Comparison of Dexamethasone Implant Followed by Bevacizumab versus Bevacizumab Monotherapy for Diabetic Macular Edema

Purpose: To compare the efficacy of initial single intravitreal dexamethasone implantation followed by bevacizumab compared with bevacizumab monotherapy for diabetic macular edema (DME). Methods: Twenty-eight patients with DME who were followed for at least 6 months were divided into two groups: bevacizumab monotherapy (BVZ group, 15 eyes) and intravitreal dexamethasone implantation followed by bevacizumab (DEX group, 13 eyes). The BVZ group underwent pro re nata (PRN) injections of intravitreal bevacizumab, while the DEX group underwent initial single intravitreal dexamethasone implantation followed by bevacizumab PRN injection. Outcome measures included visual acuity (logarithm of the minimal angle of resolution, logMAR) and anatomical changes on optical coherence tomography. Results: Mean best-corrected visual acuity (BCVA) was significantly improved in both groups, but there was no significant difference in BCVA between the two groups during the follow-up period. Mean central macular thickness was also significantly decreased in both groups, and was thinner in the DEX group (p < 0.001 at 1 month, p = 0.020 at 5 months, p = 0.046 at 6 months). The overall average number of injections during the follow-up period was significantly lower in the DEX group (2.60 0.84 vs. 3.87 1.18, p = 0.008). At 1 month, the rate of complete absorption of macular edema was significantly higher in the DEX group (p = 0.028). The rate of cataract-related adverse events in phakic eyes was 0.0% in both groups, and there was no significant difference between groups in the rate of increased intraocular pressure (IOP), both of which were controlled by medical treatment. Conclusions: Initial single intravitreal dexamethasone implantation followed by bevacizumab PRN injection in DME showed better anatomical improvement with less recurrence on short-term follow-up than treatment with bevacizumab PRN monotherapy.