Intravitreal Dexamethasone Implant in Anti-Vascular Endothelial Growth Factor Pretreated Diabetic Macular Edema-A Swiss Cohort Study

Background/Objectives: Diabetic macular edema (DME) is a significant cause of visual impairment, often treated with anti-vascular endothelial growth factor (anti-VEGF) agents. However, some patients do not respond adequately to this treatment. This study aims to evaluate the contribution of the intravitreal dexamethasone (DEX) implant as a second-line treatment in DME patients with insufficient response to anti-VEGF therapy or with high treatment burden. Methods: This retrospective multicenter cohort study was conducted across seven clinical sites in Switzerland. The study included eyes with active DME that had been pretreated with anti-VEGF for at least six months before receiving DEX therapy. Data were extracted from electronic patient records, focusing on best-corrected visual acuity (BCVA), central subfield thickness (CST), and injection frequency. Results: A total of 95 eyes from 89 patients (38.8% females, mean age 65.6 +/- 9.1 years, follow-up time 80.6 +/- 38.5 [13.5-166.7] months) were analyzed. Prior to the first DEX implant, eyes had undergone an average of 16.0 +/- 13.3 anti-VEGF injections over 32.5 +/- 22.4 months. Post-DEX treatment, 22.1% of eyes received DEX monotherapy, 44.2% received a combination of DEX and anti-VEGF, 25.3% continued with anti-VEGF monotherapy, and 8.4% received no further treatment. The number of anti-VEGF injections decreased significantly from 6.4 +/- 3.1 in the year before DEX to 1.6 +/- 2.4 in the year after DEX (p < 0.001). BCVA remained stable (0.4 +/- 0.3 logMAR at baseline, 0.4 +/- 0.5 logMAR at 24 months, p = 0.2), while CST improved from 477.7 +/- 141.0 to 320.4 +/- 125.5 mu m (p < 0.001), and the presence of retinal fluid decreased from 98.0% to 61.1% (p = 0.021). During follow-up, 26.3% of eyes required glaucoma medication, 4.2% underwent glaucoma surgery, and 1.1% needed cataract surgery. Conclusions: In real-world clinical settings, the addition of DEX to anti-VEGF therapy in DME patients significantly reduces treatment burden and retinal fluid while maintaining visual function. Treatment decisions should balance anatomical and functional outcomes, considering individual patient needs.