Comparison of Visual Outcomes of Nonarteritic Anterior Ischemic Optic Neuropathy in Patients with and without Diabetes Mellitus

Abstract

Purpose: Diabetic patients have a greater risk of nonarteritic anterior ischemic optic neuropathy (NAION) than nondiabetic patients. We compare visual outcomes, prevalence of bilateral/sequential ION, and predictors of visual outcomes in NAION between diabetic and nondiabetic patients.

Design: Case-control study.

Participants: All 231 patients with NAION seen by the Neuro-Ophthalmology Service, Wilmer Eye Institute, between 2002 and 2011 were screened for study inclusion.

Methods: Patients presenting within 4 weeks of symptom onset (30 with diabetes mellitus, 62 control patients) were included in baseline demographic assessments of vascular risk factors. Interval and final visual outcomes (logarithm of the minimum angle of resolution [logMAR] visual acuity [VA]) were evaluated in the 81 patients in this group with clinical follow-up for ≥3 months, and population average logistic regression models were used to determine risk factors for worse visual outcomes.

Main outcome measures: Visual acuity at last follow-up.

Results: The median follow-up duration was 38.7 weeks in diabetic patients and 52.9 weeks in nondiabetic patients. The majority (92.5%) of patients presented within 2 weeks of symptom onset. In nondiabetic patients, the most prevalent risk factor for NAION was hyperlipidemia (62.9%); for diabetic patients, NAION risk factors included hypertension (83.3%), hyperlipidemia (83.3%), and small cup-to-disc ratio (63.3%). Sequential NAION occurred in 36.8% of diabetic patients and 20.9% of nondiabetic patients. At last follow-up, 48% of diabetic and 62% of nondiabetic patients had VA better than 20/40. Similar proportions of diabetic and nondiabetic patients (8 [27%] diabetic and 14 [22.5%] nondiabetic patients) recorded a final follow-up vision of 1.0 logMAR or worse at a minimum of 3 months. Ischemic heart disease (odds ratio [OR], 7.21; P < 0.001) and greater age (OR, 1.05; P = 0.045) were associated with increased risk for final VA <20/200 in the multiple regression model (OR, 4.35; P = 0.011).

Conclusions: The VA at presentation and at final follow-up in diabetic patients with NAION were not significantly different from nondiabetic controls, although diabetic patients had a higher prevalence of cardiovascular risk factors. Ischemic heart disease and greater age, but not diabetes, independently correlated with worse VA outcome.