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Background: Diabetic retinopathy is a common deficiency of diabetes mellitus. Diabetic macular ischemia [DMI] is a permanent form of diabetic maculopathy, and its presence reduces the potential benefits of diabetic retinopathy management. Optical coherence tomography [OCT] is used to precisely and reliably measure the macular thickness and outline the retinal layers. Optical coherence tomography angiography [OCTA] can be utilized as a reliable tool to classify the superficial capillary plexus [SCP], the deep capillary plexus [DCP] and the capillary non-perfusion [NP]. Aim of the work:The current research aimed to investigate the correlation between macular non-perfusion that diagnosed by OCTA and patterns of macular layers that diagnosed by OCT scans through the same parts, in a trial to help in the evaluation of both structural and vascular integrity. Patients and Methods:The study included 250 eyes of 125 diabetic patients. All study participants were scanned by OCTA. OCT angiograms were re-sampled with OCT scans from the same region, permitting synchronous evaluation of structure and blood flow.Results: 250 of 125 diabetic patients were categorized into two groups according to capillary NP, ischemic [G1] and non-ischemic [G2].In current study the incidence of DMI was 40%. The incidence of DCPNP was 100% in eyes with DMI while the incidence of SCPNP was 71%. The incidence of foveal avascular zone [FAZ] irregularity, disorganization of the retinal inner layers [DRIL], inner/outer segment IS/OS and external limiting membrane ELM disruptions were 100%, 83%, 95%, 71% respectively among eyes with DMI. DCPNP was more found in all eyes with FAZ irregularity, DRIL, IS/OS and ELM disruption than SCP NP which makes it as the central cause of structural changes in the retina during ischemia. There was a strong positive correlation between the appearance of FAZ irregularity, DRIL, IS/OS and ELM disruption with each of the duration and severity of DR. Conclusion:FAZ irregularity, DRIL, IS/OS and ELM disruption are considered reliable OCT/OCTA findings that reflect an underling DMI and their existence can influence the visual prognosis.

Background: Glaucoma is a known cause of irreversible blindness worldwide. Several techniques are used for its diagnosis and follow-up. Optical coherence tomography angiography (OCTA) is new technology that provides a quantitative assessment of the microcirculation of the retina and optic nerve in a rapid, noninvasive method. Objective: To evaluate the changes at the macular vessel density (MVD) in primary open glaucoma patients (POAG) to correlate these changes with the changes of both ganglion cell complex (GCC) thickness and retinal nerve fiber layer (RNFL) thickness. Patients and Methods: Fifty healthy participants and fifty primary open angle glaucoma (POAG) subjects underwent visual field analysis, measurement of the whole image MVD, measurement of the average (RNFL) thickness, and measurement of the average thickness of (GCC). The area under the curve (AUC) was assessed for each parameter to differentiate POAG from healthy eyes. Results: MVD was lower in POAG than in the control group. The glaucomatous group showed that MVD was 21.18 ± 2.6 at the fovea, while it was 39.5 ± 4.71 at the parafovea. There was a statistically significant positive correlation between MVD (foveal and parafoveal (especially at the superior quadrant) and the mean deviation (MD) (R+ve, P < 0.05). There was a statistically significant positive correlation between MVD and structural parameters. The ROC curves showed that the cut-off points were < 28.2 and < 48 for MVD at the fovea and parafoveal area respectively, at the superficial vascular plexus with 100% sensitivity & 100% specificity between the controls and POAG eyes. Conclusions: MVD was reduced in cases with POAG compared to the control group. The assessment of macular vessel density by OCTA gave us good diagnostic abilities for diagnosis and management of glaucoma.