Abstract
Purpose: :
To determine how the retinal ganglion cell complex (GCC), composed of the inner retinal layers, is affected by pan-VEGF inhibition in patients undergoing treatment for exudative age-related macular degeneration (AMD).
Methods: :
13 eyes from 11 patients diagnosed with AMD and choroidal neovascularization (CNV) from 2007-2009, with visual acuities between 20/25 and 20/400, were enrolled, along with 4 control eyes (untreated contralateral eyes with dry AMD); none of the patients had glaucoma. All patients with CNV were treated with between 2 and 13 intravitreal injections of either ranibizumab or bevacizumab.Patients were imaged with Fourier-domain (FD) OCT both before receiving treatment and on the most recent follow-up. GCC thickness was measured in 8 sectors surrounding the fovea and extending out to 5 mm; the central 2 mm fovea was not analyzed because there are no ganglion cells in the foveola.
Results: :
There was an average decrease of 17.2 microns in pre-treatment vs. post-treatment GCC thickness, averaged across all sectors. There was a slight increase in GCC thickness of 2.2 microns on average for the control group. Follow-up averaged 8.4 months in the treated group and 6.5 months in the control group. The treated group received on average 5.8 injections over the course of the follow-up. There was a significant correlation between the number of injections and the amount of GCC thinning (r=0.50; p<0.05). We also compared the GCC thickness both pre-and post treatment against the FD-OCT normative database. In the treatment group there were 25 sectors (24.0%) that were below normal limits (p <0.05) before treatment, and 61 sectors (59.0%) below normal limits (p<0.05) after treatment. In the control group, there were 5 sectors (15.6%) below normal (p<0.05) on the first visit, and 3 sectors (9.4%) below normal (p<0.05) on the last visit.
Conclusions: :
The present study demonstrates that pan-VEGF AMD treatment may lead to GCC thinning. These results are consistent with previous animal studies demonstrating possible VEGF dependence of the GCC. The effect on visual function is unknown. Limitations of this study include a small sample size, and limited follow-up in some cases. Additional studies with larger sample sizes and longer follow-up are necessary to validate these findings.
Keywords: age-related macular degeneration • retina: proximal (bipolar, amacrine, and ganglion cells) • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)