Nonarteritic Anterior Ischemic Optic Neuropathy Is Associated With Proliferative Diabetic Retinopathy but Not Pan-Retinal Photocoagulation

Background: To evaluate whether proliferative diabetic retinopathy (PDR) is associated with an increased risk of nonarteritic anterior ischemic optic neuropathy (NAION) and whether pan-retinal photocoagulation (PRP) alters that risk. Methods: A retrospective cohort study was conducted using the TriNetX global health research network. Adults (18 years and older) with ≥3 years of follow-up and no prior NAION were included. In Analysis 1, patients with PDR were compared with those with diabetes mellitus without diabetic retinopathy. In Analysis 2, patients with PDR who underwent PRP were compared with those who did not. Propensity score matching was controlled for demographics and comorbidities. The primary outcome was incident NAION within 3 years. Results: After matching, 30,588 patients were included in each group for Analysis 1. At 3 years, NAION incidence was significantly higher in the PDR cohort than the DM without DR group (0.24% vs 0.09%; HR 2.81, 95% CI 1.80–4.40; P < 0.001). In Analysis 2, 8,126 patients were included in each group. No significant difference in NAION risk was observed between PRP and No PRP cohorts at any time point (3-year incidence: 0.34% vs 0.31%; HR 1.12, 95% CI 0.65–1.92; P = 0.680). Conclusions: PDR is associated with increased NAION risk, suggesting a role for local microvascular changes. PRP does not significantly alter NAION risk, supporting its safety in this context. Further studies with imaging data are warranted to clarify underlying mechanisms.