MEWDS is a true primary choriocapillaritis and basic mechanisms do not seem to differ from other choriocapillaritis entities

• Published in: Iranian journal of ophthalmology 2018-12, Vol.30 (4), p.281-286
• Main Authors: Lages, Vânia, Mantovani, Alessandro, Papadia, Marina, Herbort, Carl P.
• Format: Article
• Language: English
• Subjects: Diabetic retinopathy; Edema; Hypotheses; Medical imaging; Pathology; Patients; Photoreceptors
• ISSN: 2452-2325; 2452-2325
• DOI: 10.1016/j.joco.2018.09.009

Most reports for nearly three decades have interpreted these ICGA signs as choriocapillaris non-perfusion. [...]it is very unlikely that these ICGA findings are suddenly attributed to a new, questionable mechanism solely for MEWDS and not other choriocapillaritis entities.Different choriocapillaritis entities can occur in the same patient In addition to similar nosological characteristics, indicating a similar physiopathological process and the involvement of a similar structure, namely the choriocapillaris, numerous reports have shown that more than one type of choriocapillaritis can occur in the same patient,15–20 underlining the unitarian character of this group of disorders. OCT-A generates images of the retinal and choroidal vasculature by detecting the movement of red blood cells inside the vessels between two consecutive scans of the same area.21 As this method detects vascular blood flow within a determined time frame, there is a slowest and fastest detectable blood flow.22 If the vascular flow is outside this range, the OCT-A will not capture it. [...]ICGA hypofluorescent areas can not be explained by a masking effect or a speculative lack of indocyanine fixation. The device is excellent for analyzing retinal perfusion, including superficial and deep retinal circulation, as well as choroidal neovessels, where flow is substantial. [...]the device is very much suited for analyzing retinal perfusion in diabetic retinopathy, where it can show rarefication of peri-foveal vessels, as well as following high-flow neovessels in wet age-related macular degeneration.30,31 In contrast, the choriocapillaris is characterized by a low pressure/low flow and labile circulation, especially in its terminal network and, therefore, is probably not detected by OCT-A.