Evaluation of the Effect of Intravitreal Injections of Anti-VEGF on Macular Perfusion in Diabetic Patients Using OCTA

This is a prospective interventional study to evaluate the effect of repeated intravitreal injections of Anti-VEGF on macular perfusion in diabetic patients using optical coherence tomography angiography (OCTA). Each patient will receive a detailed ophthalmologic examination including measurement of BCVA as well as applanation tonometry, undilated and dilated slit-lamp biomicroscopic examination and indirect fundus examination. Duration of diabetes and its control through HbA1C measurement will be recorded for each patient. Type 1 and 2 diabetic patients found to have BCVA worse than 6/6 and clinical evidence of macular edema will undergo SD OCT and FA. Patients with center involved macula edema detected by SD OCT will be included in the study and will undergo baseline macular OCTA. These patients will then undergo intravitreal injections of Anti-VEGF monthly for 3 months then OCTA will be repeated to evaluate changes in macular perfusion and SD OCT will be repeated to assess retinal thickness. Patients with center involving macular edema on SD-OCT after the first 3 injections will continue to receive intravitreal Anti-VEGF injections monthly until the edema subsides or the study duration ends. These patients then undergo a final macular OCTA for perfusion evaluation and SD OCT for thickness assessment. OCTA will be performed with an Avanti RTVue XR system (Optovue, Inc., Fremont, CA, USA). Area of FAZ and capillary density at each capillary layer will be calculated before and after interventions using the OCTA machine software and ImageJ software. All statistical analyses will be done using IBM SPSS v20.0 statistical software (IBM Corporation, NY, USA). Descriptive statistics will be calculated, and the data will be summarized as mean ± SD for numerical data, and as frequencies and percentages for categorical data.