OCT Angiography Biomarkers in Diabetic Macular Edema Patients Treated with Intravitreal Injection of Anti-VEGF

Abstract Purpose To correlate quantitative OCT angiography (OCTA) biomarkers with clinical features and to predict the responce after ranibizumab treatment for diabetic macular edema (DME) with OCTA biomarkers. Design Non randomized non controlled observational study on 20 eyes with DME set in the Ophthalmology Department, Ain Shams University. Study subjects were selected randomly from patients attending the ophthalmology outpatient clinics during the recruitment period, which took place between December 2020 and December 2022. Participants The study was conducted on twenty eyes from 20 patients of with diabetic macular edema, with the exception of media opacity and high refractive error, from Ain Shams University hospital. Methods All patients underwent Spectral Domain Optical Coherence Tomography (SD-OCT) (RTVue XR OCT Avanti; Optovue, Fremont, USA) with Macular scan including 6x6mm scans centered on the fovea at baseline evaluation and at 1 month, 3 months and 6 months while on treatment with intravitreal antiVEGF (Ranibizumab) injections following the PRN protocol without loading. Main Outcome Measures OCTA biomarkers, including foveal avascular zone (FAZ) area (FAZ-A), FAZ acircularity index (FAZ-AI), FAZ perimeter and vessel density (VD), were analyzed comprehensively. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) also were obtained. Results After the ranibizumab treatment, there was a statistically significant decrease in the FAZ area and FAZ perimeter during the follow up period denoting improved vascular perfusion, and the FAZ AI decreased significantly denoting that the FAZ regained its regularity. There was a statistically significant increase in the mean vessel density including the overall, parafoveal and perifoveal vessel density in the superficial and deep plexus during the follow up period, this might be explained by decreased artifacts due to macular edema. There was a statistically significant difference in the parafoveal vessel density in the SCP, FAZ area, FAZ perimeter, and AI at baseline between good and poor responders. These biomarkers could be used as predictors for response after treatment with anti VEGF in eyes with DME. Conclusions For eyes with DME, parafoveal VD in the superficial layer, FAZ area and perimeter at baseline were independent predictors for visual improvement after the ranibizumab treatment.