PURPOSE. Visual acuity (VA) and contrast sensitivity (CS) characterize different aspects of visual function. Whereas VA is a standard test in routine eye exams and clinical trials, CS is often not included. We investigated the pathology-specific dissociation between VA and CS by quantifying and comparing the relationship between these two measures in common ocular pathologies. METHODS. VA and CS data were assembled from 1113 subjects, including groups with cataract (n = 450), age-related macular degeneration (AMD; n = 232), glaucoma (n = 100), retinitis pigmentosa (RP; n = 87), and normal ocular health (n = 244). VA and CS were measured by the Early Treatment Diabetic Retinopathy Study chart and Pelli–Robson chart, respectively. RESULTS. Even when VA was relatively normal (<0.3 logMAR), the four ocular pathology groups showed quantitatively different mean CS deficits relative to normal controls, ranging from –0.01 log units for cataract to 0.23 log units for RP. When the entire range of VA was considered, the corresponding deficits in CS were noticeably different across these four groups, being least for cataract and progressively more severe for glaucoma, AMD, and RP. For every 1.0 logMAR loss of VA, the corresponding deficit in CS ranged from 0.22 logCS for cataract to 0.97 logCS for RP. CONCLUSIONS. The quantitative relationship between VA and CS depends on the ocular pathology. CS appears to provide valuable complementary information to VA in the early detection of eye disease and when evaluating visual impairment.
Bibliographical noteFunding Information:
Supported by Grants from the National Institutes of Health (R01 EY002934 to GEL; R01 EY027857 to MK), by the Envision Fellowship from the Envision Research Institute (Y-ZX), by a Research to Prevent Blindness/Lions Clubs International Foundation low vision research award (to MK), by grants from the National Eye Institute (K23 EY018356 to AKB; R21 EY023720 and P30 NR008995 to AKB), and by the Foundation Fighting Blindness. The authors thank Cynthia Owsley for sharing data (supported by National Institute on Aging grant P50 AG11684) and for commenting on our manuscript.
- Contrast sensitivity
- Eye disease
- Visual acuity