Non-Arteritic Anterior Ischemic Optic Neuropathy Before and During the COVID-19 Pandemic: A Retrospective Comparative...

Non-arteritic anterior ischemic optic neuropathy (NAION) is an ischemic disorder of the optic nerve head often associated with systemic vascular risk factors. While COVID-19 is primarily a respiratory disease, it has been linked to vascular and thromboembolic complications. This study compared the incidence, clinical characteristics, and outcomes of NAION diagnosed before and during the COVID-19 pandemic.

A retrospective review was conducted of new NAION cases at a tertiary neuro-ophthalmology clinic diagnosed between May 2017-May 2019 (Pre-COVID) and March 2020-March 2022 (During-COVID). Data collected included demographics, vascular risk factors, clinical presentation, visual acuity, optical coherence tomography-derived retinal nerve fiber layer (RNFL) thickness, and visual field mean deviation (VF MD). Statistical analyses employed Chi-square, Fisher's exact test, t-test, and Mann-Whitney U-test.

Among 1,543 clinic patients, 46 were diagnosed with NAION (Pre-COVID: 27; During-COVID: 19). The relative frequency of NAION increased during the pandemic (3.7% vs 2.6%). Patients in the During-COVID group had significantly higher rates of hypertension (84.2% vs 40.7%, p=0.003), atherosclerotic cardiovascular disease (15.8% vs 0%, p=0.033), suspected sleep apnea (36.8% vs 0%, p=0.001), obesity (21.1% vs 0%, p=0.013), and smoking history (42.1% vs 3.7%, p=0.001). Subacute onset was more frequent during the pandemic (36.8% vs 0%, p=0.001), suggesting delayed presentation. At three months, visual acuity was worse in the During-COVID group (logMAR 1.34 vs 0.72, p=0.014). Baseline RNFL thickness and VF MD did not differ significantly. Only 31.6% of During-COVID cases had documented SARS-CoV-2 infection.

During the COVID-19 period, NAION was proportionally more frequent and associated with increased vascular comorbidities, delayed presentation, and worse visual outcomes. Both direct viral and indirect pandemic-related factors may contribute.