Serial Changes in Multimodal Imaging and Electroretinographic Findings in Acute Unilateral Outer Retinopathy Presenting With Blind Spot Enlargement

Acute blind spot enlargement can arise from either optic nerve or outer retinal disease.We report an acute outer retinopathy of the left eye in a 60-year-old man with bilateral high myopia.He was referred after three weeks of photopsia and blurred vision in the left eye.Best-corrected visual acuity was -0.08 logMAR in the right eye and 0.15 logMAR in the left eye (0.05 logMAR before onset), and axial lengths were 29.59 mm and 30.30mm, respectively, with a relative afferent pupillary defect in the left eye.There was no anterior chamber or vitreous inflammation, and no white dots or foveal granularity.Widefield fundus autofluorescence showed sharply demarcated peripapillary hyperautofluorescence and patchy midperipheral hyperautofluorescence in the left eye alone, whereas fluorescein and indocyanine green angiography showed no significant findings.Optical coherence tomography showed attenuation of the ellipsoid zone extending from nasal to the fovea toward the disc, and Humphrey 30-2 perimetry showed blind spot enlargement.Multifocal electroretinography showed reduced amplitudes in the left eye corresponding to the outer retinal and field abnormalities, while mean full-field amplitudes were within reference limits in both eyes.By about 20 weeks, the symptoms had resolved, left eye acuity had returned to 0.05 logMAR, and the outer retinal change, the multifocal amplitudes, and the field defect had all improved.The phenotype most closely resembled acute idiopathic blind spot enlargement, but findings overlapping with multiple evanescent white dot syndrome precluded a single diagnosis.Where the two overlap, serial multimodal imaging and electroretinography were useful in characterizing the process.