Review on imaging methods in non-infectious posterior uveitis, principles, relevance, and practical clinical applications to disease entities

The work-up and diagnosis of posterior uveitis rely heavily on multiple imaging methods that have become available beyond the mere photographic imaging and fluorescein angiography (FA) used to image uveitis in the past. Global assessment and precise follow-up of posterior uveitis were achieved with the development of indocyanine green angiography (ICGA) since the mid-1990ties that, together with FA, made it possible to perform dual FA and ICGA giving information on both the retina and the choroidal compartment. Further non-invasive imaging methods were developed subsequently that contributed to additional valuable information completing the dual FA/ICGA basic appraisal of uveitis, including (1) optical coherence tomography (OCT) giving a quasi-histological  morphology of retinal structures of the posterior pole, (2) enhanced-depth imaging OCT (EDI-OCT) allowing to image the choroidal compartment and (3) blue light fundus autofluorescence (BAF) showing the integrity or damage of the retinal pigment epithelium, the photoreceptors and the outer retina. OCT-angiography (OCT-A) became available more recently and presented the advantage to image the retinal and choroidal circulations without needing dye injections, necessary for dual FA/ICGA. This review article will illustrate the principles, relevance and practical applications of these different imaging methods used in uveitis by examining the main categories of  non-infectious posterior uveitis entities including (1) retinal inflammatory disorders, inflammatory diseases of the outer retina and of the choriocapillaris (choriocapillaritis) and stromal choroiditis.