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

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.