Evaluation of retinal anatomical, functional and vascular changes after intravitreal bevacizumab treatment in patients with diabetic macular edema

Evaluation of Retinal Anatomical, Functional and Vascular Changes After Intravitreal Bevacizumab Treatment in Patients with Diabetic Macular Edema Diabetic retinopathy (DRP) is the most common microvascular complication of diabetes mellitus (DM) and the most common cause of blindness in the working age group. In this study we aimed to determine the retinal anatomical, functional and vascular changes after the intravitreal bevacizumab treatment in patients with diabetic macular edema (DME), by optical coherence tomography (OCT), microperimetry (MP) and optical coherence tomography angiography (OCTA) respectively, whether or not this changes are correlated with the increment of the visual acuity. A prospective interventional study was planned for 31 eyes of 31 patients with diabetic macular edema who had not received any treatment previously. Patients who met the criteria were given 3 doses of intravitreal bevacizumab injection one month apart. The best corrected visual acuity (BCVA) was recorded; fundus fluorescein angiography, optical coherence tomography, microperimetry and optical coherence tomography angiography were evaluated before and after treatment. The patients were grouped according to the increase in visual acuity after 3 consecutive injections as follows; group 1 with the patients whose BCVA increased more than 10 letters, group 2 with the patients whose BCVA increased less than 5 letters, group 3 with the patients whose BCVA increased between 5-10 letters. While the mean initial BCVA was 34.2 letters, increased to 39.9 letters after treatment (p <0.001). Intraocular pressure changes was not statistically significant (p = 0.665). Mean initial central macular thickness (CMT) was 335.1 μm, whereas mean CMT was measured as 276.4 μm after treatment. There was a statistically significant decrease in CMT between baseline and 3rd month values (p <0.001). Significant improvements in fixation stability were observed in microperimetry tests at 3rd month after treatment. The mean retinal sensitivity increased from 8.2 decibels (dB) to 11.2 dB and was statistically significant (p <0.001). Mean local defect increased from -10.7 dB to -7.9 dB and was statistically significant (p <0.001). No significant change was observed in the data obtained with OCTA after treatment. There was no statistically significant difference between the groups in terms of age, gender, on the baseline mean BCVA, mean HbA1c, mean intraocular pressure, phakic / pseudophakic lens ratio, presence of concomitant hypertension and superficial capillary plexus vascular density. When the data obtained with OCTA were examined, it was observed that the patients with low foveal avascular zone (FAZ) area, high FD-300 values and high deep plexus vascular density values ameliorated better in terms of visual acuity, mean retinal sensitivity and local defect values after the intravitreal bevacizumab treatment. In patients with DME, intravitreal bevacizumab treatment provide significant increase in visual acuity, significant improvement in OCT findings which shows anatomical and structural integrity and MP-1 findings which is indicator of the functional state of the retina. It has been observed that functional improvement correlates with structural improvement and can be predicted with OCTA findings.