Binocularity Principles of PRL Development in Patients With Macular Disease.

PURPOSE

We tested the hypothesis that binocularity requirements for correspondence play a role in establishing the preferred retinal locus (PRL) in macular degeneration.

METHODS

Monocular PRL locations in 202 eyes of 101 patients with macular degeneration (79 ± 10 years) were recorded with the MP1 microperimeter. Corresponding PRLs were those with similar polar angle and distance from former fovea in the better eye (BE) and the worse eye (WE).

RESULTS

On average, the PRL in the BE was in the foveal proximity at 1.1 ± 0.99 degrees for 55 patients (foveal-driven PRL) and eccentrically at 6.9 ± 3.4 degrees for 46 patients with central lesions involving the fovea (peripheral-driven PRL). For the foveal-driven PRL group, the PRL in the BE was not affected by the status of the WE. In 100% of cases, the monocular PRL in the WE was in a corresponding location either on functioning retina or onto the lesion, or would fall onto the lesion during binocular viewing. For the peripheral-driven PRL group, the PRL location depended on the lesion size in both eyes to maximize correspondence and/or the function of peripheral vision during binocular viewing. In this group, PRL correspondence status was different for those with equal, unequal, or extensive lesions in both eyes.

CONCLUSIONS

Binocularity requirements for correspondence play an important role in determining the PRL location. We formulated two principles based on whether the BE has foveal sparing (foveal-driven PRL) or central lesions affecting the fovea (peripheral-driven PRL). The PRL should be evaluated in the framework of binocular viewing.