Abstract
Purpose:
To evaluate the effect of repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents on the thickness of the retinal nerve fiber layer (RNFL) in patients with neovascular age-related macular degeneration (AMD) utilizing spectral domain optical coherence tomography (SD-OCT) images.
Methods:
Eight eyes of 7 consecutive neovascular AMD patients (2 males and 5 females; mean age 70 ± 7 years), who were treated by a single physician (JIL) with a pro re nata (PRN) anti-VEGF (bevacizumab, ranibizumab, or aflibercept) regimen and underwent SD-OCT of the macula, were studied. Inclusion criteria were treatment with at least 10 anti-VEGF PRN injections and SD-OCT imaging before and after treatment with at least 12 months of therapy. Exclusion criteria were history of anti-VEGF treatment without pre-treatment SD-OCT imaging, glaucoma, or sustained intraocular pressure elevation post-treatment. RNFL was manually segmented on 19 SD-OCT B-scans through the macular area utilizing ImageJ software. Customized and automated image analysis software (Matlab) was used to calculate and map RNFL thickness from the segmented images. RNFL thickness was averaged over the entire macula as well as in the 9 Early Treatment Diabetic Retinopathy Study (ETDRS) subfields. To determine if RNFL thickness was reduced with treatment, measurements before and after treatment were compared with paired t-tests.
Results:
The mean number of injections was 17.9 ± 6.4 over a total treatment interval of 36.2 ± 11.4 months. Four patients received a combination of ranibizumab and aflibercept, 1 patient a combination of bevacizumab and ranibizumab, 2 patients ranibizumab only and 1 patient aflibercept only. The average time of follow-up was 38.5 ± 13.1 months. The mean difference in overall macular RNFL thickness (after - before treatment) was -0.78 ± 3.66 microns (p=0.28). There were no statistically significant differences in RNFL thickness in any of the 9 ETDRS subfields (p>0.07). The parafoveal inferior macular sector was the only subfield to show a trend towards thinning, with a mean change of -1.90 ± 3.16 microns (p=0.07).
Conclusions:
Patients who received multiple intravitreal anti-VEGF injections for neovascular AMD did not show evidence of significant reduction in macular RNFL thickness, but did show a trend towards thinning in the parafoveal inferior region.
Keywords: 412 age-related macular degeneration •
748 vascular endothelial growth factor •
610 nerve fiber layer