Mesopic visual function as a prognostic indicator of early age‐related maculopathy

Abstract

Abstract Purpose Rod photoreceptors, which mediate night vision, are vulnerable early in age‐related maculopathy (ARM) pathogenesis. This study was performed to analyze mesopic visual function of early ARM subjects. Methods The samples were 40 early ARM eyes of adults (65 ± 7 years), and 34 age‐matched healthy control eyes (67 ± 6 years). The selected criteria in both samples were: Best‐corrected VA of at least 0.9 decimal. Under photopic (80 cd/m2) and mesopic (0.1 to 0.2 cd/m2) luminance conditions and with the best‐optical correction, the logMAR VA was measured using high‐contrast (HC‐96%) and low‐contrast (LC‐10%) logMAR Bailey‐Lovie letter charts, and the mesopic contrast sensitivity (CS) was assessed with Pelli‐Robson Test Results Photopic high and low‐contrast VA showed no statistically differences between the two groups. Under mesopic conditions, the HC logMAR VA was 0.54 ± 0.13 in ARM group and 0.46 ± 0.10 in Control group. The ARM LC logMAR VA was 0.72 ± 0.11 and the Control LC logMAR VA was 0.99 ± 0.13. Differences in mesopic high and low contrast logMAR VA between the Control and ARM group were statistically significant; the Control group showing best logMAR VA at high and low contrast (p< 0.00). The mesopic ARM logCS was 0.99 ± 0.21 and the mesopic Control logCS was 1.19 ± 0.14. In ARM group, the mean mesopic log CS was 0.2 ± 0.08 log units lower (p< 0.00) than in the Control group. Conclusion The results indicated that assessment of the mesopic high and low contrast logMAR VA and log CS might potentially predict the mesopic visual function and the first night‐vision problems of the early ARM disease process