Subfoveal choroidal thickness in multiple evanescent white dot syndrome

Background: Multiple evanescent white dot syndrome (MEWDS) is an inflammation of the choriocapillaris, which typically presents with unilateral vision loss and is characterised by the presence of multiple yellow-white spots in the posterior pole to the midperipheral fundus. This study was conduced to evaluate subfoveal choroidal thickness between the acute and convalescent phases in two patients with MEWDS. Methods: Two young female Japanese patients underwent a comprehensive ophthalmic examination, including slitlamp biomicroscopy, funduscopy and both fluorescein and indocyanine green angiographies. The subfoveal choroidal and central retinal thicknesses were measured using Cirrus high-definition spectral-domain optical coherence tomography. Results: The two patients were diagnosed with unilateral MEWDS based on characteristic funduscopic and angiographic findings. The disrupted foveal inner segment-outer segment boundary line in the acute phase was restored in the convalescent phase in both patients. In the affected eye of Patient 1, the subfoveal choroidal thickness (337 mm) noted in the acute phase decreased to 249 mm at 133 days after the initial visit (convalescent phase). Similarly, the acute phase thickness (440 mm) in Patient 2 decreased to 358 mm at 133 days after the initial visit. The thickness in the asymptomatic opposite eye also decreased during the convalescent phase in both patients. In the acute phase, thickness in the affected eyes was greater than that in the opposite eyes in both patients. In contrast, central retinal thickness remained unchanged in both eyes during follow up in both patients. Conclusion: This is the first report to describe the relationship between subfoveal choroidal thickness and MEWDS. We found that the choroid was thicker in the acute phase than the convalescent phase in both the affected and opposite eyes of both patients, suggesting that an inflammatory reaction might occur in the choroidal stroma in addition to the choriocapillaris and might be bilateral rather than unilateral.