Initial macular thickness and response to treatment in diabetic macular edema.

PURPOSE: To assess the effect of initial central macular thickness (CMT) on the response to treatment in diabetic macular edema. METHODS: The data of 150 eyes of 129 patients with clinically significant diabetic macular edema and no previous treatment who had been randomly assigned in the original trial to 1 of the 3 groups, 1) intravitreal bevacizumab (IVB) group (50 eyes); 2) combined intravitreal bevacizumab and triamcinolone (IVB/IVT) group (50 eyes); and 3) macular laser photocoagulation group (50 eyes), were reevaluated. This time the data of the cases were reanalyzed based on their initial CMT. Accordingly, the original treatment groups were categorized into 3 subgroups: 1) <250 µm, 2) 250 µm to 349 µm, and 3) ≥350 µm. Visual acuity and CMT changes in response to different treatments were compared. Main outcome measures were changes in visual acuity and CMT at Weeks 6, 12, 24, and 36. RESULTS: At 6 weeks in all subgroups, mean visual acuity improvement in the IVB group was significantly greater than the other groups (P = 0.002, P = 0.003, P < 0.001, for subgroups of <250, 250-349, and ≥350 µm, respectively). At 12, 24, and 36 weeks in the subgroup >350 µm and at 24 weeks in the subgroup 250 µm to 349 µm, the difference of mean visual acuity changes among the groups reached to a significant level (P = 0.010, P = 0.028, P < 0.001, and P < 0.001, respectively) in favor of the IVB group. The difference in mean CMT changes at 6 weeks and 12 weeks was significant among the groups in the subgroup ≥350 µm (P < 0.001 and P < 0.001) in favor of the IVB group and in the subgroup 250 µm to 349 µm at 24 weeks in favor of combined IVB/IVT group (P < 0.001). CONCLUSION: In the primary treatment of diabetic macular edema, initial CMT may be an important factor in decision making. Regardless of initial CMT, IVB caused a better visual outcome only at 6 weeks. With longer follow-up, however, IVB was superior to IVB/IVT and macular laser photocoagulation only in the eyes with initial CMT of ≥350 µm. Concerning CMT reduction, this superiority of IVB in the eyes with initial CMT of ≥350 µm was not observed beyond 12 weeks.

Randomized trial of intravitreal bevacizumab alone or combined with triamcinolone versus macular photocoagulation in diabetic macular edema.

PURPOSE: To compare the results of intravitreal bevacizumab (IVB) injection alone or in combination with intravitreal triamcinolone acetonide (IVT) versus macular laser photocoagulation (MPC) as a primary treatment of diabetic macular edema (DME). DESIGN: Randomized 3-arm clinical trial. PARTICIPANTS: A total of 150 eyes of 129 patients with clinically significant DME and no previous treatment. METHODS: The eyes were randomly assigned to 1 of the 3 study arms: the IVB group, patients who received 1.25 mg IVB (50 eyes); the IVB/IVT group, patients who received 1.25 mg of IVB and 2 mg of IVT (50 eyes); and the MPC group, patients who underwent focal or modified grid laser (50 eyes). Retreatment was performed at 12-week intervals whenever indicated. MAIN OUTCOME MEASURES: Change in best-corrected visual acuity (VA) at week 24. RESULTS: VA changes among the groups were statistically significant at 6 (P<0.001) and 24 (P = 0.012) weeks. The significant treatment effect was demonstrated in the IVB group at all follow-up visits and in the IVB/IVT group at 6 and 12 weeks. VA changes +/- standard deviation at 36 weeks were -0.28+/-0.25, -0.04+/-0.33, and +0.01+/-0.27 logarithm of minimum angle of resolution in the IVB, IVB/IVT, and MPC groups, respectively (P = 0.053). Significant central macular thickness (CMT) reduction was observed in all groups only up to 6 weeks; however, CMT changes were not significant among the groups in all visits. Overall, retreatment was required for 27 eyes up to 36 weeks (14 in the IVB group, 10 in the IVB/IVT group, and 3 in the MPC group). In the IVB group, in which a greater VA improvement was observed, only 1 injection was required in 72% of the cases. VA improvement >2 Snellen lines at 36 weeks was detected in 37%, 25%, and 14.8% of patients in the IVB, IVB/IVT, and MPC groups, respectively. CONCLUSIONS: Intravitreal bevacizumab injection in patients with DME yielded a better visual outcome at 24 weeks compared with macular photocoagulation. A change in CMT beyond the 6-week time point that corresponded to the vision change was not detected. No adjunctive effect of IVT was demonstrated. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.