Long-Term Control of Retinal Thickness Variability and Vision Following the 0.19 mg Fluocinolone Acetonide Implant

Purpose: To assess the impact of retinal thickness variability (RTV) control on visual and treatment burden outcomes in patients with diabetic macular edema (DME) who received the 0.19 mg fluocinolone acetonide (FAc) intravitreal implant (Iluvien, Alimera Sciences). Methods: This post hoc analysis examined the outcomes of a 3-year, phase 4, nonrandomized, open-label observational study. Retinal thickness was measured as central subfield thickness (CST). RTV was quantified by CST area under the curve (CST-AUC), retinal thickness amplitude (RTA), and retinal thickness standard deviation (RTSD). Visual outcomes were measured as best-corrected visual acuity (BCVA), and treatment burden was measured as the number of yearly supplemental DME treatments. Results: The percentage of eyes with a CST ≤300 µm fluctuated throughout the study but was significantly increased relative to baseline at 36 months (baseline: 32.9% vs 36 months: 46.8%; P < .05). FAc significantly reduced RTV in all measures more than 36 months (P < .0001). When divided into quartiles, eyes with the best RTV control post FAc had the greatest BCVA gains and improved disease control (ie, reduced need for supplemental therapy). The last-observed BCVA letter score exhibited linear correlations with CST-AUC (R² = -0.100), RTA (R² = -0.125), and RTSD (R² = -0.162). A multivariate linear regression with baseline BCVA as a covariate displayed improved correlations with the last-observed BCVA, CST-AUC (R² = -0.448), RTA (R² = -0.432), and RTSD (R² = -0.436). Conclusions: The sustained corticosteroid release of the 0.19 mg FAc implant reduced RTV in patients with DME, which directly correlated with significantly improved vision and a reduced supplemental treatment burden.