Restored photoreceptor outer segment damage in multiple evanescent white dot syndrome

Abstract

Purpose: To report retinal tomography and function in the course of multiple evanescent white dot syndrome (MEWDS).

Design: Prospective case series.

Participants: Seven patients with unilateral MEWDS.

Methods: We performed optical coherence tomography (OCT), multifocal electroretinography (mfERG), full-field electroretinography (ffERG), fluorescein and indocyanine green angiography, and visual field examinations in 7 patients with active to resolved MEWDS.

Main outcome measures: OCT imaging of the posterior fundus with a 6 x 6-mm square, best-corrected visual acuity (BCVA), fundus characteristics, visual field measurements, mfERG, and ffERG responses.

Results: All patients reported unilateral blurred vision and spotty visual field defects. The fundi had yellow or white dots of various sizes and extent in the affected eyes. The visual fields had enlarged blind spots in all affected eyes and scotomas in 3 of the 7 eyes. In 5 of the all fellow eyes, 4 fellow eyes had an enlarged blind spot, peripheral visual field defects, or both; 1 eye had only a peripheral field defect. OCT showed a disrupted or irregular photoreceptor inner/outer segment (IS/OS) junction line of varied extent in 7 affected eyes and 1 fellow eye. During 1.5 weeks to 6 months follow-up (mean, 3.4 months), the BCVA returned to 1.2 along with resolution of the white dots in all eyes. The IS/OS line was restored in 7 eyes, but 1 eye had focal disruption. The visual fields returned to normal in 5 affected eyes; however, an enlarged blind spot remained in 2 affected eyes and a peripheral defect remained in 2 fellow eyes. On ffERG and mfERG, the decreased responses recovered markedly in the 7 affected eyes.

Conclusions: The lesions responsible for MEWDS appear to disrupt the photoreceptor outer segments; morphologic and functional recovery can occur. Although the symptoms and fundus lesions were visible unilaterally, the photoreceptor dysfunction was bilateral in most cases.