REVIEW  OCT ANGIOGRAPHY: A NEW ERA OF OPHTALMOLOGY 

Minerva Oftalmologica 2018 September;60(3):116-29

DOI: 10.23736/S0026-4903.18.01808-1

Copyright © 2018 EDIZIONI MINERVA MEDICA

language: English

Optical coherence tomography angiography in diabetic retinopathy

Mariacristina PARRAVANO ✉, Daniele DE GERONIMO

Department of Ophthalmology, IRCCS-Fondazione Bietti, Rome, Italy

Optical coherence tomography angiography (OCTA) has been clinically adopted to observe structural pathological vascular changes of diabetic retinopathy (DR) in the posterior pole, as the presence of retinal nonperfusion, changes in foveal avascular zone (FAZ) shape and microaneurysms (MAs) evaluation and may be a very important alternative when fluorescein angiography (FA) cannot be performed. Several studies have been published regarding the OCTA aspect of the retina of diabetic patients with different stages of DR comparing them with FA and SD-OCT images, the gold standard exams in the study of DR, focusing on the capability to visualize typical vascular changes of the retina such as non-prefusion areas, MAs, macular edema or new vessels. Recently several authors reported than OCTA can clearly visualize diabetic retinal nonperfusion areas and that OCTA may be clinically useful to evaluate the microvascular status at the level of different plexa in patients with DR at different stages. By means of OCTA early non-perfusion changes have been also observed in patients with type I diabetes without clinical signs of diabetic retinopathy. FAZ changes such as enlargement and shape changes have been described at the level of different layers with OCTA in patients with diabetic retinopathy at different stages and OCTA seems to be a better tool in detecting early FAZ changes in DR compared to FA. The capability to visualize diabetic MAs with OCTA has been studied and compared with that one of FA and SD-OCT. Several authors reported that most of MAs detected on OCTA are located mainly in the deep plexus (INL) and an association between the distribution of MAs in each capillary plexus layer and diabetic macula edema has been reported. The OCTA features of MAs, compared with SD-OCT characteristics, may help further understand the different pattern of blood flow dynamics in MAs and improve our interpretation of MA detection on OCTA. In the near future OCTA features of the macula of diabetic patients could help us to predict the response to treatment with anti-VEGF. As a matter of fact, a higher number of MAs, a lower vascular flow density, a larger FAZ area in the DCP, and a lower flow density in the total capillary plexus seems to be associated with a poor response to treatment with anti-VEGF agents. In patients with proliferative diabetic retinopathy OCTA, which is unaffected by fluorescein leakage and visualizes the blood flow inside the vessels, could clearly describe the abnormal NVE and NVD vascular structures. In conclusion OCTA has not yet been widely used in everyday clinical practice and has not greatly changed the way we handle patients with DR. However, the possibility of observing the vascular structures of the retina in a new way is allowing us to obtain much more information related to the etiopathogenesis of the DR helping us to better know all the mechanisms that lead to vascular alterations that characterize the different stages of the disease improving our understanding of DR and diabetic macular edema (DME) pathophysiology.

KEY WORDS: Diabetic retinopathy - Tomography, optical coherence - Angiography