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Sonja Karst, Morgan Heisler, Natalia Page, Timothy Yu, Julian Lo, Mahyar Etminan, Marinko V Sarunic, David Maberley, Eduardo Vitor Navajas; Evaluating signs of microangiopathy secondary to diabetes in different areas of the retina with swept source OCTA. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5349.
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© ARVO (1962-2015); The Authors (2016-present)
Capillary density measurements were so far only performed around the fovea, but changes secondary to diabetes are frequently observed more peripheral. In this cross-sectional clinical study we compared the perfusion parameters of the parafovea with more peripheral scans to find an area that is most susceptible to changes secondary to diabetic retinopathy (DR).
Patients with diabetes and DR of different severity levels as well as healthy controls were included. Seven standardized 3x3 mm areas were recorded with Swept Source Optical Coherence Tomography Angiography (Plex Elite 9000 ©, Zeiss Meditec): one was centered on the fovea, three were recorded at a distance of 15.8 degree temporal to the fovea and three were recorded nasally to the optic disc. The capillary networks were segmented in processed in MATLAB. The capillary density (CD) of the superficial and deep vascular complex (SVC, DVC) as well as the mean capillary diameter were generated after subtracting the area occupied by bigger blood vessels. Analysis of variance was used to compare perfusion parameters of different areas and DR severity levels (SPSS, version 25).
70 eyes of 45 patients and 28 eyes of 19 controls were included (59 ± 14 years, 23 female). Mean CD of the SVC was significantly less in the temporal areas (0.469, 0.461, 0.411, 0.369 in control, mild, moderate/severe and proliferative DR, respectively) compared to the parafovea (0.497, 0.486, 0.463, 0.433369 in control, mild, moderate/severe and proliferative DR, respectively) in all patients. In healthy controls, the CD in the DVC was comparable in all areas (p=0.207) but with disease progression it seemed to decline in the nasal areas first. There was a significant difference in CD of the SVC and DVC as well as in the fractal dimension between mild and moderate/severe DR in all areas but the mean capillary diameter did not seem to be affected.
CD of the SVC was less temporal to the fovea while the CD of the DVC was comparable in all areas measured in healthy controls. With DR progression CD of the DVC declined earlier in areas nasal to the optic disc compared to the parafovea. CD of the SVC and DVC as well as the fractal index seem to be valid biomarkers to identity mod/severe DR. Scanning different retinal areas might help to detect early microvascular changes secondary to DR.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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