Multiple Evanescent White Dot Syndrome Masquarading as Atypical Optic Neuritis

Abstract

Abstract Background We report a case of multiple evanescent white dot syndrome (MEWDS) masquerading as atypical optic neuritis in a young female patient. Case presentation: A 23-year-old female presented with ocular pain and visual field defect in her left eye for one week. Her best corrected visual acuity was 20/20 on her right eye and 20/30 on her left eye. Pupillary size was 3 mm for both eyes. Relative afferent pupillary defect was detected on the left eye. Color vision test was normal for both eyes. Visual field test revealed blind spot enlargement on the left eye. On fundus examination, disc swelling was found on the left eye. Other abnormalities were not found. The patient was suspected with atypical optic neuritis. Fluorescein angiography showed hyperfluorescent spots in the posterior pole and leakage of disc on the left eye. Orbital magnetic resonance imaging did not show any abnormal findings or enhancement. Multifocal electroretinogram (mfERG) showed reduced amplitude for the involved area. There were relatively hyper-autofluorescence lesions outside fovea and hypo-autofluorescent fovea in blue light fundus autofluorescence (BL-FAF) image. En face optical coherent tomography (OCT) revealed multiple hyporeflective dots at the ellipsoid zone (EZ). Swept-source-OCT (SS-OCT) showed irregular cells in the EZ with increased outer retinal thickness. On repeated fundus examination, multiple white dots were found vaguely. The patient was diagnosed with MEDWS and was able to recover in six weeks. Conclusions Patients with MEDWS who present with disc swelling, ocular pain, and RAPD might be misdiagnosed as optic neuritis. In atypical optic neuritis, en face OCT, BL-FAF and SS-OCT can aid in the differential diagnosis.