Normal to supernormal 30-Hz flicker ERGs predict visual function and prognosis in central retinal artery occlusion

Purpose To determine whether normal to supernormal 30-Hz flicker ERGs are associated with visual function and prognosis in patients with central retinal artery occlusion (CRAO). Methods A total of 133 patients diagnosed with unilateral acute non-arteritic CRAO by examination with electroretinography (ERG) were examined. Thirty-hertz flicker ERG amplitudes were analyzed according to the severity of CRAO, and their correlation with visual function and prognosis was assessed. All patients were categorized into one of three groups according to the flicker ERG amplitude ratios between affected and fellow eyes: >= 110%, supernormal; 90-110%, normal; and < 90%, subnormal. Results Thirty-hertz flicker ERG parameters differed significantly according to the severity of retinal ischemia, i.e., between incomplete versus complete CRAO: mean amplitude (55.89 +/- 24.38 > 45.41 +/- 23.47 mu V, P = 0.029), amplitude ratio (76.1 +/- 23.1% > 58.7 +/- 25.7%, P < 0.001), and proportion of normal to supernormal flicker ERGs (30.5% > 12.4%, P < .001). One-month and final follow-up visual function and prognosis were better in the normal to supernormal flicker ERGs: 1 month BCVA (1.55 +/- 0.65 > 2.05 +/- 0.61 logMAR, P < .001), final BCVA (1.32 +/- 0.79 > 1.97 +/- 0.68 logMAR, P < .001), 1-month VA improvement (- 0.50 +/- 0.47 > - 0.10 +/- 0.29 logMAR, P < .001), and final VA improvement (- 0.74 +/- 0.61 > - 0.18 +/- 0.37 logMAR, P < .001). Conclusions Normal to supernormal 30-Hz flicker ERG changes in eyes with CRAO are associated with the milder severity of retinal ischemia and showed better visual function and outcome than the subnormal ERG group.