Safety and long-term efficacy of repeated dexamethasone intravitreal implants for the treatment of cystoid macular edema secondary to retinal vein occlusion with or without a switch to anti-VEGF agents: a 3-year experience

To evaluate the safety and efficacy of repeated dexamethasone intravitreal implants (DEX implants) over 3 years in eyes with macular edema (ME) secondary to branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO).

We conducted a 3-year, retrospective, multicenter study that included adult patients with ME secondary to BRVO or CRVO treated with first-line DEX implants. Patients were divided into two different subgroups: patients who received DEX implant injections only (group 1) and those who received DEX implants first and then were switched to anti-VEGF agents (group 2). Primary endpoints were changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline to month 6 and month 36. Secondary endpoints included changes in both BCVA and CRT after each DEX implant and adverse events, particularly cataract extraction and elevated intraocular pressure (IOP).

Sixty-six patients with a median [IQR (interquartile ratio)] age of 72 [65.0; 81.1] years were included (40.9% BRVO, 59.1% CRVO), who received a median of 5.0 [min, 1.0; max, 10.0] DEX implants over 3 years. Median [IQR] time to retreatment was 4.8 [4.2; 6.0] months. The median [IQR] improvements in BCVA from baseline until months 6 and 36 were respectively + 10.0 [0; + 20.0] letters (P = 0.040) and + 10.0 [− 8.7; + 20.0] letters (P = 0.364) in the whole population. In group 1, the results were similar, whereas in group 2, BCVA significantly increased at M36 compared with baseline (P = 0.003). The median [IQR] CRT reductions from baseline to months 6 and 36 were respectively − 227.5 [− 337.0; − 52.7] μm and − 224.0 [− 405.0; − 83.8] μm (P < 0.001) in the whole population. Results were similar in both groups. The most common adverse events were cataract extraction (70.4%) and elevated IOP (54.5%). No other serious local complications were observed. Treatment was switched to anti-VEGF agents in 16 (24.2%) patients.

DEX implants are an effective treatment for BRVO and CRVO-associated ME over 3 years. It is a valid treatment even though complications remain frequent. However, functional efficacy seems to decrease with time and repeated injections.