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

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.

The Waterloo Differential Acuity Test ( WatDAT )—Testability and normative data

“…Several other studies have reported that the Kay Picture test overestimates VA compared to ETDRS by 1 to 2 lines 38–42 . This is consistent with the present data and with Opoku‐Yamoah et al 20 …”

“… 38 , 39 , 40 , 41 , 42 This is consistent with the present data and with Opoku‐Yamoah et al. 20 —both of these studies used the newly redesigned Kay Picture test.…”

“…Comparing the binocular levels of VA reported in the present study, it is worthwhile noting that the two versions of the WatDAT gave results which were not significantly different. This was consistent when validated against the ETDRS chart in adults—both gave similar, slightly poorer logMAR VA (positive bias) of about 3.5 letters (0.07 logMAR) compared to ETDRS 20 . In comparison, in adults, the uncrowded Patti Pics matching showed almost no bias compared to ETDRS while the Kay Picture test gave VAs which were nearly two lines better than ETDRS.…”

“…It is also important to note that all of these children obtained 0.00 logMAR with the Cardiff Acuity Test, and yet some showed potential deficits with WatDAT (e.g., Participants 1, 7 and 8). This re‐emphasises the importance of measuring recognition VA whenever possible 20 …”

“… 6 Validation of the WatDAT has been undertaken in adults by measuring agreement with the gold‐standard Early Treatment of Diabetic Retinopathy Study (ETDRS) test. 20 The WatDAT showed good agreement with the ETDRS and similar repeatability. It also showed high sensitivity and specificity (>94%) to detect reduced ETDRS acuity.…”

The Waterloo Differential Acuity Test ( WatDAT )—Testability and normative data

“…Several other studies have reported that the Kay Picture test overestimates VA compared to ETDRS by 1 to 2 lines 38–42 . This is consistent with the present data and with Opoku‐Yamoah et al 20 …”

“… 38 , 39 , 40 , 41 , 42 This is consistent with the present data and with Opoku‐Yamoah et al. 20 —both of these studies used the newly redesigned Kay Picture test.…”

“…Comparing the binocular levels of VA reported in the present study, it is worthwhile noting that the two versions of the WatDAT gave results which were not significantly different. This was consistent when validated against the ETDRS chart in adults—both gave similar, slightly poorer logMAR VA (positive bias) of about 3.5 letters (0.07 logMAR) compared to ETDRS 20 . In comparison, in adults, the uncrowded Patti Pics matching showed almost no bias compared to ETDRS while the Kay Picture test gave VAs which were nearly two lines better than ETDRS.…”

“…It is also important to note that all of these children obtained 0.00 logMAR with the Cardiff Acuity Test, and yet some showed potential deficits with WatDAT (e.g., Participants 1, 7 and 8). This re‐emphasises the importance of measuring recognition VA whenever possible 20 …”

“… 6 Validation of the WatDAT has been undertaken in adults by measuring agreement with the gold‐standard Early Treatment of Diabetic Retinopathy Study (ETDRS) test. 20 The WatDAT showed good agreement with the ETDRS and similar repeatability. It also showed high sensitivity and specificity (>94%) to detect reduced ETDRS acuity.…”

The Waterloo Differential Acuity Test ( WatDAT )—Testability and normative data

“…Several other studies have reported that the Kay Picture test overestimates VA compared to ETDRS by 1 to 2 lines 38–42 . This is consistent with the present data and with Opoku‐Yamoah et al 20 …”

“… 38 , 39 , 40 , 41 , 42 This is consistent with the present data and with Opoku‐Yamoah et al. 20 —both of these studies used the newly redesigned Kay Picture test.…”

“…Comparing the binocular levels of VA reported in the present study, it is worthwhile noting that the two versions of the WatDAT gave results which were not significantly different. This was consistent when validated against the ETDRS chart in adults—both gave similar, slightly poorer logMAR VA (positive bias) of about 3.5 letters (0.07 logMAR) compared to ETDRS 20 . In comparison, in adults, the uncrowded Patti Pics matching showed almost no bias compared to ETDRS while the Kay Picture test gave VAs which were nearly two lines better than ETDRS.…”

“…It is also important to note that all of these children obtained 0.00 logMAR with the Cardiff Acuity Test, and yet some showed potential deficits with WatDAT (e.g., Participants 1, 7 and 8). This re‐emphasises the importance of measuring recognition VA whenever possible 20 …”

“… 6 Validation of the WatDAT has been undertaken in adults by measuring agreement with the gold‐standard Early Treatment of Diabetic Retinopathy Study (ETDRS) test. 20 The WatDAT showed good agreement with the ETDRS and similar repeatability. It also showed high sensitivity and specificity (>94%) to detect reduced ETDRS acuity.…”

The Waterloo Differential Acuity Test ( WatDAT )—Testability and normative data

“…Several other studies have reported that the Kay Picture test overestimates VA compared to ETDRS by 1 to 2 lines 38–42 . This is consistent with the present data and with Opoku‐Yamoah et al 20 …”

“… 38 , 39 , 40 , 41 , 42 This is consistent with the present data and with Opoku‐Yamoah et al. 20 —both of these studies used the newly redesigned Kay Picture test.…”

“…Comparing the binocular levels of VA reported in the present study, it is worthwhile noting that the two versions of the WatDAT gave results which were not significantly different. This was consistent when validated against the ETDRS chart in adults—both gave similar, slightly poorer logMAR VA (positive bias) of about 3.5 letters (0.07 logMAR) compared to ETDRS 20 . In comparison, in adults, the uncrowded Patti Pics matching showed almost no bias compared to ETDRS while the Kay Picture test gave VAs which were nearly two lines better than ETDRS.…”

“…It is also important to note that all of these children obtained 0.00 logMAR with the Cardiff Acuity Test, and yet some showed potential deficits with WatDAT (e.g., Participants 1, 7 and 8). This re‐emphasises the importance of measuring recognition VA whenever possible 20 …”

“… 6 Validation of the WatDAT has been undertaken in adults by measuring agreement with the gold‐standard Early Treatment of Diabetic Retinopathy Study (ETDRS) test. 20 The WatDAT showed good agreement with the ETDRS and similar repeatability. It also showed high sensitivity and specificity (>94%) to detect reduced ETDRS acuity.…”