Clinical profile and perioperative risk factors for post-cataract surgery nonarteritic anterior ischemic optic neuropathy in an Indian population: An emulated target trial

PURPOSE: Cataract surgery is associated with a four times increased risk of nonarteritic anterior ischemic optic neuropathy (NAION). This paper presents the first report of patients from Indian ethnicity with post-cataract surgery NAION (psNAION) and aims to evaluate perioperative risk factors for prediction of psNAION. METHODS: A retrospective evaluation of patients who developed psNAION was done and clinical characteristics noted. An emulated target trial to evaluate the role of perioperative blood pressure and blood sugar, and postoperative intraocular pressure was conducted with controls matched for age, sex, systemic and ocular comorbidities with known risk of NAION, grade of cataract, type of surgery, type of anesthesia, and intraoperative complications. RESULTS: Nineteen patients (8 males, 11 females) aged 66.6 ± 7.7 years developed psNAION 80.8 ± 50.6 days after cataract surgery. Five (21.1%) patients had no known systemic risk factors for NAION. Three patients presented <7 days and 16 presented >6 weeks from surgery. None of the evaluated variables (perioperative blood pressure and blood sugar, and postoperative intraocular pressure) correlated significantly with increased risk of psNAION. CONCLUSION: Onset of psNAION is much later in Indian patients. All patients had classical features of NAION, and clinical evaluation was sufficient to establish diagnosis. One-fifth of patients had no known coexisting risk factors. Perioperative control of blood pressure or blood sugar, and postoperative intraocular pressure were not associated with increased risk.