Optical Coherent Tomography-Angiography in the Research of Myopia Complicated by Choroidal Neovascularization

Abstract

Purpose: to determine the features of myopic choroidal neovascularization (mCNV) using optical coherent tomography-angiography (OCTA) in patients with complicated myopia during anti-VEGF therapy.Patients and methods. A prospective study of 25 people (40 eyes) with complicated myopia was carried out, which consisted in a comparative analysis of the qualitative and quantitative OCTA characteristics of 29 eyes with myopic CNV and 11 paired intact eyes. OCTA was used in the Angio Retina and Angio Analytics modes based on automatic software. The phenotypic features of CNV before treatment, during anti-VEGF therapy (Ranibizumab) and at the end of the observation period were taken into account.Results. The average follow-up period is 26.12 (12.36; 35.02) months. Two mCNV phenotypes were established: glomerular (44.83 %) and flat (55.17 %) as regularized (18.75 %) and tangled (81.25 %) vascular network patterns. Hypointensive peripheral halo during the entire period of the neovascular complex activity was visualized regardless of the phenotype. Significant differences in the flat phenotype were revealed: neuroepithelial detachment (87.50 %) was more common, the Select Area and Flow Area of the neovascular complex was significantly greater both before treatment and at the end of the observation period, the mCNV course of continued growth after injection of anti-VEGF did not occur, recurrence rate is much higher. The area and perimeter of the foveal avascular zone (FAZ) in the eyes with mCNV increased significantly by the end of the observation. The acirculatory index (AI) was determined to be significantly higher, and the Retinal capillary flow density in the fovea region 300 μm wide around the FAZ (FD) was lower in the eyes with mCNV compared to the control group. The nonactive neovascular complex were characterized by depletion of the vascular network with a predominance of intervascular space, vessels in the form of a residual skeleton, blindly end, dim, small capillaries and end loops are missing. Halo with nonactive CNV is not found.Conclusion. OCTA identifies the features of the course of myopic CNV depending on the phenotype, allows to evaluate the effectiveness of anti-VEGF therapy and the degree of progression of degenerative changes in the macular region.