Early multifocal electroretinogram findings during intravitreal ranibizumab treatment for neovascular age-related macular degeneration.

Purpose: To evaluate changes in the multifocal electroretinogram (mfERG) in patients with neovascular age-related macular degeneration (nAMD) undergoing ranibizumab treatment.

Methods: This was an observational, longitudinal, prospective study. Treatment-naive patients with nAMD who met the inclusion and exclusion criteria underwent a course of monthly injections of ranibizumab over 3 months. At baseline and month 3, each subject was evaluated with best corrected visual acuity (BCVA), contrast sensitivity (CS), fluorescein and indocyanine green angiography, optical coherence tomography (OCT), and mfERG. Additional mfERGs were performed at weeks 1 and 4 and BCVA and OCT at weeks 4 and 8.

Results: Eighteen patients were enrolled. Between baseline and week 12, median BCVA improved from 59 to 69 ETDRS letters (P = 0.001), median CS improved from 29 to 30 letters (P = 0.05), mean OCT central foveal subfield thickness (CFT) decreased from 294 to 199 μm (P = 0.005), mean P1 amplitude density of the mfERG central zone increased from 35.85 to 51.55 nV/deg(2) (P = 0.009). The mfERG response correlated positively with BCVA (F = 22; P < 0.0001) and negatively with CFT (F = 12.73; P = 0.00078).

Conclusions: Intravitreal ranibizumab therapy appears to induce an increase in mfERGs centrally in patients with nAMD at least in the short term. Longer term studies to investigate the prognostic value of mfERG responses to predict changes in visual acuity in nAMD and other diseases are warranted. (ClinicalTrials.gov number, NCT01023971.).