Repeatability of SpotChecks contrast sensitivity test in macular disease

ABSTRACT Purpose SpotChecks is an accessible contrast sensitivity test with good repeatability in healthy adults. This study compared its intra‐visit repeatability with the near Pelli–Robson test in adults with macular disease. Methods One eye from 29 adults with macular disease (mean age 71 ± 13 years) underwent high‐contrast logMAR acuity and two repeated contrast sensitivity measurements with SpotChecks and Pelli–Robson during one visit. All testing was performed at 40 cm using habitual correction under 110 cd/m 2 luminance. SpotChecks was scored as the contrast sensitivity at the highest row with two or more errors. Pelli‐Robson was scored as (0.05 × the number of correct letters −0.15). Repeatability was defined as 1.96 w ( S w , within‐subject standard deviation), and differences between tests and groups were compared using a bootstrap hypothesis test. Limits of agreement between SpotChecks and Pelli–Robson were assessed with Bland–Altman analysis. Results were compared with previously tested healthy adults. Results Mean visual acuity was 0.15 ± 0.13 logMAR. Mean contrast sensitivity (logCS) was 1.51 ± 0.18 for SpotChecks, 1.49 ± 0.18 for Pelli‐Robson. Repeatability was identical for SpotChecks and Pelli–Robson (0.17 logCS, p = 0.98) and comparable to normal values (SpotChecks: 0.19 logCS, p = 0.53; Pelli–Robson: 0.17 logCS, p = 0.87). Contrast sensitivity correlated with logMAR acuity (SpotChecks: r = −0.60; Pelli–Robson: r = −0.48; both p < 0.001). Limits of agreement between SpotChecks and Pelli–Robson were 0.03 ± 0.21 logCS. Abnormal contrast sensitivity (>2 SD below normal) was detected in 76% of eyes with SpotChecks and 66% with Pelli–Robson, exceeding 34% identified by logMAR acuity ( p < 0.001 and p < 0.02, respectively). Conclusions In adults with macular disease and good to mildly reduced visual acuity, SpotChecks demonstrated intra‐visit repeatability comparable to Pelli–Robson and healthy individuals. Receiver operating characteristic analysis showed comparable discriminative performance for SpotChecks and Pelli–Robson, both outperforming high‐contrast logMAR acuity.