Effects of Intra-Vitreal Injection of Ranibizumab on Retinal Micro-Circulation in Patients with Retinal Vein Occlusion by Optical Coherence Tomography Angiography

Introduction: Retinal Vein Occlusion (RVO) is a frequent retinal vascular condition that causes much vision loss globally. It is the second leading cause of retinal vascular disease-related blindness after diabetic retinopathy. Since 1855, RVO has been identified, although its cause and treatment are unknown. Aim: to assess the central macular thickness (CMT), superficial foveal avascular zone (sFAZ), peri-foveal inter-capillary area & capillary drop-out areas in patients with retinal vein occlusion (RVO) before and after intra-vitreal injection (IVI) of Ranibizumab using Optical Coherence Tomography Angiography (OCT-A). Methods: The study included 14 eyes of 7 patients of both genders and any age with RVO either central or branch. Patients with old RVO, having previous IVI, media opacity or retinal pathology, underwent previous ocular surgeries or having poor compliance were excluded from the study. Complete medical history and ophthalmological examination was done, followed by 9x9mm OCT-A scans for superficial and deep capillary plexus. Patients underwent 3 monthly IVI of Ranibizumab. CMT, sFAZ, peri-foveal inter-capillary area & capillary drop-out parameters were assessed before and after each IVI. Results: CMT significantly (p < 0.001) decreased in patients with RVO after the three IVI of Ranibizumab. The micro-vascular ischemic changes happened in sFAZ, peri- foveal inter-capillary area & capillary drop-out areas were not improved after three IVI of Ranibizumab intra-vitreal injection, (p > 0.05). Conclusion: Ranibizumab is effective in treating macular edema associated with RVO. However, it has no effect on improving ischemic changes. OCT-A has a promising role in constructing a better understanding about the changes occuring in retinal micro-circulation in patients with RVO.