ICGA in inflammatory diseases

AbstractPurpose Choroidal involvement in uveitis is present at least as often if not more often than retinal involvement. Imaging of the different choroidal compartments is only possible using indocyanine green angiography (ICGA). The trend presently seems to shift away from ICGA for diseases of the fundus. Unlike other fundus conditions where use of ICGA is debated, this imaging technique is crucial for inflammatory conditions in order not to miss choroidal involvement especially in diseases where the primary lesion process is exclusively situated either in the choroidal stroma as for Vogt‐Koyanagi‐Harada (VKH)disease or at the level of the choriocapillaris as for MEWDS or APMPPE.Methods ICGA is ideal to explore the choroid as the ICG molecule has two crucial properties : (1)it fluoresces in the infrared, allowing to "see" through the RPE into the choroid; linked to proteins it forms a macromolecular complex that is trapped in the choroidal stroma so outlining inflammatory foci. Hence, different lesion processi were identified by ICGA which allowed a classification of choroiditis into choriocapillaritis and stromal choroiditis according to the anatomic location of the disease. Mostly these lesions are occult and can only be identified by ICGA.Results Primary choroidal diseases (choriocapillaritis, stromal choroiditis) could only meaningfully be investigated and followed by ICGA. It was found to be diagnostic in a substantial proportion of cases. In those entities such as VKH where the inflammatory insult is exclusively limited to the choroid, ICGA is the only mean to monitor subclinical disease and adjust therapy.Conclusion In inflammatory diseases, unlike in other fields where opinions diverge, ICGA is not only relevant but essential for global appraisal and follow‐up.