Preserved Contrast Sensitivity in Early and Intermediate Age-Related Macular Degeneration and Marked Loss in Late Stage: ALSTAR2

Purpose: To cross-sectionally compare parameters from the quick contrast sensitivity function (qCSF)-area under the log CSF (AULCSF) and sensitivity at each spatial frequency-in older eyes with normal macular health and early, intermediate, and late AMD. Our purpose was to determine whether qCSF could be a promising functional outcome measure in interventions designed to slow AMD progression from aging to late AMD. Methods: qCSF contrast sensitivity was measured at 1.0 to 18 cycles per degree (cyc/deg). Models evaluated the impact of diagnostic group on the AULCSF and individual spatial frequencies, adjusting for age and lens status. The AREDS nine-step classification system defined AMD presence and severity. Results: Eight hundred twenty-three eyes were studied: 383 normal macular health, 203 early AMD, 208 intermediate AMD, and 29 late AMD (23 geographic atrophy, six neovascular AMD). AULCSF decreased with increasing AMD severity; this was mostly attributable to the late AMD eyes having lower AULCSF than other groups. Late AMD eyes had significantly worse sensitivity at 1 and 1.5 cyc/deg compared to all other groups, with other groups having similar sensitivity. At frequencies near or just beyond the CSF peak (3-12 cyc/deg), late AMD eyes again had the worst sensitivity, with intermediate AMD eyes having slightly worse sensitivity than early AMD eyes. There were no group differences at 18 cyc/deg. Conclusions: The qCSF will be most useful in trials studying the transition from intermediate AMD to late-stage AMD, rather than in studying the transition from aging to early and intermediate AMD.