PATTERN‐REVERSAL ELECTRORETINOGRAMS IN SQUINT AMBLYOPIA, ARTIFICIAL ANISOMETROPIA AND SIMULATED ECCENTRIC FIXATION

Abstract

Pattern-reversal electroretinograms [ERG] were recorded in 10 normals and 10 adult patients with squint amblyopia (visual acuity .ltoreq. 0.3). The effects of artificial anisometropia and simulated eccentric fixation were tested in normals. The pattern-reversal ERG amplitude was reduced linearly with increased defocusing (0 to +3 D). A significant amplitude reduction was observed when defocusing amounted to + 1 D. The amplitudes were not reduced below the range of normal variability at 4.degree. of simulated eccentric fixation. In the amblyopic patients, refractive errors were corrected. None had eccentric fixation of more than 4.degree.. The pattern-reversal ERG were lower in all amblyopic eyes compared with the opposite normal eyes. The difference in amplitude means was statistically significant. Apparently, retinal function is impaired in human squint amblyopia.