Dexamethasone implant for refractory macular edema secondary to diabetic retinopathy and retinal vein occlusion

To evaluate the efficacy, timing of retreatment and safety of dexamethasone (DEX) implant on macular edema (ME) secondary to diabetic retinopathy (DME) and retinal vein occlusion (RVO-ME) patients who were refractory to anti-vascular endothelial growth factor (VEGF) treatment.

This retrospective study included 37 eyes received at least one DEX implant treatment for DME or RVO-ME between January 1, 2019, and January 1, 2023. These refractory DME and RVO-ME cases received at least 5 anti-VEGF injections and failure to gain more than 5 letters or a significant reduction in central retinal thickness (CRT). The best corrected visual acuity (BCVA) and CRT were measured at baseline, and at 1, 3, 4 and 6mo post-DEX implant injection. Adverse events such as elevated intraocular pressure (IOP) and cataract were recorded.

For RVO cases (n=22), there was a significant increase in BCVA from 0.27±0.19 to 0.35±0.20 at 6mo post-DEX injection (P<0.05) and CRT decreased from 472.1±90.6 to 240.5±39.0 µm at 6mo (P<0.0001). DME cases (n=15) experienced an improvement in BCVA from 0.26±0.15 to 0.43±0.20 at 6mo post-DEX implant injection (P=0.0098), with CRT reducing from 445.7±55.7 to 271.7±34.1 µm at 6mo (P<0.0001). Elevated IOP occurred in 45.9% of patients but was well-controlled with topical medications. No cases of cataract or other adverse events were reported.

DEX implants effectively improve BCVA and reduce CRT in refractory DME and RVO-ME. Further research with larger cohorts and longer follow-up periods is needed to confirm these findings and assess long-term outcomes.