Optic Disc Edema in Non-arteritic Anterior Ischemic Optic Neuropathy

We investigated the clinical characteristics, time to resolution and the factors that influence it, and evolutionary pattern of optic disc edema (ODE) in non-arteritic anterior ischemic optic neuropathy (NA-AION). Our study was conducted in 591 consecutive patients (749 eyes) with NA-AION who fulfilled our inclusion criteria. On their first visit to our clinic, all patients had a detailed ophthalmic and medical history, a comprehensive ophthalmic evaluation, and stereoscopic color fundus photography and fluorescein fundus angiography. On each follow-up visit, the same ophthalmic evaluation was performed, except for fluorescein fundus angiography. The effect of steroid therapy on ODE was evaluated in a "patient choice study" in 723 eyes, i.e., patients who voluntarily opted to have (343 eyes) or not have (380 eyes) this therapy. To identify the factors that influence time to ODE resolution, parametric regression models for interval-censored data were fitted by maximum likelihood estimation using an SAS procedure. Our results indicate that the overall median time (25-75th percentile) to spontaneous resolution of ODE from the onset of visual loss was 7.9 (5.8-11.4) weeks. The ODE resolution time was longer in diabetics than in non-diabetics (p = 0.003) in the single factor model. Multi-factor analysis showed that worse initial visual field defects (p < 0.0001) and worse visual acuity (p = 0.04) were associated with a faster resolution of ODE. Those treated with steroid therapy within 2 weeks after onset of NA-AION had significantly (p = 0.0006) faster ODE resolution than untreated cases. Severity of initial visual loss and systemic diseases were identical in steroid treated and untreated patients. A characteristic evolutionary pattern of ODE in NA-AION was observed. In conclusion, our study showed that in NA-AION the time course for resolution of ODE is shorter with greater severity of initial visual field and visual acuity loss, which may relate to the number of axons permanently damaged during the acute stage. Steroid therapy was associated with shorter time to resolution of ODE. Resolution of ODE goes through a characteristic evolutionary process.