Electrophysiological and structural assessment of the central retina following intravitreal injection of bevacizumab for treatment of macular edema

Purpose To evaluate with electrophysiological responses and Optical Coherence Tomography (OCT), the short term functional and structural effects at the macula following intravitreal injection of bevacizumab for macular edema. Methods Prospective, non-randomized, interventional case study. In total, 17 eyes of 17 patients with macular edema due to vein occlusions and diabetic retinopathy received intravitreal bevacizumab. All Patients underwent complete ophthalmic examination including Snellen visual acuity testing, Multifocal Electroretinography (mfERG) and Full Field Electroretinography (FERG), OCT scanning at baseline at 1 week and 2 months after intravitreal bevacizumab. Results FERG did not show any change in waveform parameters following intravitreal injection of bevacizumab. Average mfERG macular responses within central 20° showed increased P₁ amplitude (P < 0.05) at 2 months after treatment as compared to the baseline recordings in all subjects. No changes were seen in the implicit time. There was 22% improvement in central retinal thickness (CRT) at 2 months compared to the baseline (P < 001). Conclusion Intravitreal injection bevacizumab resulted in reduction in the central retinal thickness and mild to moderate improvement in the mfERG amplitudes in this short-term study. The visual acuity changes did not directly correlate with the reduced central retinal thickness or improvement in mfERG. The short-term results showed no serious ocular adverse effects. Therefore on short-term follow up the off label drug showed improvement of macular edema secondary to vein occlusion and diabetic retinopathy with no demonstrable toxic effects.