Acute zonal occult outer retinopathy (AZOOR) is a rare syndrome characterized by sudden onset of photopsia, scotomas, and abnormal electrophysiological tests, predominantly affecting young women. Although its pathogenesis remains unknown, auto-reactivity to retinal components is thought to mediate tissue damage. A 42-year-old woman presented with symptoms and examination consistent with the diagnosis of AZOOR. She was treated with azathioprine for 5 years. In spite of the immunosuppressive treatment, clear progression in the visual field, autofluorescence, electrophysiological tests and optical coherence tomography was observed. Treatment with intravenous immunoglobulins (IVIg) and subcutaneous Abatacept was subsequently started with little efficacy. Hereby, we present a case of progressive AZOOR despite aggressive immunosuppression with 10-year follow up. Currently, there is no consensus regarding management of AZOOR, and the convenience of administering aggressive immunosuppression remains uncertain.