Abstract
Purpose :
It is not known what determines the location of the preferred retinal locus (PRL) in patients with macular degeneration. In this study, we tested the hypothesis that binocularity requirements for correspondence play a role in establishing the PRL.
Methods :
PRL locations of 101 patients (79±10 years old) with macular degeneration were recorded for both eyes (N=202 eyes) with the MP1 microperimeter, during short fixation tests. The better eye (BE) and the worse eye (WE) were identified from clinical charts. For each eye, the outcome measures were PRL distance from former fovea, polar angle, scotoma size, and fixation stability. Corresponding PRLs were those with the same polar angle and distance from former fovea in the BE and the WE.
Results :
Two groups were identified based on the status of the BE: 1) functioning central retina (N=55) and 2) central scotoma (N=46). For group 1, the PRL in the BE was in the foveal proximity (within 1.1±1deg) and that in the WE was: A) on functioning, corresponding location (N=13), B) on functioning, non-corresponding location (N=16), and C) on corresponding, non-functioning location (N=26). No PRL was located further away in eccentricity in the BE to allow for a PRL on functioning and corresponding retinal location in the WE. The BE’s outcome measures were equal to those of the WE in subgroup A, different in subgroup B, and different except for polar angle in subgroup C (p < .05). For group 2, the PRL in the BE was located eccentrically (6.9±3.4 deg from former fovea) and that in the WE was: A) on functioning, corresponding location in patients with equal scotomas in both eyes (N=15), and B) closer to a location corresponding to the PRL of the BE rather than to the former fovea in patients with unequal scotomas (N=19); C) in those with extensive scotomas in both eyes (size >20deg), the PRLs were generally not in correspondence and at extreme eccentricity suggesting limited functionality (N=12). The BE’s outcome measures were equal to those of the WE in subgroup A, different except for polar angle in subgroup B, and different except for the fixation stability in subgroup C (p < .05).
Conclusions :
In patients with functioning central retina in the BE, the PRL develops in the foveal proximity in this eye and likely drives binocular control. In those with central scotoma in the BE, the PRLs develop to maximize the binocular peripheral inputs from both eyes rather than to be at the closest location from the former fovea.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.