Purpose: To study whether the use of macular grid photocoagulation 3 weeks subsequent to the initial intravitreal bevacizumab (IVB) injection for the treatment of diffuse diabetic macular edema can provide a longer disease-free intervals and reduce the burden of more frequent injections.
Methods: A prospective pilot study that included 22 patients with bilateral diffuse diabetic macular edema. In each patient, one eye was treated with repeated IVB injections alone (IVB group), while the other eye was treated with repeated IVB injections in addition to macular grid photocoagulation once only 3 weeks after the initial IVB injection (combined group). Before each IVB injection and during the follow-up visits, all patients received a complete ophthalmic examination. The central macular thickness was measured by optical coherence tomography at baseline and during the follow-up examinations. Fundus fluorescein angiography was performed at baseline and before each IVB injection, to detect and assess macular leakage. All patients were followed-up monthly for at least 12 months after the initial IVB injection and for 3 months after the last IVB injection.
Results: By the end of the follow-up duration (14.2 ± 1.91 months), the mean number of injections was significantly lower (P < 0.05) in the combined group (2.36 per eye) than in the IVB group (3.27 per eye). The mean duration between the injections was significantly longer in the combined group than in the IVB group (P < 0.05). Within each group, the difference between the mean central macular thickness at the baseline and at the end of the follow-up duration was statistically significant (P < 0.05). The change in the mean best-corrected visual acuity between the baseline and the end of the follow-up period was not statistically significant in both the groups (P > 0.05). There was no statistically significant difference between the 2 groups of the study as regards the number of patients who gained, maintained, or lost vision (P > 0.05).
Conclusion: Repeated IVB injection could provide a long-term benefit for the treatment of diffuse diabetic macular edema. Performing macular grid photocoagulation once only 3 weeks subsequent to the initial IVB injection might provide a longer disease-free intervals and reduces the burden of more frequent injections.