Multimodal imaging features of resolving multiple evanescent white dot syndrome.

Abstract

Multiple evanescent white dot syndrome (MEWDS) is as a self-limiting condition characterized by multiple small, ill-defined white dots at the level of the retinal pigment epithelium or outer retina with a distinct granular appearance in the fovea. The absence of the typical white dots may make recognition of MEWDS challenging. The authors present multimodal imaging features of resolving MEWDS with the absence of the white dots on fundus examination. A 22-year-old caucasian woman presented with a history of photopsia and sudden visual loss in the left eye (LE) for the past 3 weeks. Medical history was unremarkable. Best-corrected visual acuity (BCVA) was 20/20 with −1.75 sph in the right eye and 20/32 with −2.00 sph in the LE. Multimodal imaging of left eye at presentation is shown in Fig. 1. Fundus examination revealed foveal granularity. Optical coherence tomography (OCT) showed subfoveal interruption of the ellipsoid zone (EZ). Fundus autofluorescence (FAF) showed subtle hyperautofluorescent spots scattered at the posterior pole. Fluorescein angiography (FA) showed barely visible hyperfluorescent spots in the macula and beyond the temporal vascular arcades. Indocyanine green angiography showed barely visible hypocyanescent dots which matched the hyperfluorescent dots visible on FA. En face OCT scans at the level of the EZ showed small round hyporeflective lesions at the posterior pole. OCT scan passing through the dot located temporal to the fovea showed focal interruption of EZ [Fig. 2].Figure 1: Multimodal imaging of left eye at presentation. (a) Color fundus photograph shows foveal granularity. (b) Blue fundus autofluorescence shows tiny hyper-autofluorescent spots (yellow stars). (c) Fluorescein angiography shows subtle hyperfluorescent spots (white stars). (d) Indocyanine green angiography shows subtle hypocyanescent dots which match the dots shown by fluorescein angiography. (e) Near-infrared reflectance imaging shows foveal granularity (arrowhead) and hyporeflective dots (yellow stars) which match some of the dots visible on fundus autofluorescence. (f) Vertical optical coherence tomography scan shows subfoveal interruption of the ellipsoid zone (white arrow). (g and h) En face optical coherence tomography at the level of the ellipsoid zone shows small round hyporeflective lesions (white circles)Figure 2: Optical coherence tomography scan of resolving multiple evanescent white dot syndrome at presentation and 6 weeks after. (a) At presentation optical coherence tomography scan shows a focal interruption of the ellipsoid zone at the level of the dot located temporal to the fovea (white arrow). (b) Six weeks after presentation, the dot located temporal to the fovea has resolved and optical coherence tomography scan shows complete restoration of the ellipsoid zoneA diagnosis of MEWDS was made and observation was decided. Six weeks later, BCVA spontaneously improved to 20/20 in the LE. Transfoveal OCT scan [Fig. 3] showed complete recovery of the EZ in the LE. FAF and ellipsoid en face OCT showed resolution of the lesions noted at the time of presentation.Figure 3: Multimodal imaging of left eye, 6 weeks after presentation. (a) Fundus examination shows persistence of foveal granularity. (b) Blue fundus autofluorescence shows complete resolution of the hyperautofluorescent spots. (c) Near-infrared reflectance imaging shows resolving foveal granularity and resolution of the hyporeflective dots. (d) Vertical optical coherence tomography scan shows restoration of the subfoveal ellipsoid zone. (e and f) En face optical coherence tomography scans at the level of the ellipsoid zone (same slab as in Figure 1, after manual segmentation) shows resolution of the small hyporeflective lesionsMEWDS was first described by Jampol et al.[1] as a self-limiting condition characterized by multiple small, ill-defined white dots at the level of the retinal pigment epithelium or outer retina with a distinct granular appearance in the fovea. This condition typically occurs in young healthy women, and the lesions may be subtle and fade within the first few weeks of the disease. Since the first description, the use of multimodal imaging including high-resolution OCT has helped to clarify that the disease primarily involves the photoreceptors, especially the EZ.[23] Fundus autofluorescence and more recently en face OCT have provided further insights into the pathogenesis of this condition and have been proposed as noninvasive imaging techniques to monitor the clinical course.[45] In accordance with a previous study,[5] optical coherence tomography angiography of the retinal microvasculature and choriocapillaris was unremarkable in our case [Fig. 4]. This finding supports the hypothesis that choriocapillaris may not be involved in the pathogenesis of this condition which is primarily the result of inflammation at the photoreceptors.[5] We present a case of MEWDS with the absence of the typical white dots on fundus examination. Since the patient's symptoms had been lasting for 3 weeks, the white dots were most likely resolving at the time we observed the patient.Figure 4: Optical coherence tomography angiography of resolving multiple evanescent white dot syndrome at presentation and 6 weeks after. (a-d) At presentation, no obvious microvascular flow abnormalities at the level of the superficial capillary plexus (a), deep capillary plexus (b), choriocapillaris (c), and choroid (d) are visible on optical coherence tomography angiography. (e-h) Six weeks after presentation, no significant changes are visible on optical coherence tomography angiographyConclusion The present case outlines the key role of FAF, near-infrared reflectance imaging and en face OCT as noninvasive imaging techniques in detecting the resolving white dots and monitoring the clinical course of this condition. When multimodal imaging is not available, the presence of foveal granularity on fundus examination may help to recognize resolving MEWDS. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.