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. 2023 Sep 1;12(9):13.
doi: 10.1167/tvst.12.9.13.

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

Victor Opoku-Yamoah  1 , Lisa W Christian  1 , Elizabeth L Irving  1 , Deborah Jones  1 , Daphne McCulloch  1 , Kalpana Rose  1 , Susan J Leat  1
Affiliations

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

Victor Opoku-Yamoah et al. Transl Vis Sci Technol. .

Abstract

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.

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Conflict of interest statement

Disclosure: V. Opoku-Yamoah, None; L.W. Christian, None; E.L. Irving, Leat and Irving: 2020 US copyright. Copyright for Face and Non-Face visual acuity symbols (FaceVA). Leat SJ, Irving EL. Registration number VAu 1-411-289. Feb 21 2020. 2019 Canadian copyright. Copyright for Face and Non-Face visual acuity symbols (FaceVA). Leat SJ, Irving EL. Registration number 1160819. Jul 4th 2019; D. Jones, None; D. McCulloch, None; K. Rose, None; S.J. Leat, Leat and Irving: 2020 US copyright. Copyright for Face and Non-Face visual acuity symbols (FaceVA). Leat SJ, Irving EL. Registration number VAu 1-411-289. Feb 21 2020. 2019 Canadian copyright. Copyright for Face and Non-Face visual acuity symbols (FaceVA). Leat SJ, Irving EL. Registration number 1160819. Jul 4th 2019

Figures

Figure 1.
Figure 1.
Faces and House/circle symbols used as the WatDAT targets. Permission to use Patti Pics house symbols from Precision Vision.
Figure 2.
Figure 2.
Agreement of WatDAT HC with ETDRS. (A and B) Bland–Altman plots for WatDAT HC and ETDRS for the 3 and 5 distractors, respectively. The difference between the WatDAT and ETDRS is plotted against the mean of the WatDAT and ETDRS. (C and D) Scatterplots of WatDAT against ETDRS. LV, low vision; Simulated, simulated low vision; LLOA, lower limit of agreement; ULOA, upper limit of agreement.
Figure 3.
Figure 3.
Agreement of WatDAT Faces with ETDRS. (A and B) Bland–Altman plots for WatDAT Face and ETDRS for the 3 and 5 distractors, respectively. The difference between the WatDAT and ETDRS is plotted against the mean of the WatDAT and ETDRS. (C and D) Scatterplots of WatDAT against ETDRS. LV, low vision; Simulated, simulated low vision; LLOA, lower limit of agreement; ULOA, upper limit of agreement.
Figure 4.
Figure 4.
Agreement of Kay pictures and PL tests (Cardiff acuity cards and TAC) and with ETDRS. (A–C) Bland–Altman plots for Kay Pictures, Cardiff and TAC, and ETDRS, respectively. The difference between each test and ETDRS is plotted against the mean of each test and ETDRS. (D–F) Scatterplots of Kay pictures, Cardiff, and TAC against ETDRS. The horizontal line at 0.1 shows the participants with low vision or simulated LV who demonstrated VA of 6/7.5 or better with the Kay or PL tests. LV, low vision; Simulated, simulated low vision; LLOA, lower limit of agreement; ULOA, upper limit of agreement.
Figure 5.
Figure 5.
(A) ROC plots for WatDAT tests in comparison with ETDRS using a cut-off of ≤0.1 versus >0.1. A, Area under the curve. (B) Dot histogram. Filled circles (0) = those with normal VA based on ETDRS. Open circles (1) = those with reduced VA.
Figure 6.
Figure 6.
Test–retest repeatability for WatDAT tests and ETDRS. (A, B, D, and E) Bland–Altman plots for the test and retest of WatDAT HC 3 and 5 distractors and WatDAT Faces 3 and 5 distractors, respectively. (C) Bland–Altman plot for the test and retest of ETDRS. The difference between the test and the retest is plotted against the mean of the test and retest. LV, low vision; Simulated, simulated low vision; LLOA, lower limit of agreement; ULOA, upper limit of agreement.
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References

    1. Wallace DK, Repka MX, Lee KA, et al. .. Amblyopia preferred practice pattern. Ophthalmology . 2018; 125(1): P105–P142, doi:10.1016/j.ophtha.2017.10.008. - DOI - PubMed
    1. Maurer D. Critical periods re-examined: evidence from children treated for dense cataracts. Cogn Dev . 2017; 42: 27–36, doi:10.1016/j.cogdev.2017.02.006. - DOI
    1. American Optometric Association A. Clinical practice guidelines: pediatric eye and vision examination. Canadian Association of Optometrists Web site. Available at: https://opto.ca/document/aoa-cpg-pediatric-eye-and-vision-examination/. Updated 2018. Accessed January 13, 2023.
    1. Rydberg A, Ericson B, Lennerstrand G, Jacobson L, Lindstedt E.. Assessment of visual acuity in children aged 1 1/2-6 years, with normal and subnormal vision. Strabismus . 1999; 7(1): 1–24, doi:10.1076/stra.7.1.1.656. - DOI - PubMed
    1. Leat SJ, Yakobchuk-Stanger C, Irving EL.. Differential visual acuity – a new approach to measuring visual acuity. J Optom . 2020; 13(1): 41–49, doi:10.1016/j.optom.2019.04.002. - DOI - PMC - PubMed

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