Twelve‑Month Response and Safety of Intravitreal Dexamethasone Implant in Treatment‑Naïve and Recalcitrant Diabetic Macular Edema (TREAT-DME Study)

Somnath Chakraborty,1 Jay U Sheth,2 Santanu Ganguly,1 Rahul Reddy1 1Department of Retina Services, Retina Institute of Bengal, Siliguri, India; 2Department of Retina Services, Shantilal Shanghvi Eye Institute, Mumbai, IndiaCorrespondence: Somnath Chakraborty, Department of Retina Services, Retina Institute of Bengal, C/O Reddy Health Care 3 rd Floor Uttarapan Market Complex, Hill Cart Road, Pradhan Nagar, Siliguri, West Bengal, 734003, India, Tel +91-9002508334, Email [email protected]: To compare twelve-month visual, anatomical, safety, and inflammation-biomarker outcomes of intravitreal dexamethasone implant (DEX) in treatment-naïve versus recalcitrant center-involving diabetic macular edema (CI-DME) eyes.Patients and Methods: In this multicenter, retrospective cohort study (January 2022 to December 2024) at two Indian tertiary centers, adults with type 2 diabetes and CI-DME confirmed by optical coherence tomography (OCT) were stratified into treatment-naïve or recalcitrant cohorts. All eyes received a 0.7 mg dexamethasone implant, with pro-re-nata retreatment for recurrent fluid, ≥ 5-letter best-corrected visual acuity (BCVA) loss, or ≥ 50 μm central macular thickness (CMT) increase. Visits at baseline and periodic intervals up to 12 months included BCVA, intraocular pressure (IOP), slit-lamp and fundus exams, and OCT quantification of CMT and presence and/or hyperreflective foci (HRF). Safety and adverse event monitoring included IOP elevations, cataract progression, and other ocular adverse events. Statistical analysis used paired and independent tests with P < 0.05.Results: We analyzed 102 eyes (30 naïve, 72 recalcitrant) from 74 patients (mean age 61.7 ± 8.8 years). Mean DEX implants per eye were 1.83 ± 0.73, higher in recalcitrant eyes (1.87 vs 1.73; P = 0.02). At 12 months, mean BCVA improved from 0.73 ± 0.26 to 0.62 ± 0.28 logMAR (P = 0.002), with no intergroup differences (P > 0.05). Mean CMT decreased from 520 ± 144 to 462 ± 192 μm (P = 0.03), similarly across cohorts (P > 0.10). HRF declined from 58% to 26% (P < 0.001). Ocular adverse events included cataract progression in 39% of phakic eyes (26% underwent surgery) and transient IOP elevations > 21 mmHg in 9.8%, all managed medically; no glaucoma surgery was required.Conclusion: In real-world practice, intravitreal DEX implant delivers sustained visual and anatomical benefits in both treatment-naïve and recalcitrant CI-DME eyes. Although cataract progression and transient IOP rises occur, they are predictably manageable. Its extended durability and acceptable safety profile underscore DEX implant as a practical, valuable option across diverse DME populations.Keywords: dexamethasone implant, diabetic macular edema, real-world