The Effect of Intravitreal Ranibizumab Injection on Retinal Nerve Fiber Layer Thickness and Optic Disc Parameters

Objectives: To evaluate the effects of intravitreal ranibizumab on retinal nerve fiber layer (RNFL) thickness and optic disc parameters in patients treated for exudative age-related macular degeneration (AMD), diabetic macular edema (DME), and retinal vein occlusion (RVO). Methods: This retrospective study analyzed the clinical records of 60 patients who received intravitreal ranibizumab injections for macular edema secondary to AMD, DME, or RVO between October 2014 and January 2016. All patients received intravitreal ranibizumab at a dose of 0.5 mg. Best-corrected visual acuity (BCVA) and intraocular pressure (IOP) were recorded at baseline and during follow-up. RNFL thickness and optic disc parameters were assessed using optical coherence tomography (OCT) and Heidelberg Retina Tomograph III (HRT-3). Measurements were obtained before treatment and at 1 week, 1 month, 3 months, and 6 months after injection. Comparisons were performed within and between disease groups. Results: Of the 60 patients, 31 (51.7%) had DME, 20 (33.3%) had AMD, and 9 (15.0%) had RVO. Best-corrected visual acuity improved significantly during the follow-up period. Mean RNFL thickness measured by OCT showed a significant reduction in the DME and RVO groups (p = 0.0001 and p = 0.043, respectively). In contrast, no significant changes in RNFL thickness were detected using HRT-3, and no consistent alterations in other optic disc parameters were observed. Changes in optic disc parameters varied among disease groups. Conclusions: Intravitreal ranibizumab treatment was associated with a reduction in mean RNFL thickness measured by OCT in patients with DME and RVO during a six-month follow-up period, whereas no corresponding RNFL thinning was detected using HRT-3 in any disease group. The observed optic disc parameter changes appeared to be disease specific. Given the absence of untreated control eyes and the exclusion of patients with glaucoma, these findings apply only to non-glaucomatous eyes and should not be extrapolated to patients with glaucoma. Further prospective studies with larger cohorts, appropriate control groups, and longer follow-up durations are warranted to clarify the long-term effects of anti-VEGF therapy on the optic nerve.