Anatomical and Functional Outcomes of Allogeneic Internal Limiting Membrane Transplantation for Refractory Full-Thickness Macular Holes

PURPOSE: To evaluate the anatomical, functional, and outer retinal structural outcomes of allogeneic internal limiting membrane (ILM) transplantation for the treatment of refractory full-thickness macular holes (MH) in eyes where autologous ILM is unavailable due to prior surgery. METHODS: This retrospective case series included 13 eyes of 13 patients. All surgeries were performed using a standard pars plana vitrectomy (PPV) under retrobulbar anesthesia. Allogeneic ILM grafts harvested from donor eyes were stored in Eusol-C at 4-8°C and transplanted under perfluorocarbon liquid using a bimanual forceps-assisted technique. When required, additional ILM tissue was inserted for complete defect filling, and the graft was stabilized with a dispersive viscoelastic agent under air. No postoperative head positioning was prescribed. Pre- and postoperative MH size, best-corrected visual acuity (BCVA), closure rate, and closure morphology were analyzed. RESULTS: Anatomical closure was achieved in all eyes (100%), with primary closure in 12 eyes (92.3%) and successful closure after reoperation in one eye (7.7%). W-type closure was most frequent (61.5%), followed by V-type (30.8%) and U-type (7.7%). BCVA improved significantly from 20/200 (logMAR 1.00) to 20/66 (logMAR 0.52) at final follow-up, corresponding to a median gain of approximately 5 ETDRS lines (p<0.001), whereas intraocular pressure showed no significant change (p=0.118). Despite complete anatomical closure, ellipsoid zone defects persisted in all eyes (100%), and external limiting membrane defects were present in 76.9%, indicating limited outer retinal restoration. CONCLUSION: In this 13-case retrospective series, allogeneic ILM transplantation provided consistent anatomical closure and meaningful visual improvement in refractory macular holes lacking autologous ILM, although restoration of outer retinal microstructure remained limited.