Small studies have highlighted the value of cerebral MRI (Magnetic Resonance Imaging) in CRAO with almost 25% of ischemic strokes found on diffusion sequences and the demonstration of a correlation between anomalies in diffusion sequence and the probability of a pathology with a high risk of recurrence (carotid stenosis or emboligenic cardiopathy). But there are usually few radiological signs that allow a direct positive diagnosis of CRAO, an etiologic diagnosis or a prognosis. This descriptive study will focus on CRAO at the diagnostic and post-treatment phases in the short and medium term, in order to (i) identify imaging etiologic signs of CRAO with specific sequences from a 3 Tesla MRI, (ii) identify positive diagnostic signs of CRAO with the same specific sequences, (iii) correlate these signs with the visual prognosis one month after the CRAO.