Diabetes mellitus (DM) stands out as one of the chronic diseases with the highest morbidity and mortality rates worldwide. Among the many complications of DM, diabetic retinopathy (DR) is one of the causes of blindness in patients aged between 20 and 64 years. At least 90% of the new cases showed to have the retinal structure and function restored when proper treatment was provided. To evaluate the efficacy of the antiangiogenic bevacizumab in the treatment of DR according not only to the clinical laboratory parameters for glycated hemoglobin (HbA1C) and capillary glycemia but also to the ophthalmological parameters for optical coherence tomography (OCT) and best-corrected visual acuity (BCVA). A total of 11 individuals were included and followed up for 12 months after 3 administrations of bevacizumab. Upon associating the ophthalmological and laboratory variables throughout the treatment, no significant alterations could be seen regarding the analyzed variables. However, it was observed that HbA1c values and the total leukocyte count negatively interfered with the treatment response. The current study showed that HbA1c values and the amount of leukocytes negatively interfere with the therapeutic response. Therefore, laboratory analyses of these parameters are recommended for diabetic patients undergoing the above-mentioned treatment.