Purpose: The purpose of this study was to evaluate the effectiveness of intravitreal bevacizumab (IVB) on the reduction of diffuse diabetic macular edema in patients with different optical coherence tomography patterns.
Design: Prospective interventional case series.
Methods: One hundred and forty-three eyes with diffuse diabetic macular edema, without a history of any previous treatment, were classified according to their optical coherence tomography patterns: sponge-like diffuse retinal thickening (SDRT) (n = 50), cystoid macular edema (CME) (n = 38), serous retinal detachment (SRD) (n = 25), and the combination of all patterns (FULL: n = 30). All the participants received a single dose (1.25 mg in 0.05 mL) of IVB. The foveal thickness obtained with optical coherence tomography images and logarithm of the minimum angle of resolution visual acuity were assessed before receiving IVB and subsequently every 2 weeks for 12 weeks.
Results: After IVB, the foveal thickness in all the groups was reduced but the reduction ratio in the SDRT (29.6 ± 15.6%) and CME (27.1 ± 20.5%) groups was significantly greater than in the SRD group (16.4 ± 17.7%) (P < 0.001). Similarly, improvement of visual acuity in the SDRT (−0.21 ± 0.16) and CME (−0.17 ± 0.24) groups was significantly greater than in the SRD (−0.12 ± 0.15) and FULL (−0.11 ± 0.13) (P = 0.047) groups. Interestingly, the efficacy of IVB for regression of diffuse diabetic macular edema was dependent on the duration of diabetes in the SDRT and CME groups but not in the SRD or FULL groups.
Conclusion: The effectiveness of IVB on diffuse diabetic macular edema was dependent on the optical coherence tomography pattern (SDRT ≥ CME >> SRD), indicating that vascular endothelial growth factor plays a critical role in the pathogenesis of SDRT and CME, and was greater in patients having diabetes for a shorter duration of time.