Unilateral acute idiopathic maculopathy (UAIM) is an uncommon inflammatory disease of the retinal pigment epithelium (RPE) that affects young adults. The variability of clinical features of UAIM makes the diagnosis cumbersome. We report on a 25-year-old man with sudden loss of visual acuity (VA) and a central scotoma in his right eye. Fluorescein angiography localised the lesion in the RPE. Microperimetry revealed a central scotoma extending beyond the lesion margins with complete recovery of retinal sensitivity over weeks. Optical coherence tomography at presentation showed a thickened RPE. We are unaware of previous reports of UAIM studied by microperimetry and could find no reference to it in a computerised search using MEDLINE.