Comparing a traditional single optotype visual acuity test with a computer-based visual acuity test for childhood amblyopia vision screening: a pilot study

Home-based screening tools for amblyopia: a systematic review

Amblyopia is an important public health concern. While home-based screening may present an effective solution, this has not been rigorously assessed in a systematic review. A systematic review was performed using Ovid MEDLINE, PubMed, The Cochrane Library, Embase, Web of Science Core Collection, and Clinicaltrials.gov. All studies reporting the diagnostic accuracy of home-based screening tools for amblyopia among children were included. Studies involving orthoptist or ophthalmologist-led screening and adult subjects were excluded. The main outcome measure was the diagnostic accuracy expressed as sensitivity and specificity. Among 3670 studies identified, 28 were eligible for inclusion in our systematic review. The age range of patients were less than 1 month to 16 years old. 7 studies used internet-based tools, 16 used smartphone/tablet applications, 3 used digital cameras, and 3 used home-based questionnaires and visual acuity tools. All studies included a reference standard except one, which was a longitudinal study. 21 studies had full ophthalmological examination whilst 6 studies had validated visual acuity measurement tools as gold standards. Of the 27 studies which compared against a reference test, only 25 studies reported sensitivity and specificity values. Using the QUADAS-2 tool, 50% of studies were deemed to have applicability concern due to patient selection from tertiary centres and unclear methods for recruitment. There is a need to improve the quality of diagnostic accuracy studies, standardise thresholds for detecting amblyopia, and ensure consistent reporting of results. Further research is needed to evaluate the suitability of these tools for amblyopia screening.

Psychophysical Validation of a Novel Active Learning Approach for Measuring the Visual Acuity Behavioral Function

Purpose

To evaluate the performance of the quantitative visual acuity (qVA) method in measuring the visual acuity (VA) behavioral function.

Methods

We evaluated qVA performance in terms of the accuracy, precision, and efficiency of the estimated VA threshold and range in Monte Carlo simulations and a psychophysical experiment. We also compared the estimated VA threshold from the qVA method with that from the Electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) and Freiburg Visual Acuity Text (FrACT) methods. Four repeated measures with all three methods were conducted in four Bangerter foil conditions in 14 eyes.

Results

In both simulations and psychophysical experiment, the qVA method quantified the full acuity behavioral function with two psychometric parameters (VA threshold and VA range) with virtually no bias and with high precision and efficiency. There was a significant correlation between qVA estimates of VA threshold and range in the psychophysical experiment. In addition, qVA threshold estimates were highly correlated with those from the E-ETDRS and FrACT methods.

Conclusions

The qVA method can provide an accurate, precise, and efficient assessment of the full acuity behavioral function with both VA threshold and range.

Translational Relevance

The qVA method can accurately, precisely, and efficiently assess the full VA behavioral function. Further research will evaluate the potential value of these rich measures for both clinical research and patient care.

Comparison of the efficacy of Lea Symbol chart and Sheridan Gardiner chart for preschool vision screening

Purpose:

To compare the efficacy of Lea symbols (LS) chart and Sheridan Gardiner (SG) chart for vision screening among preschool children, in a semi-urban district of South India.

Methods:

Vision screening was conducted among 260 preschool children aged 3–5 years in cluster sampled kindergartens using LS chart and SG chart. Pass/fail scores and time taken for visual acuity (VA) estimation were compared. VA scores and time taken were compared using unpaired t-test. Sensitivity, specificity, and positive and negative predictive values were compared between the charts.

Results:

There was a significant difference between LS and SG charts in the VA score in both the eyes (P = 0.04). LS showed 76.09% pass score and 23.90% fail score, whereas SG showed 87.65% pass score and 12.35% fail score with a cutoff value of > 0.3 log MAR. Time for screening using LS was higher, when compared to SG, both for the right eyes (P < 0.001) and the left eyes (P < 0.001). The sensitivity of the LS was 94.74% (95% confidence interval [CI]: 70.13%–81.06%) and that of SG was 52.63% (95% CI: 45.29%–59.8%). The specificity of LS was 66.67% (95% CI: 90.26%–97.30%) and SG was 83.33% (95% CI: 70.12%–91.30%).

Conclusion:

LS chart showed better sensitivity and negative predictive value when compared to SG chart. However, SG chart showed better specificity and positive predictive value, and screening was less time-consuming. Considering the high sensitivity and negative predictive value, LS is the preferred tool, when compared to SG chart in preschool vision screening in our population.

Should tumbling E go out of date in amblyopia screening? Evidence from a population-based sample normative in children aged 3-4 years

Aims

To determine a normative of tumbling E optotype and its feasibility for visual acuity (VA) assessment in children aged 3-4 years.

Methods

A cross-sectional study of 1756 children who were invited to participate in a comprehensive non-invasive eye exam. Uncorrected monocular VA with crowded tumbling E with a comprehensive ophthalmological examination were assessed. Testability rates of the whole population and VA of the healthy children for different age subgroups, gender, school type and the order of testing in which the ophthalmological examination was performed were evaluated.

Results

The overall testability rate was 95% (92% and 98% for children aged 3 and 4 years, respectively). The mean VA of the first-day assessment (first-VA) and best-VA over 2 days’ assessments was 0.14 logMAR (95% CI 0.14 to 0.15) (decimal=0.72, 95% CI 0.71 to 0.73) and 0.13 logMAR (95% CI 0.13 to 0.14) (decimal=0.74, 95% CI 0.73 to 0.74). Analysis with age showed differences between groups in first-VA (F(3,1146)=10.0; p<0.001; η2=0.026) and best-VA (F(3,1155)=8.8; p<0.001; η2=0.022). Our normative was very highly correlated with previous reported HOTV-Amblyopia-Treatment-Study (HOTV-ATS) (first-VA, r=0.97; best-VA, r=0.99), with 0.8 to 0.7 lines consistent overestimation for HOTV-ATS as described in literature. Overall false-positive referral was 1.3%, being specially low regarding anisometropias of ≥2 logMAR lines (0.17%). Interocular difference ≥1 line VA logMAR was not associated with age (p=0.195).

Conclusions

This is the first normative for European Caucasian children with single crowded tumbling E in healthy eyes and the largest study comparing 3 and 4 years old testability. Testability rates are higher than found in literature with other optotypes, especially in children aged 3 years, where we found 5%–11% better testability rates.

Comparing visual acuity in preschool children using the Lea symbols and Sheridan Gardiner charts

Visual acuity measurement is a vital part of an optometric examination. The purpose of the present study was to compare visual acuity in preschool children using two charts – the Lea symbols chart and the Sheridan Gardiner chart. One hundred and fifty-three preschool children (72 boys and 81 girls) between the ages of 3 and 5 years (mean age and standard deviation 4.23 ± 0.78 years) were recruited from five randomly selected nursery schools. Distance visual acuity was measured monocularly and binocularly after a pre-test was done. An interval of 5 minutes was allowed for testing with both charts. The ages and sexes of each child were documented. Results showed a statistical difference in visual acuities using both charts (p < 0.05). There was also a statistical difference in both charts regarding age. There was no significant gender difference between the results from each chart.

Validity of a layperson-administered Web-based vision screening test

PURPOSE

To determine the sensitivity and specificity of the Web-based vision-screening test (WBT) VisionForKids.org when administered by an untrained layperson in a controlled environment.

METHODS

Visual acuities were obtained by an untrained layperson using the WBT under observation and by an ophthalmic professional using the Electronic Visual Acuity (EVA) Tester. Subjects were randomized to which method was used first. Subjects were considered to have failed by the following criteria: in children <48 months, 20/50 vision; in children between 48 and 59 months, 20/40 or worse; in children ≥60 months, 20/30 or worse. The results of the vision examinations by the WBT and the EVA Tester were compared; sensitivity and specificity of the WBT and the correlation coefficient to detect normal and abnormal vision compared to EVA testing were determined.

RESULTS

Visual acuities were obtained on 203 children between ages 3 and 12 years (average age, 7.4 years). Sensitivity of the WBT was 78.7% (95% CI, 66.0%-87.7%), specificity was 89.4% (95% CI, 82.9%-93.8%). The correlation coefficient of EVA testing with the WBT was 0.89 (P < 0.001).

CONCLUSIONS

This layperson-administered WBT, VisionForKids.org, is valid for identifying amblyopia in a controlled environment, making it possible for cost-effective and easily accessible vision screening to be performed by laypersons.

Reliability and validity of an automated computerized visual acuity and stereoacuity test in children using an interactive video game

PURPOSE

To evaluate the test-retest reliability and validity of the new automated computerized distance visual acuity and stereoacuity test for children, which uses an interactive video game.

DESIGN

Retrospective, observational case series.

METHODS

A total of 102 children aged between 3 and 7 years underwent the Snellen visual acuity test, the Distance Randot Stereotest, and the new automated computerized distance visual acuity and stereoacuity test. The test-retest reliability and validity of the automated computerized tests were assessed and compared with the Snellen visual acuity test and the Distance Randot Stereotest with frequency distributions of the differences, Bland-Altman plots, and Deming regression.

RESULTS

The automated computerized distance visual acuity test had high test-retest reliability (95% limits of agreement ±0.18 logMAR, 90.0% of the differences within 0.2 logMAR) and acceptable validity as compared with the Snellen visual acuity chart (95% limits of agreement ±0.27 logMAR, 81.3% of the differences within 0.2 logMAR). The automated computerized distance stereoacuity test had high test-retest reliability (95% limits of agreement ±0.29 log arc second, 95.1% of the differences within 0.3 log arc second) and acceptable validity as compared with the Distance Randot Stereotest (95% limits of agreement ±0.35 log arc second, 93.9% of the differences within 0.3 log arc second).

CONCLUSIONS

The new automated computerized distance visual acuity and stereoacuity test, which uses an interactive video game, has good reliability and acceptable validity compared with the Snellen visual acuity chart and the Distance Randot Stereotest.

A pilot trial of the iPad tablet computer as a portable device for visual acuity testing

We evaluated the accuracy of an app for the iPad tablet computer (Eye Chart Pro) as a portable method of visual acuity (VA) testing. A total of 120 consecutive patients (240 eyes) underwent visual acuity test with an iPad 2 and a conventional light-box chart. The logMAR VA results from the iPad were significantly higher than those from the light-box (P < 0.001). Bland-Altman analysis revealed a mean difference (bias) of 0.02 logMAR units between the VA results from the iPad chart and the light-box chart, with 95% limits of agreement of -0.14 to 0.19. Two groups of patients were defined: in Group 1 there were 182 eyes with VA better than 0.1 according to the light-box VA test. The median logMAR VA by the iPad was 0.54 and by the light-box chart it was 0.52; there was no significant difference between them (P = 0.69). In Group 2 there were 58 eyes with VA equal to or worse than 0.1 according to the light-box VA test. The median logMAR VA by the iPad was 1.26 and was 1.10 by the light box; the result from the iPad was significantly lower (P < 0.001). The Eye Chart Pro app installed on the iPad is reliable for VA testing only when the Snellen VA is better than 0.1 (20/200).

Vision test variability in retinitis pigmentosa and psychosocial factors

PURPOSE

We explored whether greater amounts of short-term variability in visual acuity (VA), contrast sensitivity (CS), or visual field (VF) in retinitis pigmentosa (RP) was related to disease severity or psychosocial factors.

METHODS

We obtained spectral domain-optical coherence tomography in 27 RP subjects and determined variability (SD) of VA, CS, and VF during a mean of 16 tests self-administered at home on a personal computer twice a week. Subjects completed the Positive and Negative Affect Schedules at each personal computer-test session, and SF-36 general health and Beck Depression Inventory questionnaires on one occasion.

RESULTS

There was a 0.10 log unit increase in VA variability for every 0.58 logMAR increase (worse mean VA) (p = 0.001). For subjects with reduced foveal thickness, mean VA explained more of the total VA variability than foveal thickness (R² = 0.72 and 0.46, respectively, in simple linear regressions). There was a statistically significant 4.3% increased log VF area variability for every 50% mean log VF area decrease (p < 0.001); explaining most of the total variability in log VF area variability (R² = 0.44). When controlling for mean log VF area, there was a statistically significant increase in log VF area variability for subjects with greater than minimal depressive symptoms (p = 0.015), with increased mean irritability scores (p = 0.02), decreased SF-36 physical functioning subscale scores (p = 0.03), or decreased mean score for feeling active, strong, and proud (p = 0.008) (adjusted R² = 0.62). CS variability was low and not statistically significantly related to mean CS, macular thickness, or psychosocial factors.

CONCLUSIONS

Increased VA and VF variability was predicted largely by increased RP severity. Greater VF variability occurred in subjects with reduced VF who reported less physical activity or increased negative psychosocial states. These associations should be considered during clinical examinations and trials for RP.