Intravitreal bevacizumab and dexamethasone implant for treatment of chronic diabetic macular edema

To evaluate anatomical and functional outcomes of intraviteal bevacizumab (IVB) in patients with chronic diabetic macular edema (DME), and the effectivity and safety of dexamethasone implant in those unresponsive to regular IVB treatment.

Thirty-five eyes of 35 patients (16 male and 19 female) with chronic DME (central foveal thickness (CFT)  > 275 μm, duration  > 6 months) received three injections of 2.5 mg IVB with six-week intervals. At 18 weeks, dexamethasone implant was applied to patients unresponsive to IVB. Main outcomes were the change in best corrected visual acuity (BCVA), CFT and ocular and systemic adverse effects for both drugs. The patients responsive to IVB were followed up for 36 weeks and those patients receiving dexamethasone implant were followed up for 24 weeks postoperatively.

At 18 weeks, the mean BCVA (0.68 ± 0.40 logMAR, p = 0.45) and CFT (453 ± 169 μm, p = 0.58) did not show any significant change compared to baseline (0.74 ± 0.42 logMAR and 521 ± 151 μm, respectively). In 20 patients (%57.1) responsive to IVB, the CFT was significantly improved from 12 to 36 weeks with the mean value of 295 ± 42 μ (p = 0.01). However, no significant difference was observed for BCVA during this period (p = 0.17). Dexamethasone was implanted in 15 eyes (42.8%) unresponsive to IVB at 18 weeks. Statistically significant improvements were observed in BCVA (at postoperative 4 and 12 weeks) and CFT (at postoperative 4, 12 and 24 weeks). In addition, both parameters significantly worsened at 24 weeks compared to 12 weeks (p < 0.001 and p = 0.01, respectively).

Patients with chronic DME should be followed in accordance with a fixed treatment protocol combining anti-VEGF and steroid treatments.