Risk Factors for Fellow Eye Involvement in Patients with Nonarteritic Anterior Ischemic Optic Neuropathy

Abstract

Introduction: The aim of the study was to investigate the possible risk factors for fellow eye involvement in patients with nonarteritic anterior ischemic optic neuropathy (NAION). Methods: A total of 113 patients with unilateral NAION attack were included and divided into two groups according to whether fellow eye involvement was present over a mean follow-up period of 2.70 years (P25–P75: 0.77–3.54 years). General characteristics (including age, sex, diabetes, hypertension, hyperlipidemia, and obstructive sleep apnea syndrome [OSAS]) and ocular characteristics (including initial best-corrected visual acuity, initial visual field damage of the first eye, and the presence/absence of a crowded disc) were analyzed and compared between the two groups. Cox regression was used to assess the risk factors for fellow eye involvement. Results: During the follow-up period, 40 patients developed fellow eye involvement. The initial best-corrected visual acuity (p = 0.048) and mean deviation of the visual field (VF) (p = 0.039) of the first eye in patients with fellow eye involvement were worse than those in patients without it. Diabetes (HR = 3.06, 95% CI: 1.50, 6.26, p = 0.002) and increased VF damage (moderate vs. mild, HR = 2.92, 95% CI: 1.03, 8.25, p = 0.043; severe vs. mild, HR = 5.01, 95% CI: 1.65, 15.20, p = 0.004) were associated with a significantly increased risk of fellow eye involvement. In 57 patients with apnea-hypopnea index (AHI) data for further study, an AHI score ≥23.2 was also found to be a risk factor (HR = 3.36, 95% CI: 1.17, 9.69, p = 0.025). Conclusion: Diabetes, severer initial VF damage, and more severe OSAS were risk factors for fellow eye involvement in NAION. For patients with these risk factors, more intensive follow-ups might be warranted.