Abstract
Background. Diabetic macular ischemia (DMI) and foveal avascular zone (FAZ) enlargement are two important clinical findings and biomarkers of poor visual function in patients with diabetic retinopathy (DR). OCT angiography (OCTA) is a noninvasive technique that allows to visualize the retinal plexuses layer by layer, to quantify microvascular parameters, and to correlate them with functional and morphological data. Research is oriented towards identifying earlier preclinical biomarkers of microvascular abnormality in diabetic retina and diabetic macular edema (DME), which is very important considering that early treatment is associated with better outcome. Aim: to assess the role of central retinal microcirculation indicators in predicting visual functions in patients with different stages of diabetic macular edema in type 2 diabetes. Materials and methods. 680 patients (1296 eyes) with the Ukrainian population with type 2 diabetes mellitus were under observation. DME 0 was diagnosed in 720 eyes (55.56%), DME 1 in 194 eyes (14.97%), DME 2 in 196 eyes (15.12%), DME 3 in 186 eyes (14.35%). From this group of patients, 477 patients (936 eyes) underwent various DME treatment according to treatment protocols for a separate stage of edema. 203 patients (360 eyes) with DME were not treated due to patient refusal, this group of patients was the target of our study. In addition to standard ophthalmological examinations, examination of uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), optical coherence tomography (OCT), OCT angiography, and computer perimetry were performed. The coefficient of microcirculation of the macular area was calculated by the ratio of the area of the foveolar avascular zone (FAZ) to the capillary density (CD) in the superficial (SCP) and deep capillary plexuses (DCS) at different stages of DME. Correlation analysis was used to identify the relationship between features: Spearman's rank correlation index - r was calculated (in the case of a difference in the law of distribution from the normal). Changes of one or another characteristic were considered statistically significant in case of p < 0.05. Results. Indicators of Spearman rank correlation between UCVA, BCVA and the coefficient of microcirculation (FAZ/ CD) in the SCP with DME 0 was rUCVA-FAZ/CD = -0,96, r BCVA-FAZ/CD = -0,97; DME1 - r UCVA-FAZ/CD = -0,88, rBCVA-FAZ/CD = -0,94; DME2 - r UCVA-FAZ/CD = -0,82, r BCVA-FAZ/CD = -0,92; DME3 - r UCVA-FAZ/CD = -0,9, r BCVA-FAZ/CD = -0,82 (p<0,05). Indicators of Spearman rank correlation between UCVA, BCVA and the coefficient of microcirculation (FAZ/CD) in the DCP with DME 0 was rUCVA-FAZ/CD= -0,96, rBCVA-FAZ/CD =-0,98; DME1 - rUCVA-FAZ/CD =-0,88; rBCVA-FAZ/CD=-0,9; DME2 - rUCVA-FAZ/CD =-0,82, rBCVA-FAZ/CD =-0,92; DME3 rUCVA-FAZ/CD =-0,89; rBCVA-FAZ/CD =-0,8 (p<0,05). Conclusion. As a result of our research, a definite negative strong correlation was established between the microcirculation coefficients of the SCP and DCP and visual acuity, which can be considered as a prognostic marker of DME progression in patients with non-proliferative DR and type 2 diabetes