The application of optical coherence tomography angiography in uveitis and inflammatory eye diseases

Since its introduction in the early 1990s, optical coherence tomography (OCT) has evolved in resolution and technological advances, and in recent years its initial application of assessing the morphology of a tissue has been implemented by the study of its functional blood flow, through optical coherence tomography angiography (OCTA). This novel technique details capillary networks by comparing the amount of light returned from static and moving targets without the need for intravenous dye administration. While this imaging modality has been used for various ocular conditions, the application OCTA to uveitis conditions remains sparse. This review aims to establish the basis of OCTA and its current application to ocular inflammatory disorders, with an emphasis on monitoring progression and response to treatment, as well as predicting visual complications. In particular, this review explores the use of OCTA in iris vessel dilation seen in various forms of iritis, as a predictive factor for further episodes of inflammation. OCTA can also depict ischemia in the deep plexus layers of the retina and identify true choroicapillaris ischemia in cases of placoid diseases or masking of the indocyanine green dye, as in multiple evanescent white dot syndrome. In addition, OCTA can depict neovascularization in granulomatous disease of the retina or choroid not previously depicted with previous imaging methods. While OCTA provides several advancements in the imaging, management and prognosis of uveitis diseases, we emphasize that further studies are required to fully understand its application to these conditions.