Purpose: To investigate long-term effect (96 months) of intravitreal ranibizumab administered for exudative age-related macular degeneration (AMD) on retinal nerve fiber layer (RNFL) thickness when used following a pro re nata regimen.
Methods: In this prospective study, 20 eyes of 20 patients diagnosed with exudative AMD were included. Contralateral non-exudative AMD eyes of nine of these patients were included as controls. Data on intraocular pressure (IOP) and number of injections were recorded. Spectralis optic coherence tomography (OCT) of the circumpapillary RNFL was performed under dilation when diagnosis was made and before the three loading injections. "Follow-up" software was selected to accurately compare baseline with subsequent images through the 8 years of the study.
Results: Baseline IOP was 14.1 mmHg both in study (standard deviation, SD: 0.8) and control eyes (SD: 0.9) and remained unchanged during the study. Mean number of injections was 21 (SD: 2.8) at the end of the study. Mean average thickness of RNFL in the study eye group at the end of the study was 96.5 μm (SD: 2.1). Mean loss for the study period was 5.3 μm (SD: 0.7; p < 0.0001). Corresponding RNFL values for controls were 92.9 (SD: 3.2) and 5.8 μm (SD: 1.2; p < 0.001). Superior temporal sector had the greatest loss in both groups, followed by inferior and nasal sectors. No statistically significant differences were found when comparing losses in injected eyes versus control eyes.
Conclusions: RNFL thickness decreased both equally in injected eyes and control eyes. Thus, no long-term effects of intravitreal ranibizumab were observed on the retinal nerve fiber layer thickness.
Keywords: AMD; Nerve fiber layer; OCT; Ranibizumab; anti-VEGF.