Like a painter with an increasingly limited palette, age-related macular degeneration (AMD) can dim the world of color for those affected. In this study, researchers examined the impact of AMD on two aspects of visual function: color vision and the pupil light reflex (PLR). By comparing patients in different stages of AMD to a control group, they found that individuals with early dry AMD experienced reduced color discrimination across all three color axes, indicating a widespread alteration in color vision. Additionally, the PLR, which involves the reaction of the pupils to light stimuli, was affected in both early dry AMD and neovascular AMD (NVAMD) patients. The melanopsin-driven response, responsible for regulating sleep-wake cycles, was reduced in both groups compared to the control group, suggesting disruptions in circadian rhythm associated with AMD. Rod-driven responses, related to low-light conditions, also exhibited differences between the NVAMD group and controls. These findings highlight how AMD can impact not only color perception but also the physiological response to light. This research underscores the importance of evaluating visual function beyond acuity measurements in individuals with AMD and may contribute to developing more sensitive tests for monitoring changes in this eye condition.

IntroductionAge-related macular degeneration (AMD) is the leading cause of irreversible central vision loss in developed countries and one of the leading causes of blindness. In this work, we evaluated color vision and the pupil light reflex (PLR) to assess visual function in patients with early and neovascular AMD (NVAMD) compared with the control group.MethodsWe recruited 34 early patients with dry AMD and classified them into two groups following AREDS: 13 patients with NVAMD and 24 healthy controls. Controls and patients with early dry AMD had visual acuity (VA) best or equal to 20/25 (0.098 logMAR). Color vision was assessed in controls and patients with early dry AMD using the Cambridge Color Test (CCT) 2.0 through the Trivector protocol. The PLR was evaluated using a Ganzfeld, controlled by the RETI–port system. The stimuli consisted of 1s blue (470 nm) and red (631 nm) light flashes presented alternately at 2-min intervals. To assess the cone contribution, we used a red flash at 2.4 log cd.m–2, with a blue background at 0.78 log cd.m–2. For rods, we used 470-nm flashes at –3 log cd.m–2, and for the melanopsin function of ipRGCs, we used 470 nm at 2.4 log cd.m–2.ResultsPatients with early dry AMD had reduced color discrimination in all three axes: protan (p = 0.0087), deutan (p = 0.0180), and tritan (p = 0.0095) when compared with the control group. The PLR has also been affected in patients with early dry AMD and patients with NVAMD. The amplitude for the melanopsin-driven response was smaller in patients with early dry AMD (p = 0.0485) and NVAMD (p = 0.0035) than in the control group. The melanopsin function was lower in patients with NVAMD (p = 0.0290) than the control group. For the rod-driven response, the latency was lower in the NVAMD group (p = 0.0041) than in the control group. No changes were found in cone-driven responses between the control and AMD groups.ConclusionPatients with early dry AMD present diffusely acquired color vision alteration detected by CCT. Rods and melanopsin contributions for PLR are affected in NVAMD. The CCT and the PLR may be considered sensitive tests to evaluate and monitor functional changes in patients with AMD.

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