Follow‐up study of MEWDS using adaptive optics retinal imaging

Abstract

AbstractPurpose To study the effects of pathological damage in cone photoreceptor outer segments (OS) on the visibility of cones in adaptive optics (AO) images.Methods Four patients with multiple evanescent white dot syndrome (MEWDS) underwent multimodal retinal imaging using optical coherence tomography (OCT), scanning laser ophthalmoscopy (SLO). AO images were acquired with a field of 4 x 4 deg at eccentricities ranging from 0 to 8 deg from fovea using an infrared flood‐illumination AO camera (rtx1, Imagine Eyes, France). Cone phoreceptor density was measured and analyzed in comparison to the findings from the other imaging modalities. The procedure was repeated at a follow‐up visit after one month. One patient had 3 additional follow‐up examinations over a 10‐month time.Results OCT images showed irregularities and disruptions in the OS tip line. Local thinning of the OS layer was observed in several areas of the macula. AO images revealed marked decreases in the density of detectable cones in the exact same regions. The measured cone density was superior to 30000 cells per mm2 in the areas of normal OS length and dropped to less than 10000 cells per mm2 in the regions of shortened OS. The locations of cone mosaic defects in the AO images also corresponded with hypo‐fluorescent areas observed in the late phase of ICG angiography. During clinical recovery, the progressive return of the IS/OS and the OS tip lines to a normal layered structure in OCT images was correlated to an increase in cone density in AO images.Conclusion AO imaging facilitates detection and monitoring of damage and recovery of the photoreceptor OS during MEWDS. The visibility of cones in AO images seems to be strongly dependent on OS structure and length.