Background Many studies suggest the existence of an alteration of the retinal hemoperfusion in primary open-angle glaucoma. The OCT-A is a novel technique that allows to provide information on retinal microcirculation in a non-invasive way, thus it represents a possible imaging target for the early diagnosis and follow-up of glaucoma. The aim of our work is to evaluate the contribution of vascular parameters provided by OCT-A and their diagnostic abilities in the different stages of primary open-angle glaucoma. Method This is a prospective cross-sectional study involving 200 eyes of control subjects and 250 eyes of glaucomatous subjects divided into early glaucoma, moderate glaucoma and advanced glaucoma subgroups. They were assessed for MD, LV by visual field, RNFL and GCC thickness by SS-OCT papillary and macular vascular densities by SS-OCT A. Results OCT-A vessel densities determined in the optic nerve head, in the peripapillary and in the macular regions were significantly lower in glaucomatous eyes. Among the vascular parameters studied the whole image vascular density showed the best diagnostic ability in the discrimination between glaucomatous eyes and healthy eyes with an AUC of 0.949. Nevertheless, the diagnostic ability of vascular parameters remains lower than of the structural parameters RNFL (AUC: 0.981). A significant correlation was found between structural, functional and vascular parameters with r < 0.05. The quadratic non-linear model defines better the relationship between structural, vascular and functional damage in glaucoma. Conclusion The OCT-A plays an important role in the early diagnosis and follow-up of PAOG. It also contributes to the understanding of some aspects of the vascular role in glaucoma.

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Introduction Diabetic retinopathy (DR) increases the risk of blindness by 25 times. Advanced researchs are justified for better management, leading to the role of Optical Coherence Tomography-Angiography (OCT-A), a new non-invasive imaging technique exploring retinal vascularization. Our purpose is to identify microvascular macular anomalies of DR on OCT-A with qualitative and quantitative evaluation of their impact on retinal vascularization. Patients and methods This is a descriptive cross-sectional study where 120 eyes of 66 diabetic patients were enrolled. All patients were diabetic and went through OCT-A imaging. Results Microanevrysms were identified in both superficial capillary plexus (SCP) and deep capillary plexus (DCP) where they were more frequently visualized. Macular edema was present in 16,7% of cases in the SCP, and in 30% in DCP. Edema spaces were more frequently present in DCP (p < 0,05). Capillary nonperfusion areas were identified in 82,5% of cases in SCP and in 60% of cases in DCP. The main peri-foveal vascular density was 18,95 ± 5,37%. The main surface of foveal avascular zone (FAZ) in the SCP was 462,52 μm 2 and was 555,04 ± 329,11 μm 2 in the DCP where it was larger. Conclusion OCT-A is a modern imaging tool that could be used for the diagnosis and monitoring of DR as well as the understanding of its pathophysiology.