Mapping of central visual function by microperimetry and autofluorescence in patients with Best's vitelliform dystrophy

Abstract

To evaluate retinal sensitivity and fixation patterns in patients with Best's dystrophy by microperimetry (MP) and to correlate the results with static perimetry and retinal morphology seen by autofluorescence (AF). Central 10 degrees visual fields in 11 patients with Best's dystrophy (VA: 0.5+/-0.38) were recorded by the Octopus M2 TOP program and by MP (MP1, Nidek Technologies). AF was recorded by HRA (Heidelberg Engineering). High correlation (R=0.75, -0.76, -0.48) was found between static perimetry (MS, MD and CLV indices) and MP. Based on MP and AF results, three groups of patients were formed. Patients in the first two groups fixated inside the central nonuniform hypo- and hyperfluorescent AF ring area, next to relative (Group 1) or absolute scotoma (Group 2). Inner parts of the retina close to the fovea were most affected, whereas regions closer to the periphery of the 10 degrees visual field showed near normal function. As the disease progressed, there was an evident shift of fixation to preferential retinal locus (PRL) in eight eyes with visual acuity 0.2 or less (Group 3). Fixation shift was superior in four eyes, temporal in two eyes, and nasal in two eyes. MP enabled a highly sensitive topographic monitoring of retinal function, showing central or pericentral fixation in the early stages, until loss of central function, in eyes with VA 0.2 or less, caused evident shift of fixation to PRL. PRL was never situated inside the central uniform hypofluorescent area, but corresponded with the hyperfluorescent ring seen with AF imaging.