Five-Year outcomes of the use of the dexamethasone implant in phakic, treatment-naïve patients with diabetic macular edema

Purpose To evaluate the long-term safety and efficacy of the intravitreal dexamethasone implant (DEX-I) as a primary treatment in phakic, treatment-naïve patients with diabetic macular edema (DME) over a five-year period. Methods This retrospective 5-year extension of a prospective cohort included phakic patients with type 2 diabetes receiving pro re nata (PRN) DEX-I as first-line therapy. The primary outcome measure was change in best-corrected visual acuity (BCVA), whereas secondary outcome measures included changes in central subfield macular thickness (CSMT), injection frequency, adverse events, and the need for supplemental/alternate therapy, if any. Results 122/153 patients originally enrolled for the prospective two-year follow-up study completed 5 years of follow-up and were included in the final analysis. At five years, 59.0% of eyes achieved a ≥ 15-letter gain in BCVA, and 41.1% reached 20/40 or better. CSMT reduction was significant and sustained throughout the follow-up( p = 0.013). The mean number of injections over five years was 3.1. Cataract surgery was performed in 54.1% of eyes. Transient ocular hypertension was noted to occur in 20.3% of eyes, with no patient requiring incisional surgery for glaucoma. One patient developed post-injection endophthalmitis that resolved without long-term sequelae. 5.7% of eyes required treatment switch to anti-VEGF agents. Conclusions In phakic, treatment-naïve patients with DME, long-term treatment with DEX-I is associated with sustained visual and anatomical improvements, a low injection burden, and an acceptable safety profile over 5 years. These findings support its consideration as a primary treatment option in select patient populations with DME.