Dexamethasone implant as an adjuvant therapy to ranibizumab loading dose in persistent diabetic macular edema

This study evaluates the effectiveness of a single-dose dexamethasone implant (DI) as an auxiliary therapy to continued intravitreal ranibizumab (IVR) treatment in patients with persistent diabetic macular edema (DME).

Twenty-five pseudophakic eyes of 25 patients with DME who underwent a single injection of DI as an adjuvant therapy following an IVR loading dose were examined retrospectively. All patients were treatment naive and had a poor response to a loading dose of three consecutive monthly IVR injections. IVR treatments were continued pro re nata after the DI. The main outcome measures were changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT) at 1, 3, 6 and 8 months post-DI treatment.

After the IVR loading dose, the mean BCVA and CMT were 0.9 ± 0.6 LogMAR and 478.2 ± 107.8 µm, respectively. One month after the DI, the mean BCVA and CMT had improved to 0.6 ± 0.4 LogMAR (p = 0.005) and 313.8 ± 62.7 µm (p < 0.001), respectively. This improvement was maintained with mean 0.8 ± 0.8 IVR injections throughout the follow-up period. The final mean BCVA and CMT were 0.5 ± 0.5 LogMAR and 298.4 ± 71.5 µm. Subgroup analyses revealed that different DME types did not have any effect on CMT or BCVA improvement (p = 0.188, p = 0.136; respectively).

Adding DI results in rapid anatomical and visual improvement in patients who respond poorly to an IVR loading dose. Improvements may be maintained with additional IVR in follow-up.