Electrophysiological evaluation of retinal photoreceptor function after repeated bevacizumab injections

Abstract

Bevacizumab (Avastin, Genentech) was one of the first anti-VEGF substances used to treat macular edema or choroidal neovascularization in patients with vascular ocular pathologies. However, only few studies evaluate the safety of intravitreal bevacizumab injections in regard to retinal photoreceptor function. We evaluated retinal function after repeated (2-3) monthly injections of bevacizumab in a prospective case series of 10 patients with various retinal diseases. Study endpoints were visual acuity (VA) using ETDRS charts and 3 full-field electroretinography sessions with a flash intensity range of 0.0005-2 cds/m(2). V-log-I b-wave amplitudes were fitted by a Naka-Rushton model. No significant changes in scotopic or photopic ERG measures were observed between baseline ERG and last follow-up ERG. Individual patients showed transient alterations of ERG measures on the first follow-up visit. Mean visual acuity was stable over the time course of the study (logMAR = 0.42 at baseline and logMAR = 0.48 at last follow-up). In conclusion, three monthly repeated injections of bevacizumab do not affect mid-term electrophysiological retinal function. Transient alterations in ERG readings of individual patients 1 week after intravitreal bevacizumab injection may be attributed to short-term disruption of the retinal equilibrium through the trauma of injection. Evaluation of patients receiving more than three injections of anti-VEGF substances should be the focus of future studies.