A Shorter Switching Interval from Intravitreal Dexamethasone Implant to Intravitreal Fluocinolone Acetonide Implant Improves Clinical Outcomes in Diabetic Macular Edema

Background: This study aimed to evaluate whether a shorter switching interval from intravitreal dexamethasone implant (DEXi) to intravitreal fluocinolone acetonide implant (FAci) improves anatomical and functional outcomes in patients with diabetic macular edema. Methods: This was a retrospective, multicenter, observational extension study including 260 eyes, with a mean follow-up of 141.6 ± 55.4 weeks. Results: Prior to FAci injection, 100% of eyes had received DEXi. The mean interval between the last DEXi and the first FAci was 24.2 ± 41.6 weeks (n = 188), i.e., 0–8 weeks in 54 eyes (28.7%) and >8 weeks in 134 eyes (71.3%). Mean BCVA was comparable between patients receiving their last DEXi ≤8 weeks and those receiving it >8 weeks prior to FAci. Compared to baseline, the ≤8-week group consistently and significantly showed lower central macular thickness (CMT) values at months 1–3, 6, 7, 9–11, 14, 16, 19, and 20 (p < 0.05). At months 12 and 24, 90 (34.6%) and 117 (45.0%) eyes required additional treatments, after a median time of 118 weeks (95% CI: 87.7–191.4). In the ≤8-week group, the normalized cumulative incidence of additional treatments was 0.33 treatments per eye at week 52 and 0.72 at week 104, versus 0.66 and 1.38 in the >8-week group, respectively. Intraocular pressure (IOP) elevation incidence did not significantly differ between the ≤8-week and >8-week groups, regardless of the IOP threshold used (≥25, ≥30, or ≥35 mmHg; all p > 0.05). Conclusions: A shorter interval between DEXi and FAci was associated with greater and sustained macular drying, along with a reduced need for additional treatments.