Multiple Evanescent White Dot Syndrome (MEWDS) was first described by L M Jampol et al. in 1984.
Patients commonly present with acute unilateral painless decreased vision and photopsias. Presentations like central or paracentral scotoma, Floaters and dyschromatopsia are less common. An antecedent viral prodrome occurs in approximately one-third of cases. Myopia is commonly seen in patients.
Eye exam during the acute phase of the disease reveals multiple discrete white to orange spots at the level of the RPE or deep retina, typically in a perifoveal location (around the fovea). Optic disc oedema may also seen occasionally.
Source : Wikpedia
It's often accompanied with flu-like symptoms, and predominantly affects women between 15 and 50. The prevalence is unclear, but It's been called the 'Common Cold of the Retina'.
The causes are unknown.
Also see : MEWDS J Ophthalmic Vis Resv.12(2); Apr-Jun 2017