Intravitreal injection of ranibizumab with and without prior anterior chamber paracentesis in diabetic macular oedema using optical coherence tomography angiography

Background Intravitreal injections (IVI) of anti-VEGF agents are the gold standard for treatment of diabetic macular edema (DME), but they cause acute intraocular pressure (IOP) spikes that may affect retinal microvasculature. Anterior chamber paracentesis (ACP) can prevent these IOP elevations. Aim To assess the effects of transient changes in IOP on retinal microvasculature using optical coherence tomography angiography macular and peripapillary vessel density (VD), highlighting the role of ACP before IVI of Ranibizumab on retinal microvasculature in patients with DME. Settings and design A prospective comparative interventional study conducted in the Ophthalmology department of Ain Shams University Hospital between October 2022 and March 2024. Patients and methods This study included 102 eyes with nonischemic diffuse center-involving DME. Eyes were randomized into two groups: group A (51 eyes) received intravitreal ranibizumab without prior ACP, and Group B (51 eyes) received intravitreal ranibizumab with prior ACP. Optical coherence tomography angiography was performed to measure VD parameters in macular and peripapillary regions pre-operatively, immediately postoperatively, and on the first postoperative day. Results The mean change in IOP (ΔIOP) from baseline was +12.0±3.4 mmHg in group A (without ACP) and −5.2±1.8 mmHg in group B (with ACP), demonstrating a significant difference between the two groups. Immediate postoperative superficial and deep vessel densities were significantly reduced in group A compared with group B. Disc angiographic parameters showed pronounced transient decrease in group A but remained stable in group B. Although partial recovery occurred by the first day, VD parameters in group A remained below preoperative levels. Conclusion Prophylactic ACP effectively prevents acute IOP-related effects on retinal microvasculature during intravitreal ranibizumab injection. These findings support the routine use of ACP to enhance the safety profile of intravitreal therapy in DME management.