Scanning laser densitometry in multiple evanescent white dot syndrome.

A 28-year-old man with multiple evanescent white dot syndrome (MEWDS) in the left eye was examined with a scanning laser densitometer. The first measurements were taken in the acute stage, and repeat examinations were performed during the process of recovery. Fundus pictures were obtained from a 20 degrees retinal field, in dark and light adapted stages. From these images visual pigment density maps were derived. In the acute stage of the disease, maps revealed small round areas of absent visual pigment, which did not always correspond with the visible white dots. The areas of absent visual pigment density were also larger than the white dots seen on funduscopic examination. Single spot densitometry at the fovea was also performed and showed no significant density difference of the foveal cones. Rod density difference measured at a locus 16 degrees in the temporal retina was much lower than normal with an increased time constant of rhodopsin regeneration. Ten weeks after the onset of the disease, no white dot lesions were visible on funduscopic examination. Rod density difference and regeneration time had become normal again, but with scanning laser densitometry the abnormal areas of no pigment were still faintly visible. It is concluded that these findings, completed with data of electroretinography, anomaloscopic testing, and perimetry, are in agreement with a metabolic disturbance at the level of the retinal pigment epithelium-photoreceptor complex.