Optical coherence tomography patterns of diabetic macular edema and treatment response to bevacizumab: a short-term study

Abstract

Background: The purpose of this study was to evaluate the short-term response of intravitreal bevacizumab in diabetic macular edema (DME) and assess the variation in treatment outcomes in different morphology patterns using spectral domain–optical coherence tomography (SD-OCT). Objective: To study different morphological patterns of DME based on OCT and compare their treatment response to bevacizumab. Methods: Hundred and twelve eyes of 112 patients with DME were included and treated with intravitreal bevacizumab (1.25 mg/0.05 ml monthly for 3 months). The morphological patterns of DME were classified on the basis of OCT into three groups – diffuse retinal thickening (DRT), cystoid macular edema (CME), and serous retinal detachment (SRD) – and changes in central macular thickness (CMT) and best corrected visual acuity (BCVA) after treatment were compared. Results: A total of 112 eyes with DME were included and consisted of 40 DRT, 37 CME, and 35 SRD. Treatment with bevacizumab resulted in decrease in central macular thickness and improvement in BCVA in all three groups. The baseline visual acuity and CMT of DRT group was better than that of the other two groups. The treatment outcome was measured in terms of CMT and BCVA. Change in CMT was statistically significant among three groups and was found to be better in DRT group (p < 0.05, 95% confidence interval). However, there was statistically no significant variation between the three groups regarding the change in BCVA (p = 0.169, 95% confidence interval). Conclusion: Anatomic and visual improvement can be achieved by bevacizumab in all patterns of DME. However, individual pattern may respond differently. DRT, which appears to be the earliest form of DME, responds better than other types. Thus, the pattern of macular edema shown by OCT may provide an objective guideline in predicting the response of bevacizumab injection in DME.