To present a case of acute zonal occult outer retinopathy (AZOOR) with acute idiopathic blind spot enlargement (AIBSE) investigated using indocyanine green angiography (ICGA), multifocal electroretinography (multifocal ERG) and spectral domain-OCT (SD-OCT).

A healthy 31-year-old female with photopsia and a five-day visual field defect in her left eye showed no abnormal findings in ocular examinations such as slit lamp and fundus examination, fluorescein angiography (FAG), or full field ERG as well as in the systemic neurologic examination. In the late phase of ICGA, there were multiple hypofluorescent spots around the optic disc and scattered through the posterior pole. The patient showed an amplitude decrease of multifocal ERG and the destruction of the boundary between the inner and outer segments of the photoreceptors in the SD-OCT examined in the retinal area corresponding to the visual field defect. The patient was diagnosed with AZOOR and was followed-up without treatment. After three months, no abnormal SD-OCT or visual field test findings were observed and no symptoms remained; however, a slightly depressed response on multifocal ERG was present.

ICGA, multifocal ERG and SD-OCT could be useful methods to detect AZOOR with EBS.