Predominant loss of the photopic negative response in central retinal artery occlusion

Abstract

Purpose To determine how the photopic negative response (PhNR) is affected in central retinal artery occlusion (CRAO). Design Observational case series. Methods Seven patients with unilateral CRAO were included. Full-field scotopic and photopic electroretinograms (ERGs) including the PhNR were recorded. Each ERG amplitude in the affected eye was expressed as a percentage of amplitude of the corresponding wave in the unaffected eye. Results Mean of the PhNR amplitude was reduced to 12.3 ± 11.7% of that of unaffected eyes whereas the cone b-wave amplitude was attenuated to only 73.4 ± 30.4%. This reduction of the PhNR amplitude was more significant than that of other waves including the rod b-wave, maximum a-wave and b-wave, cone a-wave and b-wave, and 30 Hz flicker ERG ( P < .005). Conclusions The PhNR was severely affected in CRAO despite relative preservation of the cone b-wave, implicating massive loss of ganglion cells and their axons.