Development and validation of a new photographic scale to grade lid wiper epitheliopathy.

PURPOSE: Lid wiper epitheliopathy (LWE) is a clinical sign that has been associated with dry eye disease (DED) and contact lens discomfort (CLD). This study describes the development, validation and graders' preference of a new photographic scale for LWE, the Photographic Lid Wiper Epitheliopathy (PLWE) scale. METHODS: The PLWE grading scale was developed using LWE images selected from 57 screened patients (≥18 years of age) with confirmed LWE in both eyes. To validate the PLWE scale, a set including 20 images showing varying degrees of LWE from none to severe was chosen. To assess grading validity and grading reliability, observers were asked to grade the selected images using the PLWE and another commonly used subjective LWE grading protocol (Korb) on two separate sessions. RESULTS: The mean grade (±SD) of all images was not statistically significant different between the PLWE scale (1.55 ± 0.44) and the alternative grading scale (Korb, 1.47 ± 0.54) (ANOVA F1, p > 0.05). The average difference from the mean of all graders was 0.03 ± 0.53 using the PLWE scale and 0.06 ± 0.57 when using the Korb protocol (ANOVA F1, p > 0.05). The Coefficient of Repeatability was 1.04 and 1.12 for the PLWE and Korb scales (p > 0.05). Ninety-five percent of the graders found PLWE easier to use than Korb and the same percentage would consider using the PLWE scale in clinical practice. CONCLUSION: The format of the PLWE is similar to other anterior segment visual grading scales and this study revealed an ease of use preference for employing the PLWE by the graders. The presence of LWE has been associated with DED and CLD, and the addition of this new photographic scale could facilitate clinical judgement and record keeping of LWE in clinical practice.

Natural course of lid wiper epitheliopathy (LWE) in symptomatic contact lens wearers.

PURPOSE: To establish the time course of lid wiper epitheliopathy (LWE) in established CL wearers after a single day (6-10 h) of daily disposable contact lens (CL) wear, the following day post-CL removal and 1-week after CL discontinuation. METHODS: Twenty-one symptomatic (CLDEQ-8 score ≥ 12) habitual wearers of MyDay® silicone hydrogel daily disposable were included. LWE staining was assessed prior to CL wear (Visit 1, V1) using semi-automated analysis after instillation of two drops of 1 % lissamine green (10 µL) that were applied to the superior bulbar conjunctiva. LWE measurements were repeated after 6-10 h of continuous CL wear (Visit 2, V2), post-CL removal the following day (Visit 3, V3) and after 1-week CL discontinuation (Visit 4, V4). At each visit, ocular symptoms were evaluated using the SPEED-8 questionnaire and set of 0-100 visual analogue scales (VAS). RESULTS: LWE showed no significant changes after 6-10 h of continuous CL wear (p = 0.536), post-CL removal the following day (p = 0.677) or following 1-week of CL discontinuation (p = 0.478). Analysis revealed a significant improvement in symptomatology between V1 and V2 (SPEED-8, p < 0.01) and also improvements in the 0-100 VAS scores between V2 and V4 for average daily dryness (p < 0.01), end-of-day dryness (p < 0.01) and frequency of end-of-day dryness (p < 0.05). CONCLUSION: The present data suggest that the etiology of LWE is multifactorial and the sole intervention of temporarily discontinuing CL wear does not lead to resolution of these clinical signs.

The effect of the COVID-19 pandemic on working practices of UK primary care optometrists.

PURPOSE: In late 2019, a new coronavirus capable of infecting humans, SARS-CoV-2, was identified in Wuhan, China. The resultant respiratory disease was subsequently named COVID-19. In March 2020, in response to the COVID-19 pandemic, primary care optometry practices only remained open to deliver essential or emergency eye care. This study aimed to characterise the experiences of United Kingdom (UK)-based primary care optometrists during the COVID-19 pandemic. METHODS: An email invitation to participate in an online cross-sectional survey was sent to 3000 UK-based, currently practicing members of The College of Optometrists (UK). Responses to the structured questionnaire were analysed using descriptive statistics, including frequencies, means and standard deviations. Frequency analyses were used to evaluate items with multiple responses. Free-text responses were examined using thematic analyses. RESULTS: After data cleaning, a total of 1250 responses remained. Sixty-three percent were female, 70% self-identified as being of white ethnicity and 78% were based in England. During the first national lockdown, over half of all respondents were involved with the provision of remote consultations for emergency/urgent care. The majority felt 'very'/'moderately' comfortable conducting remote consultations, but 66% felt professional liability was increased. Forty percent were involved in the provision of face-to-face consultations. Eye-health and vision-related problems were the most commonly reported patient issues during both remote and face-to-face consultations, while contact-lens related problems were the least. Thematic analysis of the responses showed several challenges adjusting to the pandemic (e.g., working safely), but also some potential benefits (e.g., increased skills). CONCLUSIONS: The findings provide an overview of changes to optometric practice in the UK during the COVID-19 pandemic. The results may be used to inform the development of professional guidance and facilitate resource allocation for safe and effective eye care during this and any future pandemics.

Optimal methodology for lid wiper epitheliopathy identification.

PURPOSE: Lid wiper epitheliopathy (LWE) is a clinical sign that has been associated with dry eye disease. This study used a semi-automated method to identify the effect of drop instillation and post-dye viewing time on the absorption of lissamine green (LG) and sodium fluorescein (NaFl) on the upper eyelid in order to ascertain the optimal identification for LWE assessment. METHODS: In 37 participants with LWE, 1-drop of 1% LG (10 µL) was applied to the superior bulbar conjunctiva in the right eye, and photographs of the lid margin were taken 1, 3, and 5 min after instillation. Measurements were repeated in the same eye following instillations of 2-drops of 1% LG. The same procedures were followed for application of 2% NaFl (2 µL) to the left eye. Staining area was determined using software to detect and measure dye-stained images. Analysis used a linear mixed model with fixed effects of time, number of drops and their interaction. RESULTS: For LG, multivariate analysis showed that time of drop instillation was significant (p = 0.0091) as was the area of staining in the 2-drop versus 1-drop condition (p < 0.0001). For NaFl, there was a significant effect of time (p < 0.0001), drops (p < 0.0001), and a time/drops interaction (p < 0.0134), suggesting that both time and number of drops are important. CONCLUSION: A single drop of dye is insufficient to reveal the full extent of LWE staining. A 2-drop instillation is recommended and observation is recommended between 1 and 5 min (LG) and between 3 and 5 min (NaFl).

Impact of Improper Approach to Identify Lid Wiper Epitheliopathy (LWE).

PURPOSE: Variability in the use of ophthalmic dyes to diagnose lid wiper epitheliopathy (LWE) has led to division in the literature and clinical practice. The principal aim of this study was to evaluate whether the use of a non-optimal methodology to identify LWE had a potential for false negatives; in which LWE was overlooked. PATIENTS AND METHODS: A total of 20 participants were initially categorized to not have LWE and were enrolled in this study. The protocol examined whether or not LWE would later be revealed through the use of optimized methodology. Semi-automated analysis was performed of images taken after two different drop instillations with varying post-dye viewing times for both lissamine green (LG) and sodium fluorescein (NaFl). RESULTS: There was a significant increase in area of staining revealed when an optimal methodology for LWE identification was used. Comparisons for every non-optimal condition were statistically significantly different against the optimal condition (all p<0.01). The use of a non-optimal methodology resulted in a 70% false-negative rate when using LG and a 95% false-negative rate when using NaFl. CONCLUSION: The study demonstrated that using a double instillation of dye was statistically different from a single-dose, even with extended wait time for clinical observation. A single instillation did not offer adequate volume of dye for adequate lid margin uptake. A careful adherence to volume as well as a repeat administration is key to revealing the full area of LWE. A non-optimal approach to diagnose LWE can lead to false negatives.

Effect of stimulus configuration on crowding in strabismic amblyopia.

Foveal vision in strabismic amblyopia can show increased levels of crowding, akin to typical peripheral vision. Target-flanker similarity and visual-acuity test configuration may cause the magnitude of crowding to vary in strabismic amblyopia. We used custom-designed visual acuity tests to investigate crowding in observers with strabismic amblyopia. LogMAR was measured monocularly in both eyes of 11 adults with strabismic or mixed strabismic/anisometropic amblyopia using custom-designed letter tests. The tests used single-letter and linear formats with either bar or letter flankers to introduce crowding. Tests were presented monocularly on a high-resolution display at a test distance of 4 m, using standardized instructions. For each condition, five letters of each size were shown; testing continued until three letters of a given size were named incorrectly. Uncrowded logMAR was subtracted from logMAR in each of the crowded tests to highlight the crowding effect. Repeated-measures ANOVA showed that letter flankers and linear presentation individually resulted in poorer performance in the amblyopic eyes (respectively, mean normalized logMAR = 0.29, SE = 0.07, mean normalized logMAR = 0.27, SE = 0.07; p < 0.05) and together had an additive effect (mean = 0.42, SE = 0.09, p < 0.001). There was no difference across the tests in the fellow eyes (p > 0.05). Both linear presentation and letter rather than bar flankers increase crowding in the amblyopic eyes of people with strabismic amblyopia. These results suggest the influence of more than one mechanism contributing to crowding in linear visual-acuity charts with letter flankers.

Foveal crowding differs in children and adults.

We used custom-designed acuity tests to compare the magnitude and extent of crowded letter recognition in children and adults. Visual acuity (logMAR) was measured monocularly in children and adults using five custom-designed letter tests with varying degrees of crowding: single letter, single letter surrounded by four flanking bars, single letter surrounded by four flanking letters, line of five letters surrounded by flanking bars, and line of five letters surrounded by flanking letters. The tests were constructed using Sloan letters and presented on an iPad (Apple Incorporated, Cupertino, CA) at 4 m using a standardized endpoint and instructions. Crowded logMAR was normalized to unflanked logMAR and results were analyzed in three groups: younger children aged 4-6 (n = 32), older children, aged 7-9 (n = 30), and adults (n = 27). Both groups of children showed a greater extent of crowding than the adults. The adult participants showed no difference in performance between single or linear presentation and letter or bar flankers. Letter flankers and linear presentation individually resulted in poorer performance in the younger children p < 0.001 and p = 0.003, respectively (mean normalized logMAR 0.17 in each case) and together had an additive effect (mean 0.24), p < 0.001. Crowding in the older children was adult-like except in the linear presentation with letter flankers, p < 0.001. These results indicate that both target-flanker similarity and linear presentation contribute more to foveal crowding in young children than in adults.

Crowding in children's visual acuity tests--effect of test design and age.

PURPOSE: The aim of this study was to investigate the effect of test design (crowding) and age on visual acuity in a sample of young children. METHODS: Vision was measured in 103 children aged between 4 and 9 years using five different visual acuity tests. The tests included three crowded tests: logMAR Crowded test, the Sonksen logMAR test, and the Crowded Kay Picture test, and two single optotype tests: the Single Kay Picture and Sheridan Gardiner tests. Tests were presented in a random order using standardized instructions and a defined end-point. Results were analyzed in two age groups, younger (4 to 6 years) and older (7 to 9 years). RESULTS: In both groups, there was a significant main effect of test on acuity (younger: F = 63.92, dF = 4, p < 0.001; older: F = 63.59, dF = 4, p < 0.001). In the younger group, an effect of crowding was seen in all three crowded tests, but in the older group, an effect of crowding was seen only in the crowded letter tests. In both groups, mean acuity was lowest with the logMAR Crowded test, which has the closest interoptotype spacing (0.5), slightly higher with the Sonksen test (with interoptotype spacing of 1.0) and highest with the single optotype tests (no crowding). More crowding was seen in the younger children. CONCLUSIONS: Our results show that maturation of line acuity is still taking place between the ages of 4 and 9 years. Measured acuity is affected by the amount of contour interaction induced by the type of optotype (letter or picture) and by the interoptotype separation. Another factor, probably a maturation of gaze control or selective attention is responsible for the reduction in crowding with age.