Do picture-based charts overestimate visual acuity? Comparison of Kay Pictures, Lea Symbols, HOTV and Keeler logMAR charts with Sloan letters in adults and children

Critical appraisal of Australian and New Zealand paediatric vision screening clinical practice guidelines using the AGREE II tool

CLINICAL RELEVANCE

Vision disorders in children impact health-related quality of life, with early detection and intervention improving outcomes and educational performance. Eye health professionals should be aware of paediatric vision screening guidelines and their development to understand the components of local programmes and the differences in sensitivity and specificity between protocols.

BACKGROUND

High-quality clinical practice guidelines (CPGs) for vision screening enable the early detection of common vision disorders; however, they require rigorous development to ensure optimal accuracy in detecting vision disorders, enabling timely interventions. This study evaluated the quality of available vision screening CPGs on vision screening of children in Australia and New Zealand.

METHODS

A systematic search of academic databases, guideline databases, professional associations and Google search engines was conducted to identify relevant paediatric vision screening CPGs. Four independent reviewers used the Appraisal of Guidelines, Research and Evaluation (AGREE II) instrument to assess the quality of individual guidelines and scores were aggregated and reported as the percentage of the total possible score across the six AGREE II domains: scope and purpose, stakeholder involvement, rigour of development, clarity of presentation, applicability, and editorial independence.

RESULTS

Initial 2,999 items were evaluated, with seven guidelines included. AGREE-II quality score agreement ranged from 43.3% to 95.8%. All guidelines scored >60.0% in the scope and purpose, however, most had poor scores of <26.5% in the rigour of development and <3.3% in editorial independence domains. All guidelines recommended screening using measures of habitual distance vision.

CONCLUSION

Of the guidelines developed for use in Australia and New Zealand, most guidelines scored poorly when assessed against the AGREE II tool, because of lack of editorial independence and rigour of development. Paediatric vision screening guidelines should prioritise systematic review of literature to inform practice and include statements regarding competing interests.

Developing a Novel Pediatric Eye Chart Assessing Visual Acuity by Minimum Separable Threshold

The purpose of this study was to develop a new pediatric acuity chart that can assess the minimum separation threshold by incorporating the minimum separation threshold into the picture. To overcome the design limitations of the Landolt ring, two designs of highly versatile minimum separable thresholds that can be easily incorporated into a picture were created: a black, filled circle (the "Circle") and a segment (the "Square"), both with the same break as in the Landolt ring. The three designs-the Landolt ring, Circle, and Square-were used to evaluate and compare the differences in the visual acuity of 21 healthy adults. No significant differences were observed between the results of the visual acuity tested with the Landolt ring, Circle, and Square (Landolt ring vs. Circle: p = 0.92, Landolt ring vs. Square: p = 0.31, Circle vs. Square: p = 0.40). The Bland-Altman analysis revealed no fixed errors between the Landolt ring and Circle and between the Landolt ring and Square (95% CI: -0.09-0.08, -0.09-0.12). Proportional errors were also not observed (p = 0.68, p = 0.41). The Landolt ring, Circle, and Square designs obtained equal results in visual acuity, thus achieving the successful development of a novel pediatric visual acuity chart using these designs.

Comparison of HOTV optotypes and Lea Symbols: a systematic review and meta-analysis

PURPOSE

To report the findings of our systematic review and meta-analysis comparing the completion time and testing time of visual acuity testing using Lea Symbols or HOTV optotypes.

METHODS

A systematic search of PubMed, SCOPUS, and CINAHL was conducted according to the PRISMA guidelines.

RESULTS

The completion rate for HOTV optotypes and Lea Symbols visual acuity testing was reported for 7,948 patients (average age, 3.59 years; age range, 2-17; 49.96% females). The 3-year-olds' completion rate of HOTV was 74.09% (47.93%-93.29%), compared with a Lea Symbols completion rate of 77.80% (53.93%-94.57%). The 4-year-olds' completion rate was 88.20% (63.48%-99.73%) for HOTV and 90.118% (67.42%-99.90%) for Lea Symbols. In 3-year-olds, the mean testing time was 118.33 ± 6.54 seconds for HOTV and 120.33 ± 6.53 seconds for Lea Symbols (P < 0.0001). The difference in testing times in the 4-year-old age group was also statistically significant (86.98 ± 6.12 seconds for HOTV and 94.32 ± 6.57 seconds for Lea symbols) (P < 0.0001).

CONCLUSIONS

There was a statistically significant difference in the testing times between the HOTV optotypes and Lea Symbols in both the 3- and 4-year-old age groups; however, the difference of 2-7 seconds on average is unlikely to be clinically significant. Testing speed and completion rate improve with age for both tests.

Validation of the Waterloo Differential Visual Acuity Test (WatDAT) and Comparison With Existing Pediatric Tests of Visual Acuity

Purpose

The new Waterloo Differential Acuity Test (WatDAT) is designed to allow recognition visual acuity (VA) measurement in children before they can typically undertake matching tests. The study purpose was to validate WatDAT in adults with normal and reduced VA.

Methods

Eighty adults (18 to <40 years of age) participated (32 normal VA, 12 reduced VA, and 36 simulated reduced VA). Monocular VA was measured on two occasions in random order for WatDAT (versions with 3 and 5 distractors for Faces and Patti Pics house among circles), Lea Symbols, Kay Pictures and Patti Pics matching tests, Teller Acuity Cards, Cardiff Acuity Test, and Early Treatment Diabetic Retinopathy Study (ETDRS) letter chart. Pediatric tests were validated against ETDRS using limits of agreement (LoA), sensitivity, and specificity. The LoA for repeatability were also determined.

Results

WatDAT showed minimal bias compared with ETDRS, and LoAs, which were similar to pediatric matching tests (0.241-0.250). Both preferential looking tests showed higher bias and LoAs than ETDRS. Matching tests showed good agreement with ETDRS, except for Kay Pictures and Lea Uncrowded test, which overestimated VA. WatDAT showed high sensitivity (>0.96) and specificity (>0.79), which improved with criterion adjustment and were significantly higher than for the preferential looking tests. LoA for repeatability for WatDAT 3 Faces and WatDAT 5 Faces were comparable with the ETDRS.

Conclusions

WatDAT demonstrates good agreement and repeatability compared with the gold-standard ETDRS letter chart, and performed better than preferential looking tests, the alternative until a child can undertake a matching VA test.

Translational Relevance

Good validity of the Waterloo Differential Acuity Test was demonstrated in adults as a first step to showing its potential for detecting childhood visual disorders.

Discrimination of paediatric acuity test optotypes by 6-year-old children

PURPOSE

To compare the discrimination performance of 6-year-old children for optotypes from six paediatric visual acuity tests and to fit Luce's Biased Choice Model to the data to estimate the relative similarities and bias for each optotype.

METHODS

Full data sets were collected from 20 typically developing 6-year-olds who had passed a vision screening. They were presented with single optotypes labelled 6/12 at a distance of 9 m and were asked to identify the optotype using a matching task containing all optotypes from the relevant test. The data were combined to form a confusion matrix for each test and a biased choice model was fitted to the data.

RESULTS

Median correct performance varied from 40% to 100% across optotypes, with the HOTV test having the highest values. Estimates of the similarity of each pair of optotypes indicated equal values for all pairs in the Landolt C, HOTV, Lea numbers and Tumbling E tests. The values differed for the picture tests, that is Lea Symbols and Allen figures. The estimates of bias for each individual optotype also indicated different values with the picture tests.

CONCLUSIONS

Previous studies of the threshold acuity of young children and adults have indicated differences in acuity estimates across paediatric tests. A recognition acuity task typically requires resolving the difference information between optotypes. The performance of the 6-year-olds here reveals variance in similarity and bias values for picture tests, particularly for the Allen figures when compared with the Lea Symbols. Ideally, this analysis should be performed when designing new tests, and these results motivate progression from the use of current picture tests to well calibrated letter or number tests at the earliest possible age.

Acuity Comparison Methods via Timed Test-Retest Precision of Matching-Card e-ETDRS Compared to PDI Check in Treated Amblyopes and Superb Normals

Purpose

Existing and emerging visual acuity methods like dynamic and dichoptic presentation, preferential looking and eye tracking promise to afford better and earlier assessment in children with and without amblyopia so we propose methods needed to easily evaluate and compare their metrics.

Subjects and Methods

Patients older than 8 years with treated amblyopia and superb vision (logMAR -0.1 to -0.3) normals performed timed, patched eETDRS with Sloan matching card at 3.00 m and PDI Check dichoptic near rivalry dynamic test to demonstrate test re-Test and compared disparate acuity with intraclass correlation (ICC) and Bland Altman 95% limits of agreement (LOA) to generate a simple method of qualifying acuity test matching.

Results

26 amblyopic patients and 11 superb-vision normals performed eETDRS retest, PDI Check retest and combined ICC of 0.98, 0.60 and 0.27, respectively, and Bland Altman LOA of 0.24, 2.06 and 2.28 logMAR. The time to test one eye with eETDRS had median (interquartile range; IQR) duration of 280 (205 to 346) seconds, while the PDI Check autostereoscopic dichoptic for both eyes only took 39 (30 to 47) seconds. Optimum ICC and LOA for visual acuity comparison should be >0.95 and <0.3 logMAR, whereas "good" ICC and should be 0.75-0.89 ICC and 1.0-1.49 logMAR LOA.

Conclusion

Superb vision subjects (logMAR < -0.1) and treated amblyopic patients confirmed optimum comparable eETDRS, and fair test re-Test PDI Check but suppression on near dichoptic testing confirmed disparity compared to optimized eETDRS distance acuity.

Preliminary clinical validation of a new picture-based visual acuity test in children with amblyopia: a comparison of The Auckland Optotypes and crowded logMAR letters

BACKGROUND/AIMS

Amblyopia is the most common visual deficit in children and accurate visual acuity (VA) assessment is essential for diagnosis. While ETDRS high-contrast logMAR VA is the reference standard test for adults, less agreement exists for pre-literate children. A new picture optotype acuity test (The Auckland Optotypes [TAO]) has shown favourable comparison to letter acuity charts but has not yet been evaluated in children with amblyopia. This study aimed to compare VA obtained using TAO to crowded logMAR letters in children age 5-8 years with amblyopia.

METHODS

Children with amblyopia (n = 54 [20.37% strabismic, 18.52% anisometropic, 61.11% mixed], mean age 78.30 ± 11.72 months) were recruited from paediatric ophthalmology/orthoptic clinics at Moorfields Eye Hospital NHS Foundation Trust, London, and Cambridge Community Services NHS Trust, Bedford. Best-corrected VA was measured in both the amblyopic eye (AE) and fellow eye (FE) using TAO and a crowded letter acuity chart. Bland-Altman analysis was used to measure 95% limits of agreement (LoA) for VA measures captured (AE, FE and interocular difference [IOD]).

RESULTS

Good agreement between TAO and letter VA measurement was observed (mean bias: AE -0.01, FE 0.01, IOD -0.02). For AE measures 95% LoA were from -0.25 to 0.24 logMAR, this being similar for FE (-0.24 to 0.25) and IOD measures (-0.30 to 0.27).

CONCLUSION

TAO and letters elicited similar VA in children with amblyopia. TAO could be a useful picture-based chart for paediatric vision assessment.

Shortening the Early Treatment Diabetic Retinopathy Study visual acuity test utilizing a novel computer software: reproducibility in control and patient eyes

PURPOSE

To describe and compare a method of computerized visual acuity (VA) testing software to the Early Treatment Diabetic Retinopathy Study (ETDRS) chart.

METHODS

Setting: Single tertiary institution.

STUDY POPULATION

Prospective study including right eyes of volunteers (N = 109) and patients (N = 126).

INTERVENTION

Subjects were tested in a random order twice with the ETDRS chart and twice with the VA software. For ETDRS, we calculated the final VA separately for each run, using four different test termination criteria (1-miss in a row, 2-miss in a row, 50% miss and per-letter). For software testing, we calculated final VA with a variety of number of letters presented.

MAIN OUTCOME MEASURES

The main outcome measures were reproducibility and number of letters required to exceed ETDRS reproducibility.

RESULTS

For ETDRS, the average number of letters presented was 55.1 ± 9, 54.3 ± 10, 53.1 ± 10 and 70 for the 1-miss, 2-miss, 50% termination and per-letter criterion. The test-retest variability (TRV) of ETDRS was 0.29, 0.42, 0.17 and 0.141 for the 1-miss in a row, 2-miss in a row, 50% and per-letter termination criteria. For the software VA test, TRV was 0.202, 0.138 and 0.112 after presenting 6, 11 and 20 letters. The reproducibility of the software was equal to the ETDRS at 11 letters and thereafter surpassed. Similar results were achieved in the patient group.

CONCLUSIONS

This study demonstrates that by utilizing a VA testing software, based on advanced threshold testing algorithms we were able to duplicate, and surpass, the reproducibility of the ETDRS chart while presenting much fewer letters.

Diagnostic accuracy of the Parr vision test, single crowded Lea symbols and Spot vision screener for vision screening of preschool children aged 4-5 years in Aotearoa/New Zealand

PURPOSE

Preschool children in New Zealand undergo vision screening to detect amblyopia at 4-5 years of age. The current test, the Parr vision test, does not meet international visual acuity chart guidelines and has not been validated against other commonly used paediatric vision tests. New Zealand vision screening protocols are also not targeted for detecting other eye conditions such as uncorrected refractive error, which may affect school performance. We compared the Parr vision test with the single crowded Lea symbols and the Spot vision screener for detecting ocular pathology, refractive error and amblyopic risk factors in preschool children.

METHODS

A cross-sectional diagnostic accuracy study recruited children aged 4-5 years via convenience sampling from the University of Auckland Optometry Clinic and through primary schools in Auckland, New Zealand. Participants received vision screening with the three different instruments administered by a lay screener. Comprehensive eye examinations were completed by a paediatric optometrist to determine the presence of vision disorders.

RESULTS

Of 197 children who received a comprehensive eye examination, 14 (7.1%) had amblyopic risk factors and 43 (21.8%) had significant refractive error (15.7% with astigmatism, 9.1% with hyperopia). The sensitivity for detecting any ocular condition did not differ significantly between the tests (50.0% for Parr, 43.5% for Lea, 42.5% for Spot). Specificity was significantly lower for the Parr vision test (80.8%) than for the Lea symbols (93.4%) and Spot vision screener (98.0%). Adding the Spot vision screener to measurements of visual acuity significantly improved sensitivity in detecting any ocular condition with the Parr vision test (67.5% for Parr/Spot vs 50% for Parr alone), but not with the Lea symbols (52.5% for Lea/Spot vs 43.5% for Lea alone).

CONCLUSION

The sensitivity of the Parr vision test for detecting ocular conditions in preschool children does not vary significantly from that achieved by the Lea symbols or the Spot vision screener. However, current New Zealand vision screening protocols could be improved by expanding the target conditions to include significant refractive error and incorporating the use of the Spot vision screener to increase the accuracy with which children with refractive error are identified. Future research should include longitudinal studies to determine the effect of preschool vision screening on later ocular and academic outcomes.

Measurement of visual acuity with a digital eye chart: optotypes, presentation modalities and repeatability

PURPOSE

Digital or computerised eye charts are becoming standard in the examination of visual acuity. Each instrument allows the selection of different optotypes, presentation modalities, and crowding. The aim of this study was to examine the differences in visual acuity (VA) measurement using a digital eye chart, comparing different optotypes and procedures, together with an evaluation of the repeatability of the measurement.

METHODS

Two groups of 52 participants aged between 18 and 31 years participated in the study. In the first experiment, VA thresholds were measured using LEA Symbols, Tumbling E, and Landolt Rings in monocular and binocular conditions using single line presentation and QUEST presentation. In the second experiment, we have compared all modalities of presentation together with a paper eye-chart and test the repeatability.

RESULTS

The results showed that thresholds for LEA Symbols are low. The modality of presentation affects these thresholds. For Landolt Rings and Tumbling E, the QUEST procedure gave significantly better thresholds than line presentation, while this difference was absent for LEA Symbols. In comparing all modalities of presentation, single letter and line presentation showed similar values, slightly better than block presentation. Paper eye-charts showed better values of VA. Repeatability and agreement were good for all presentations, but best for QUEST.

CONCLUSIONS

The QUEST modality of presentation provides a better threshold than line presentation except for LEA Symbols. Examiners using digital eye charts must take into account that not all modalities of presentation and optotypes are equivalent and give different VA thresholds. Specific thresholds need to be used for each optotype and presentation modality.

Teleophthalmology: Evaluation of Phone-based Visual Acuity in a Pediatric Population

Purpose

With the recent rise of teleophthalmology due to coronavirus disease, health care needs accurate and reliable methods of checking visual acuity remotely. The visual acuity as measured by the GoCheck Kids application was compared with that of the Amblyopia Treatment Study (ATS) and the authors' clinic protocol.

Design

This was a prospective, comparison of visual acuity assessment methods.

Methods

Established patients (3-18 years of age) in the practice of a single pediatric ophthalmologist were eligible. Visual acuity was measured 1) by GoCheck Kids mobile application, by the patient's family member; 2) by HOTV-ATS, by study personnel; and 3) by regular clinic protocol, by an ophthalmic technician. To assess agreement between measurement of acuity, intraclass correlations with 95% confidence intervals (CI) were computed.

Results

A total of 53 children participated. The mean differences between GoCheck Kids and HOTV-ATS acuities (0.094) were significantly different (P < .001). The intraclass correlation coefficient (ICC) was 0.55 (95% CI: 0.40-0.68). The mean differences between GoCheck Kids and chart acuities (0.010) were not significantly different (P = .319; ICC: 0.59; 95% CI: 0.45-0.71). The mean differences between HOTV-ATS and chart acuities (0.084) were significantly different (P < .001; ICC: 0.66; 95% CI: 0.53-0.76). The percentages of eyes with visual acuity measured by GoCheck Kids within 1 line of the HOTV-ATS and chart acuity were 65.3% and 86.7%, respectively.

Conclusions

GoCheck Kids as checked by a family member provided a modest correlation of visual acuity compared to the chart screen and a fair correlation of visual acuity compared to HOTV-Amblyopia Treatment Study protocol, although most were within 1 line.

Grouping Effects on Foveal Spatial Interactions in Children

Purpose

Grouping of flankers from the target can modulate crowding in adults. Visual acuity in children is measured clinically using charts with targets and different flankers to enhance spatial interactions. We investigated grouping effects on interactions using visual acuity letters, flanked by contours and letters, in children.

Methods

Visual acuity for isolated and flanked letters was measured in 155 three- to 11-year old children and 32 adults. Flankers were one stroke width from the target and were a box or four bars and black or red letters. Magnitudes of interaction were flanked minus isolated logMAR acuities. Psychometric function slopes were also examined.

Results

Magnitudes of interaction by contours did not change significantly with age. They were 0.047 ± 0.014 logMAR more with bars than a box. Interaction from flanking letters reduced with age, adults being not different from 9- to 11-year-olds for black and red letter surrounds. It was weaker by 0.033 ± 0.013 logMAR when a black letter was surrounded by red rather than black letters. Psychometric function slopes for visual acuity were steepest for the youngest children (3-5 years).

Conclusions

For contour and letter flankers, grouping effects on interaction magnitude are age independent. Grouping bars into a box forming a single object reduces magnitude of effect. Grouping letter flankers by color and ungrouping them from the target reduce interaction magnitude by ∼8%, suggesting that luminance-defined form dominates. Differently colored letter flankers of high-luminance contrast on acuity charts could draw attention to the target but retain significant interaction strength.

Refractive Errors and Amblyopia Among Children Screened by the UCLA Preschool Vision Program in Los Angeles County

PURPOSE

To summarize the results of 5 years of vision screening with the University of California, Los Angeles (UCLA) Preschool Vision Program (UPVP).

DESIGN

Retrospective evaluation of a screening program.

METHODS

The UPVP performed visual acuity and undilated noncycloplegic refractive screening using an autorefractor on 93,097 children between 2012 and 2017. Of these, 79,451 children, who were between 3 and 5 years old, were screened for the first time, and 14,259 were referred for full cycloplegic examination if they met specific refractive criteria for myopia, hyperopia, astigmatism, or anisometropia. UPVP performed 6779 cycloplegic examinations on this population. Data from the right eye only were included in this analysis.

RESULTS

Of the examined population, hyperopia was found in 61% (4018), myopia in 20% (1336), and astigmatism in 93% (6122) of children. Latino children had higher rates of astigmatism and worse visual acuity compared to all other races/ethnicities. An astigmatism cutoff of ≥1.50 diopters (D) in either eye correctly predicted the need for glasses 93% of the time; increasing this cutoff to ≥1.50 D in both eyes increased the positive predictive value to 96%. Refractive amblyopia was found in 780 children (1.0% of the screened population and 11.5% of the examined population), and of these, 211 (27%) were bilaterally amblyopic.

CONCLUSIONS

These data represent the largest published sample of vision screening results on preschool-aged children, provide additional insight on the proportion of common refractive errors and their association with race/ethnicity, and can inform screening criteria to more accurately identify children who need intervention to prevent permanent vision loss.

Differential visual acuity - A new approach to measuring visual acuity

BACKGROUND

A novel type of acuity measurement, which we refer to as 'differential acuity', requires the observer to identify one unique target among three others which are identical. This is a proof of concept study aimed to determine if differential acuity is equivalent to standard measures of recognition acuity.

METHODS

To create a range of visual acuity, vision was optically blurred in sixteen adults with normal visual acuity. Visual acuity was then measured with the differential acuity targets in both crowded and uncrowded format, and compared with standard ETDRS acuity or with singly presented letters and uncrowded letters were analysed separately.

RESULTS

The visual acuity results for crowded and uncrowded letters were analysed separately. Repeated measures analysis of variance showed that when a crowded Sloan C had to be differentiated from three crowded Os (CvsO), the results were not significantly different from ETDRS acuity or from naming one of four letters presented centrally (Name4) (p<0.05). Similar results were found for uncrowded letters - the C versus O and Name4 gave similar visual acuity. The 95% limits of agreement between the naming and C versus O differential acuity measures were between 0.17 and 0.27 logMAR.

CONCLUSION

From this proof of concept study we conclude that differential acuity gives similar results to the ETDRS chart in adults. We infer that the comparable but cognitively simpler differential visual acuity task could be applied in clinical settings for young children or patients with developmental delay who cannot respond by naming or matching.

Agreement on the use of sensory screening techniques by nurses for older adults with cognitive impairment in long-term care: a mixed-methods consensus approach

OBJECTIVE

Based on two scoping reviews and two environmental scans, this study aimed at reaching consensus on the most suitable sensory screening tools for use by nurses working in long-term care homes, for the purpose of developing and validating a toolkit.

SETTING

A mixed-methods consensus study was conducted through two rounds of virtual electronic suitability rankings, followed by one online discussion group to resolve remaining disagreements.

PARTICIPANTS

A 12-member convenience panel of specialists from three countries with expertise in sensory and cognitive ageing provided the ranking data, of whom four participated in the online discussion.

OUTCOME MEASURES

As part of a larger mixed-methods project, the consensus was used to rank 22 vision and 20 hearing screening tests for suitability, based on 10 categories from the Quebec User Evaluation of Satisfaction with Assistive Technology questionnaire. Panellists were asked to score each test by category, and their responses were converted to z-scores, pooled and ranked. Outliers in assessment distribution were then returned to the individual team members to adjust scoring towards consensus.

RESULTS

In order of ranking, the top 4 vision screening tests were hand motion, counting fingers, confrontation visual fields and the HOT-V chart, whereas the top 4 hearing screening tests were the Hearing Handicap Inventory for the Elderly, the Whisper Test, the Measure of Severity of Hearing Loss and the Hyperacusis Questionnaire, respectively.

CONCLUSIONS

The final selection of vision screening tests relied on observable visual behaviours, such as visibility of tasks within the central or peripheral visual field, whereas three of the four hearing tests relied on subjective report. Next, feasibility will be tested by nurses using these tools in a long-term care setting with persons with various levels of cognitive impairment.