To identify characteristics that can distinguish AAION from NAAION in emergency practice.

This is a multicentre retrospective case-control study. Ninety-four patients with AAION were compared to ninety-four consecutive patients with NAAION. We compared the clinical, biological, and ophthalmological characteristics at baseline of patients with AAION and those with NAAION.

Patients with AAION were older and more likely to have arterial hypertension. Cephalic symptoms and acute-phase reactants were more frequent in AAION. Profound vision loss and bilateral involvement were more frequent in AAION at baseline. Central retinal and cilioretinal artery occlusions was only observed in AAION, and delayed choroidal perfusion was more frequently observed in AAION than in NAAION. Using logistic regression, an age >70 years (OR = 3.4, IC95% = 0.8–16.1, p = 0.105), absence of splinter haemorrhage (OR = 4.9, IC95% = 1.4–20.5, p = 0.019), delayed choroidal perfusion (OR = 7.2, IC95% = 2.0–28.0, p = 0.003), CRP > 7 mg/L (OR = 43.6, IC95% = 11.6–229.1, p < 0.001) and platelets >400 × G/L (OR = 27.5, IC95% = 4.6–270.9, p = 0.001) were independently associated with a diagnosis of AAION. An easy-to-use score based on these variables accurately distinguished AAION from NAAION with a sensitivity of 93.3% and specificity of 92.4%.

In patients presenting with AION, a set of ophthalmological and laboratory criteria can efficiently discriminate patients with AAION and NAAION and can identify which patients would benefit from high-dose glucocorticoids. External validation of our results is required.