Multiple Evanescent White-dot Syndrome (MEWDS) is an acute multifocal, usually unilateral, retinopathy affecting young adults.
Multiple white dots are seen at the level of the deep retina or RPE. The white dots are mostly concentrated in the paramacular area, usually sparing the fovea itself and are less prominent and numerous beyond the major vascular arcades.
There is a strong female predominance. ERG findings suggest a primary involvement of the outer segments of the photoreceptors, namely the level of the cone photoreceptors outer segments.
MEWDS is usually a self-limited disease and recovery of visual function occurs over several weeks. There is a chronic form of MEWDS that has multiple recurrences over many years and involving both eyes.
The cause is unknown.
The differential diagnosis of MEWDS includes acute posterior multifocal placoid pigment epitheliopathy, acute retinal pigment epithelitis, birdshot retinochoroidopathy, multifocal choroiditis, sarcoidosis, diffuse unilateral subacute neuroretinitis, ocular infiltration by lymphoma, acute macular neuroretinopathy, and acute zonal occult outer retinopathy.