Purpose: To evaluate the efficacy of intravitreal injection of bevacizumab (IVB) followed by modified grid laser photocoagulation (MGP) versus each alone as a primary treatment of diffuse diabetic macular edema.
Patients and methods: A randomized 3-arm clinical trial in which 62 eyes of 48 patients with diffuse diabetic macular edema were enrolled. Eyes were randomly distributed to 1 of 3 study groups: 19 eyes underwent MGP (MGP group), 21 eyes received 1.25 mg of IVB (IVB group), and 22 eyes received IVB followed by MGP (combined group). All eyes underwent a complete ophthalmic examination including fluorescein angiography and optical coherence tomography at baseline and at 1, 3, and 6 months, after treatment. Fluorescein angiography was performed at the 3 and 6 months follow up visits. The outcome measures were the change compared with baseline in central macular thickness (CMT), changes in best-corrected visual acuity (BCVA), changes in fluorescein angiography leakage, and any reported complication. A P value less than 0.05 was considered statistically significant.
Results: One month after treatment, the reduction in the mean CMT versus baseline was 49.88 μm (10.45%) in MGP group, 150.92 μm (31.30%) in IVB group, and 110.30 μm (23.77%) in the combined group, with a corresponding improvement in the mean BCVA. At 1 month, the improvement in CMT was better than baseline in all groups, yet only significant in the IVB group (P < 0.05) and the combined group (P < 0.05). The improvement in mean BCVA was significant in the IVB (P < 0.05) and the combined groups at 1 month (P < 0.05). At 3 months, the mean CMT was still better than baseline in all groups but this improvement was significant only in the combined group (P < 0.05). The improvement in the mean BCVA was significant only in the IVB and the combined groups (P < 0.05). Six months after treatment, the reduction in the mean CMT was significant in the combined group only (P < 0.05) and there was no significant improvement in the mean BCVA in all groups (P > 0.05). The BCVA did not deteriorate below baseline in all eyes included in the study, except three eyes in the MGP group. No complication related to the intravitreal injection was reported in the injected eyes.
Conclusion: Combined therapy with IVB and sequential MGP 3 weeks later appeared to be superior to MGP or IVB alone in reducing macular thickening and improving visual acuity. However, no significant improvement in BCVA occurs 6 months after treatment. A combination of IVB and sequential MGP could be used as an initial treatment of diffuse diabetic macular edema.