OBJECTIVE - To determine whether prolonged vascular endothelial growth factor inhibition is toxic to the retina by using pattern electroretinographic imaging in participants with neovascular age-related macular degeneration (AMD).
METHODS - We performed a prospective, single-arm clinical trial of 17 eyes in 17 treatment-naive participants with subfoveal choroidal neovascularization from AMD. On-label intravitreous ranibizumab was injected monthly for 6 months. Then pattern electroretinographic imaging was performed before and at 1 month, 3 months, and 6 months after first treatment, and results were interpreted by a trained reader masked to the clinical data. The primary outcome measure was the change in pattern electroretinographic imaging (positive wave peaking at 50 milliseconds [P50] and negative wave peaking at 95 milliseconds [N95] values) from baseline at 6 months. The secondary outcome measure was the change in visual acuity at 6 months.
RESULTS - The mean participant age was 79.6 years (range, 69.5-90.4 years). At baseline, mean (SD) P50 and N95 amplitudes were 1.3 (0.69) μV and 1.5 (0.71) μV, respectively. By 6 months, no decrease in P50 or N95 amplitudes from baseline was observed (1.4 [0.47] μV, P = .46; and 1.8 [0.96] μV, P = .14, respectively). Mean visual acuity before treatment was 20/85 with improvement to a mean of 20/55 (P = .004) at 6 months.
CONCLUSIONS - This study found no decrease in P50 and N95 amplitudes in participants treated with ranibizumab for neovascular AMD. These findings indicate that vascular endothelial growth factor inhibition with monthly injections of ranibizumab for 6 months likely does not lead to retinal damage. Trial Registration clinicaltrials.gov Identifier: NCT00500344.