Improvement of Electroretinogram after Radial Optic Neurotomy for Central Retinal Vein Occlusion

Abstract

Abstract: : Purpose: Electroretinograms (ERG) are sensitive indicators of retinal ischemia in eyes with central retinal vein occlusion (CRVO). Recently, radial optic neurotomy (RON) has been introduced as a beneficial surgical procedure for CRVO. We report our initial experiences, and the ERG changes after RON for CRVO. Methods: Nine eyes of 9 patients with ischemic CRVO whose visual acuities were 20/400 or worse underwent pars plana vitrectomy and RON. Full–field ERGs to single bright–flash stimuli were recorded preoperatively and at 3 months postoperatively. The ratio of the affected eye/fellow eye for the a– and b–wave amplitudes was evaluated. Results: RON was performed in all cases without major complications. Postoperative fluoresccein angiograms revealed marked improvement of retinal circulation in all operated eyes. Preoperatively, the amplitudes of the a– and b–wave to the single flash stimuli were markedly reduced in all affected eyes. The ratios of the affected eye/fellow eye for the a– and b–wave amplitudes were 0.81±0.23 (mean±SD) and 0.63±0.17, respectively. The a– and b–wave amplitudes were significantly increased after RON, and the postoperative ratio of the a–wave was 0.89±0.31, and that of b–wave was 0.86±0.35. The mean implicit time of the a–wave was shortened from 24.4 to 21.9 ms, and that of the b–wave from 56.1 to 48.8 ms postoperatively. Conclusions: Significant improvements were observed in the full–field ERGs after RON in eyes with CRVO. The improvement of retinal function by this surgical procedure was most likely due to an improvement of retinal circulation.

Keywords: electrophysiology: clinical • vascular occlusion/vascular occlusive disease • vitreoretinal surgery