Abstract
Purpose :
Although several risk factors for developing NAION have been identified, many have not been studied as potential contributors to NAION in the fellow eye. The Ischemic Optic Neuropathy Decompression Trial (IONDT) found that diabetes and poor visual acuity (in the first affected eye) were associated with fellow eye NAION. We performed a retrospective chart review of all patients diagnosed with ischemic optic neuropathy over a 10 year period at a single eye center to identify other ocular and systemic risk factors associated with fellow eye NAION.
Methods :
ICD-9 (377.41) and -10 (H47.01) codes were used to identify all records of patient visits coded for “ischemic optic neuropathy” between 2007 and 2017. Patients were included if clinical data supported the diagnosis of NAION. Exclusion criteria were giant cell arteritis and fellow eye optic atrophy or bilateral NAION at time of diagnosis. The following data were collected: age, sex, and presence of systemic and ophthalmic comorbidities. Kaplan Meier analysis was used to calculate 5-year risk of fellow eye NAION. Cox proportional hazard regression was used to calculate hazard ratios for potential risk factors for fellow eye involvement.
Results :
119 patients met study criteria. Fellow eye NAION occurred in 29 (24%) patients. Five-year risk of fellow eye involvement was 27% (95% CI 19 to 38%). On univariate analysis, significant risk factors for fellow eye NAION included bilateral ODD (n=11, HR 2.8, 95% CI 1.12 to 6.90, p=0.02) and non-compliance with CPAP (HR 4.50, 95% CI 1.79 to 11.3, p=0.0058) in patients with moderate-to-severe obstructive sleep apnea (OSA). Of 35 patients recommended to use CPAP, 10 (29%) were noncompliant. Both risk factors (bilateral ODD and CPAP non-compliance) remained significant on multivariate analysis. Other systemic vascular risk factors and ocular comorbidities were not associated with fellow eye NAION.
Conclusions :
ODD and non-compliance with CPAP are associated with increased risk of NAION in the fellow eye. Possible explanations include structural (ODD) or metabolic (untreated OSA) compromise of optic nerve head vasculature. Compliance with CPAP in patients with unilateral NAION should be stressed to avoid potentially devastating bilateral optic neuropathy.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.