Investigating ocular ischemic events following pars plana vitrectomy

Objective To assess the incidence of post–vitrectomy ocular ischemic events, including retinal artery occlusion (RAO), retinal vein occlusion (RVO), and non-arteritic ischemic optic neuropathy (NAION). Methods This retrospective cohort study examined 120,350 patients who underwent vitrectomy. Using a multicenter healthcare database, patients with a CPT code for any vitrectomy procedure were assessed for subsequent ocular ischemic events. A follow-up analysis of 510,915 patients was performed to determine the risk attributable to vitrectomy versus clinical characteristics. Exclusion criteria included history of prior ocular ischemic events and less than 6 months of follow up. Results The first post-operative month had a significantly higher risk of vascular occlusions compared to the 6–12-month period, with incidence rate ratios (IRRs) of 9.69 (95% CI: 6.9–13.7) for RAO, 11.43 (95% CI: 9.3–14.1) for RVO, and 8.75 (95% CI: 5.2–14.7) for NAION. The IRR for overall ischemic events was also increased during the first month following vitrectomy at 10.7 (95% CI: 9.0–12.7) and remained elevated up to 6 months later with an IRR of 1.49 (95% CI: 1.2–1.8) for the 3–6-month period compared to 6–12-months postoperatively. A separate multivariate analysis revealed that the risk of overall ischemic events was most correlated to vitrectomy (hazard ratio [HR] 3.32, 95% CI: 3.10–3.57) over multiple variables including cataract surgery (HR 1.49, 95% CI: 1.42–1.56) and nicotine use (HR 1.15, 95% CI: 1.08–1.22). Conclusions Vitrectomy is correlated with significantly increased risk of ocular ischemic events, particularly within the first month following surgery. This risk gradually declines but remains elevated up to 6 months postoperatively.