Abstract
Purpose: :
ascular endothelial growth (VEGF) is a neurotrophic factor that plays an important role in maintaining the neural cells in the retina. Repeated intravitreal injections of anti-VEGF monoclonal antibody have been reported to cause degeneration of the retinal ganglion cells (RGC) in rats (Nishijima et al., AJP, 2007). To evaluate the safety of intravitreal ranibizumab (IVR) in patients, we examined the RGC function using the photopic negative response (PhNR) of the electroretinogram (ERG) in patients with age-related macular degeneration (AMD) treated with IVR.
Methods: :
We studied 30 eyes of 30 patients with AMD whose age ranged from 50 to 84 years with a mean of 71 years. IVR was repeated 3 times every 4 weeks. ERG recordings were made before the treatment (baseline) and at 2 weeks after the last injection. The full-field cone ERGs were elicited by red stimuli on a blue background. The focal macular ERGs were elicited by a 15° white stimulus spot centered on the macular region. We measured the amplitudes of the a- and b-waves and the PhNR of the full-field cone and focal macular ERGs.
Results: :
The visual acuity was significantly better than the baseline acuity after the IVR, and the macular thickness was significantly reduced (P<0.01). The amplitudes of each wave of the full-field cone ERGs at the baseline were not significantly changed after the IVR. However, the amplitudes of each wave of the focal macular ERGs were increased after the IVR, but the increase was significant for only the b-wave and the PhNR amplitudes (P<0.001 for the b-wave; P<0.05 for the PhNR). The ratio of the focal PhNR/b-wave amplitude was not significantly different after the IVR.
Conclusions: :
These results indicate that the RGC function of the peripheral retina was not altered by repeated IVR. Because the amplitudes of the focal macular ERGs including the PhNR improved after repeated IVR accompanied by a recovery of the visual acuity and macular structure, we conclude that IVR does not have adverse effects on the RGC function of the macula.
Keywords: retina: proximal (bipolar, amacrine, and ganglion cells) • electroretinography: clinical • vascular endothelial growth factor