that found in other studies. Prompt and aggressive management with early flap lifting, scraping, culture, and irrigation with antibiotics is strongly recommended, and can result in preserving useful vision.

CLICK HERE FOR THE ABSTRACT

 

New guidance on decontaminating trial contact lenses

Buckley RJ. Decontamination. Optometry in Practice 2010;11:27-32.

New advice on the reuse and decontamination of trial contact lenses and ophthalmic devices that come into contact with the eye has highlighted the importance of effective cleaning.

Previous guidance was issued in 2001 amid fears that Creutzfeldt-Jacob disease and its variant form (vCJD), the human form of bovine spongiform encephalopathy (BSE, ‘mad cow disease’), could potentially be transmitted by such devices.

A review article by Professor Roger Buckley describes the new decontamination procedures in light of current knowledge of the low potential for infectivity of the anterior eye, and the cornea and conjunctiva in particular. Among the findings are:

• Since 1995, 170 people in the UK have contracted vCJD
• Ocular tissues, other than the retina and optic nerve, are either designated in the low infectivity category (cornea) or as having no detected infectivity (tears)
• Only one case of CJD has been positively attributed to a corneal transplant among hundreds of thousands of recipients and this was a ‘possible’ case of transmission by this route, which might be regarded as unproven
• Revised guidance on decontamination emphasises thorough cleaning to remove cellular debris and adherent protein

The author concludes that disposability of lenses and devices is preferable to reuse, but where this is not possible or not in the best interest of patients, the new guidance will result in the safest practicable outcome.

CLICK HERE TO ACCESS THE PAPER IN OPTOMETRY IN PRACTICE CLICK HERE FOR THE FULL GUIDANCE FROM THE DEPARTMENT OF HEALTH CLICK HERE FOR THE COLLEGE OF OPTOMETRISTS’ AND ABDO GUIDANCE CLICK HERE FOR A SUMMARY OF OUR RECOMMENDED PROCEDURE

 

A review of the latest thinking on safe contact lens wear

Keay L, Edwards K and Stapleton F. An evidence-based brochure to educate contact lens wearers about safe contact lens wear. Clin Exp Optom 2009;92:5 407-9.

Recent studies in Australia, New Zealand and the UK have added to our understanding of contact lens-associated microbial keratitis (MK) and the risk factors involved. In Clinical and Experimental Optometry, Keay and colleagues at the University of New South Wales summarise the key study findings, including:

• Overnight wear remains the major risk factor for MK and increases risk by approximately four times
• Old storage cases, not cleaned properly or air-dried, increase MK risk
• Daily disposables have a low rate of serious MK when used on a strict daily wear schedule
• Timely diagnosis and appropriate treatment are of the utmost importance

The authors recommend that the two factors that have the highest impact on risk of disease be communicated to directly to contact lens wearers: overnight wear and poor case hygiene, irrespective of lens type. The magnitude of risk should also be known so that so wearers can make informed and responsible choices about the way contact lenses are used.

CLICK HERE TO ACCESS THE PAPER

 

Protective effects of UV-blocking contact lenses

Chandler HL, Reuter KS, Sinnott LT et al. Prevention of UV-induced damage to the anterior segment using Class I UV-absorbing hydrogel contact lenses. Invest Ophthalmol Vis Sci 2010; 51:172-178.

UV-blocking contact lenses protect the cornea, aqueous and crystalline lens from UV-induced damage, according to a new study published in Investigative Ophthalmology & Visual Science.

Twelve subjects were assigned to one of three treatment groups: senofilcon A (Acuvue Oasys, class I UV blocking) contact lenses; lotrafilcon A contact lenses (Focus Night & Day, no reported UV blocking); no contact lens. The contralateral eye was patched without a contact lens. UV-B exposure was applied daily for 5 days. Results showed:

• Significant increase in exposed corneas in MMP-2 and -9 (which degrade basement membrane), and TUNEL-positive cells and caspase-3 activity (indicating induction of cell death), in lotrafilcon A group compared with senofilcon A group
• Significant decrease in aqueous ascorbate (which may protect against cataract) in exposed lotrafilcon A group versus senofilcon A group
• Significantly increased caspase-3 activity in exposed crystalline lenses in lotrafilcon A group compared with senofilcon A group
• Increased TUNEL-positive cells in lotrafilcon A and non-contact lens groups

The authors conclude that senofilcon A class I UV-blocking contact lenses are capable of protecting the cornea, aqueous humour, and crystalline lens in an animal model from UV-induced pathologic changes.

CLICK HERE TO ACCESS THE PAPER

 

Spectacle correction increases peripheral hyperopic error

Lin Z, Martinez A, Chen X et al. Peripheral defocus with single-vision spectacle lenses in myopic children. Optom Vis Sci 2010;87:1 4-9.

Understanding myopic progression has moved a step closer with the finding that single-vision spectacle correction for myopia can result in increased hyperopic defocus at the peripheral retina in the eyes of Chinese children.

A study published in Optometry and Vision Science looked at 28 children (8 to 15 years) in two groups: low myopia (sph equivalent -0.75D to -3.00D) and moderate myopia (sph equivalent -3.25D to -6.00D). Cycloplegic autorefraction (RE) was measured at the fovea and at 20, 30, and 40° in the temporal and nasal visual fields. Measurements were taken on each subject while uncorrected and while wearing single-vision spectacle lenses (SVLs). Results demonstrated:

• Hyperopic peripheral defocus with SVLs in both groups
• An increase in relative peripheral hyperopic defocus when wearing SVLs compared with the uncorrected state, statistically significant for moderate myopes only
• In the moderate myopia group, relative peripheral hyperopic defocus was statistically significantly greater when wearing SVLs compared to the low myopia group at 40° in the nasal field and at both 30 and 40° in the temporal field

The authors conclude that increased peripheral hyperopic defocus tends to escalate with increasing refractive error and eccentricity, especially with moderate levels of myopia. They say a correcting lens that reduces or eliminates peripheral hyperopic defocus may have advantages over current corrections.

CLICK HERE FOR FULL ABSTRACT AND FULL TEXT

 

Peroxide disinfection has lowest adverse event rate with SiHs

Carnt NA, Evans VE, Naduvilath TJ et al. Contact lens-related adverse events and the silicone hydrogel lenses and daily wear care system used. Arch Ophthalmol 2009;127:12 1616-1623.

The incidence of adverse events in silicone hydrogel (SiH) lens daily wear varies by lens type and lens-solution combination, but is lowest with hydrogen peroxide disinfection, according to a study by Australian researchers.

A total of 558 myopic subjects took part in one or more of 40 participant trials in a matrix of 20 SiH contact lens and lens-solution combinations. Visits were at baseline, 2 weeks, 1 month, and 3 months. Adverse events were reported as the first occurrence of each event per 100 participant-months for each lens-solution combination. Rates per 100 participant-months were:

• 3.1 for all corneal infiltrative events (CIEs) and 1.7 for symptomatic CIEs
• Substantially different among solution groups for CIEs, with hydrogen peroxide having the lowest rate (0.6)
• 0.8 for superior epithelial arcuate lesions (SEALs), which varied by lens type but not by solution, and 0.4 for contact lens papillary conjunctivitis (CLPC), which varied by solution but not by lens type
• 4.7 for solution-induced corneal staining (SICS) for all lens-solution combinations and varied significantly based on lens-solution combination, with hydrogen peroxide having the lowest rate

The authors conclude that lens material and design, type of solution, and solution-lens interactions are likely contributing factors to the rate of adverse events in this mode of lens wear.

CLICK HERE TO ACCESS THE ABSTRACT

 

New methods for assessing toric soft lens stability

McIlraith A, Young G and Hunt C. Toric lens orientation and visual acuity in non-standard conditions. Contact Lens Ant Eye 2010; 33:1 23-26.

Toric soft contact lenses are usually assessed with the eyes in the primary position of gaze but this does not reflect the wearer’s range of eye movements and postural positions during a typical day’s wear.

A new UK study evaluates the effect of gravity and gaze direction on toric lens orientation and visual acuity (VA). Fourteen subjects wore each of four lens types: Acuvue Oasys for Astigmatism (AOfA), PureVision Toric (PVT), Air Optix for Astigmatism (AOT) and Proclear Toric (PCT). Lens orientation and VA were first assessed in the upright position and compared with those in a recumbent position. Toric lens orientation was then video-recorded in the eight cardinal directions of gaze. Results showed:

• All lenses rotated as a result of change in posture and head position
• In recumbent position mean rotation ranged from 11.0° (AOfA) to 29.1° (PCT).
• Mean reduction in VA ranged from 0.05 logMAR (AOfA) to 0.15 logMAR (PVT) and was significantly worse with PVT and PCT than with AOfA
• Lenses tended to rotate nasally with superior versions and temporally with temporal, nasal and inferior versions
• AOfA showed less rotation on inferio-nasal version than the other designs
• AOT showed significantly less rotation on superior-temporal version than PVT

The authors conclude that toric soft lens stability in extreme versions and postural positions can affect orientation and VA. These findings may help to explain some of the visual complaints reported by wearers, and also have implications for specific visual tasks such as reading and looking in the rear view mirror when driving.

CLICK HERE TO ACCESS THE ABSTRACT

 

Predicting dry eye symptoms in contact lens wearers

Pult H, Murphy PJ and Purslow C. A novel method to predict the dry eye symptoms in new contact lens wearers. Optom Vis Sci 2009:86:9 1042-1050.

What clinical signs and tests can best predict which patients are likely to experience dryness symptoms with soft contact lenses? A study from researchers at Cardiff University, published in Optometry & Vision Science, provides useful guidance.

The study investigates whether a combination of lid wiper epitheliopathy (LWE) and lid parallel conjunctival folds (LIPCOF) plus other tear film tests and subjective evaluation before contact lens fitting could predict contact lens-induced dry eye.

Signs and tests were investigated in 33 new soft contact lens wearers. Symptoms were evaluated by the Ocular Surface Disease Index (OSDI) and subjects grouped according to their response to a Contact Lens Dry Eye Questionnaire (20 symptomatic and 13 asymptomatic). Subjects were fitted with vifilcon A (Focus Visitint) and senofilcon A (Acuvue Oasys) lenses for a 2-week period, consecutively.

Among the findings were:

• LIPCOF non-invasive break-up time (NIBUT), and OSDI were better predictors than hyperaemia, tear meniscus height, phenol red thread test, staining, and LWE
• Limbal hyperaemia decreased in senofilcon A lenses
• Wearing comfort among symptomatic wearers was better with senofilcon A
• Subjects who became symptomatic had decreased NIBUT and increased LIPCOF and OSDI at enrolment

The authors say the best test combination to predict the development of contact lens-induced dry eye is NIBUT plus LIPCOF Sum (Nasal,+ Temporal grades) and OSDI. This combination of clinical tests has been named the Contact-Lens-Predicting-Test.

CLICK HERE TO ACCESS THE ABSTRACT CLICK HERE TO ACCESS THE OSDI

 

Myopia prevalence in US increases significantly in 30 years

Vitale S, Sperduto RD and Ferris FL. Increased prevalence of myopia in the United States between 1971-1972 and 1999-2004. Arch Ophthalmol 2009;127:12 1632-1639

The prevalence of myopia in the US has increased significantly since the 1970s, according to a study published in Archives of Ophthalmology.

The 1971-1972 National Health and Nutrition Examination Survey provided the earliest nationally representative estimates for US myopia prevalence. Using a similar method for diagnosing myopia, the authors examined data from the 1999-2004 survey to determine whether myopia prevalence had changed during the 30 years between the two surveys. Results showed:

• The estimated prevalence of myopia in persons aged 12 to 54 years was 66% higher in 1999- 2004 than in 1971-1972 (42% vs 25%)
• Prevalence estimates were higher in 1999-2004 than in 1971-1972 for all levels of myopia, although overall the prevalence of severe myopia was low
  Prevalence estimates increased by 64% for males and 69% for females
• The increase was greater for black individuals (33% vs 13%) than white individuals (43% vs 26%)
• Differences in prevalence between the two surveys remained statistically significant among those with 12 or more years of formal education

The authors observe that although myopia can be treated relatively easily with corrective lenses, the associated costs on a population basis are high. Identifying modifiable risk factors for myopia could lead to cost-effective interventional strategies, they say.

CLICK HERE TO ACCESS THE ABSTRACT OF THE PAPER

 

Poor vision in adults linked to early life and social factors

Rahi JS, Cumberland PM and Peckham CS. Visual function in working adults: early life influences and associations with health and social outcomes. Ophthalmology 2009;116:1866-71.

Impaired vision is associated with social factors such as unemployment, deprivation as well as poor health, according to a large-scale epidemiological study in the UK.

Researchers at the Institute of Child Health in London studied 9,330 adults aged 44 or 45 from the 1958 British cohort. They assessed distance, near and stereo acuities at medical examinations and recorded early life influences, and health and social outcomes in mid-adult life. They found that vision function was associated with:

• Unemployment resulting from permanent sickness
• Lower socioeconomic status
• Poorer general health
• Low birthweight or being small for gestational age
• Maternal smoking in pregnancy
• Socioeconomic deprivation in childhood

The authors highlight the importance of investigating visual function in the wider context of health and social functioning. Life-course epidemiology may prove valuable in revealing how such factors contribute to chronic eye disease in adult life.

CLICK HERE TO ACCESS THE ABSTRACT OF THE PAPER

 

US optometrists to advise patients at risk of AMD on nutrition

Nutrition counselling in the optometric practice. Optometry, 2009:80:10 587-9.

Nutrition counselling may soon be routine for optometrists in the US following new guidelines on the care of patients with age-related macular degeneration (AMD).

Among several articles on nutrition and eye health in its journal Optometry, the American Optometric Association says clinical practice guidelines to be issued early in 2010 will call on optometrists to advise patients on the benefits of proper nutrition.

The recommendations will be based on evidence from the Age-Related Eye Disease Study (AREDS) that antioxidant vitamins and minerals, taken in high doses by mouth, can reduce the progression to advanced AMD by 25% and the risk of moderate vision loss by 19% in specific patients, over a five-year period.

The study recommended that patients at risk supplement their diets daily with the AREDS nutritional formulation

• 500 mg of vitamin C
• 400 IU of vitamin E
• 15 mg of beta-carotene
• 80 mg of zinc oxide

The formulation also calls for patients to take 2 mg of copper per day, because zinc supplements interfere with copper absorption. Research since the AREDS study suggests that the nutrients lutein and zeaxanthin, and the omega-3 fatty acids DHA and EPA, might also be beneficial.

Other articles in this issue of Optometry include a review of macular pigment and healthy vision, and a summary of what patients should know about nutrition.

CLICK HERE FOR THE FULL TABLE OF CONTENTS CLICK HERE FOR THE AREDS STUDY FROM 2001

 

Presbyopic contact lenses, spectacles and driving performance

Chu BS, Wood JM and Collins MJ. Influence of presbyopic corrections on driving-related eye and head movements. Optom Vis Sci 2009;86:11 E1267-E1275.

Driving is one of the most demanding of all visual tasks and requires special consideration in presbyopes. An Australian study published in Optometry & Vision Science reveals some surprising differences between presbyopic vision corrections when viewing and responding to driving-related traffic scenes.

Twenty presbyopes (mean age 56 years) with no experience of presbyopic correction other than single vision (SV) reading spectacles each wore: distance SV lenses, progressive addition spectacles (PAL), bifocal spectacles (BIF), and monovision (MV) and multifocal contact lenses (MTF CL).

With each correction, subjects viewed video recordings of traffic scenes, tracked a reference vehicle, and identified peripheral targets. Digital numerical displays were included as near visual stimuli (simulating speedometer and radio). Results showed:

• Path length of eye movements while viewing and responding to driving-related traffic scenes was significantly longer with BIF and PAL than MV and MTF CL
• Path length of head movements was greater with all spectacle corrections than with MV and MTF CL
• No significant differences between daytime and night-time data
• Target recognition and brake response times were not significantly affected by vision correction but accuracy identifying near peripheral targets was affected

The authors say that the longer path length of eye and head movements and greater number of saccades associated with spectacle presbyopic corrections may affect driving performance by having a negative effect on attention and reaction times.

CLICK HERE TO ACCESS THE ABSTRACT OF THIS PAPER

 

Do dry eye treatments work and which type is most effective?

Doughty MJ and Glavin S. Efficacy of different dry eye treatments with artificial tears or ocular lubricants: a systematic review. Ophthal Physiol Opt 2009;29:6 573-583.

Do dry eye treatments work and which type is most effective? To address these questions, researchers at Glasgow Caledonian University reviewed the outcome of 33 clinical studies published over a 20-year period.

The studies all used rose bengal staining (RB) as an outcome measure, carried out using the classic 0-9 grading scale, before and after the use of artificial tears or ocular lubricants for approximately 30 days. Results include:

• The mean pre-treatment RB score was 4.25, decreasing to 2.84 after treatment, ie a net change of -1.43
• With artificial tears (saline, hypromellose) the net change after one month of treatment was -0.95, with carbomer gels (polyacrylic acid) it was -1.33, and with hyaluronic acid (HA) products -2.10
• The greater change with HA was not associated with a lower final outcome score, but with higher pre-treatment scores

The authors conclude that treating dry eye with artificial tears or lubricants does improve the ocular surface condition. Assuming no improvement without intervention, 30 days’ treatment will produce an overall improvement of around 25%, with little difference between types of treatment. Whether or not a further 25% improvement would occur over a second month of treatment remains unclear.

CLICK HERE TO VIEW THE ABSTRACT OF THE PAPER IN OPO

 

Single IOP reading masks short and long-term fluctuations

Sultan MB, Mansberger SL and Lee PP. Understanding the importance of IOP variables in glaucoma: a systematic review. Survey of Ophthalmol 2009;54:6 643-662.

Recent guidelines from the National Institute for Health and Clinical Excellence (NICE) have focused attention on the diagnosis and management of glaucoma and ocular hypertension. A major review from the US, published in the current issue of Survey of Ophthalmology, looks at some important aspects of intraocular pressure (IOP) measurement.

The paper reviews methods of IOP measurement, their validity and reliability. In particular, it summarises current knowledge of IOP changes over time and the potential impact of such changes on treatment. The authors conclude that:

• A single IOP measurement at a single visit is a poor indicator of IOP levels throughout the day and across visits
• Some attempt should be made to assess IOP at various times during the day and across visits
• Supine IOP measurement or IOP following water drinking may also provide an indication of the range of IOP fluctuation

The authors also suggest that the choice of treatment might be influenced by short or long-term fluctuations in IOP. They conclude that more studies are needed to better understand the value of assessing these changes and their role in the progression of glaucoma.

CLICK HERE TO ACCESS THE ABSTRACT CLICK HERE FOR A QUICK REFERENCE GUIDE TO THE NICE GUIDELINES CLICK HERE FOR THE LATEST GUIDANCE ON REFERRAL OF GLAUCOMA SUSPECTS

 

The Portsmouth corneal ulcer study

Ibrahim YW, Boase DL and Cree IA. Epidemiological characteristics, predisposing factors and microbiological profiles of infectious corneal ulcers: the Portsmouth corneal ulcer study. Br J Ophthalmol 2009;93:1319-1324.

Education is the key to reducing the rate and severity of infectious corneal ulcers, according to a new UK study published in the October issue of the British Journal of Ophthalmology.

Researchers reviewed the records of 1,786 patients with infectious corneal ulcers presenting at the eye casualty department of Queen Alexandra Hospital in Portsmouth over a 7-year period between January 1997 and December 2003. These cases accounted for 3% of total ophthalmic attendees. Among the findings were:

• Contact lens wear was the main predisposing factor, occurring in about three in 10 patients (31%)
• Other important risk factors included ocular diseases (24%), ocular trauma (6%) and systemic diseases (5%), or mixed factors (15%)
• A majority of the bacterial isolates (71%) were Gram-positive bacteria
• Nine out of 11 patients with Acanthamoeba keratitis wore contact lenses
• Most patients (97%) sought medical help more than once
• Only 34 patients (1.9%) had a poor visual outcome
• Follow-up, which reflects the duration of resolution, averaged 11.5 days

The authors note that there has been a declining trend in the rate of contact lens-related keratitis since the late 1990s, although contact lens wear remains the most important risk factor. They conclude that reducing the rate and severity of infectious corneal ulcers requires continuous education of patients, and of professionals.

CLICK HERE TO ACCESS THE ABSTRACT OF THE PAPER

 

TVCI survey finds more education needed on value of staining

Davies IP and Veys J. The use of fluorescein in contact lens aftercare. Contact Lens Ant Eye 2009 32:4 187-9.

Research among more than 2,000 contact lens practitioners attending THE VISION CARE INSTITUTE™ has shown that many practitioners do not routinely use fluorescein at soft contact lens aftercare visits.

Ian Davies and Jane Veys analysed responses from practitioners from five European countries/regions attending courses at the Institutes in Prague and Milan between July 2006 and March 2008. Participants were asked:

• How often do you stain soft contact lens wearers with fluorescein?
• How much corneal staining do you estimate you see in soft daily wear users?

Interactive voting by 2,116 practitioners choosing from four answer options revealed:

• The UK was the only group in which over half of respondents claimed to use fluorescein at each visit, 75% saying they used it ‘always’ or ‘most of the time’
• Most respondents, with the exception of the UK sample, did not routinely use fluorescein during soft lens aftercare
• Usage did not increase over the study period
• In general, countries that reported using fluorescein the most also reported seeing the highest incidence of corneal staining

The authors argue that concerns about lens discolouration and the risk of infection from fluorescein instillation are unfounded in modern contact lens practice. Education on the value of staining is needed if more practitioners are to use fluorescein more often.

This article was published in Contact Lens and Anterior Eye, and the full text of the paper can be accessed on the link below, with kind permission from Elsevier.

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Patients wearing contact lenses for spectacle dispensing spend more

Atkins NP, Morgan SL and Morgan PB. Enhancing the Approach to Selecting Eyewear (EASE): A multi-centre, practice-based study into the effect of applying contact lenses prior to dispensing. Cont Lens Ant Eye 2009 32:3 103-107.

This practice –based study demonstrates that using contact lenses as an aid to spectacle dispensing can result in a higher spend on spectacles and more patients buying contact lenses. The authors recommend offering contact lenses to all suitable patients prior to spectacle dispensing to optimise the dispensing process and to provide an opportunity to try contact lenses.

CLICK HERE TO VIEW THE ABSTRACT AND ACCESS ABSTRACT OF THE PAPER

 

Eating oily fish curbs progress of macular disease

Chiu C-J, Klein R, Milton RC et al. Does eating particular diets alter risk of age-related macular degeneration in users of the age-related eye disease study supplements? Br J Ophthalmol 2009;93 1241-1246 published online 12 June 2009;

Eating regular portions of oily fish could help stave off the progression of age-related macular degeneration (AMD), according to the latest findings from the 8-year AREDS (Age Related Eye Disease Study)

A total of 2,924 eligible AREDS participants were randomly assigned to receive one of four regimes: 1) a daily oral placebo; or 2) antioxidants of vitamins C (500mg), E (400IU) and beta carotene (15mg); or 3) the minerals zinc (80mg) and copper (2mg); or 4) the antioxidants plus zinc. Results showed:

• Progression to both dry and wet AMD was 25% less likely among those eating a diet rich in omega-3 fatty acids (DHA or EPA).
• A high omega-3 diet combined with a low glycaemic index (GI) carbohydrate intake reduced the risk of progression to advanced disease even further, cutting it by 50%

The authors suggest that eating two to three servings of oily fish, such as salmon, tuna, mackerel and herring every week, would achieve the recommended daily intake of omega 3, cutting the risk of both early and late stage AMD.

CLICK HERE TO VIEW THE ABSTRACT AND ACCESS THE FULL TEXT