Repeated DMEK after Long-Standing DALK Failure in Keratoconus: Case Report of a Complex Staged Corneal Transplantation.

Abstract

Background: Deep anterior lamellar keratoplasty (DALK) is the preferred surgical treatment for advanced keratoconus with preserved endothelial function, providing improved graft longevity and reduced endothelial rejection risk compared with penetrating keratoplasty. However, endothelial decompensation may still occur over time, requiring secondary endothelial transplantation with Descemet membrane endothelial keratoplasty (DMEK).
Case Presentation: A 57-year-old Afro-Caribbean woman with keratoconus diagnosed at 40 years of age underwent primary left-sided DALK in 2010 with good visual outcomes for approximately 10 years. Her ocular history was also significant for bilateral cataract surgery with pseudophakia. Due to progressive corneal disease, repeat left DALK was performed in January 2022. Subsequent posterior lamellar opacity and endothelial dysfunction necessitated left DMEK in January 2025. This procedure was complicated intraoperatively, requiring graft removal and ocular surface revision, with repeat endothelial transplantation deferred after temporary corneal clearing was observed. Persistent endothelial failure led to a further DMEK in February 2026; however, anterior segment optical coherence tomography (AS-OCT) demonstrated extensive graft detachment with failure of attachment. A repeat DMEK was therefore performed in March 2026 and required postoperative rebubbling one week later to achieve successful graft reattachment. Following the final procedure, visual acuity in the left eye improved to 6/9 with pinhole correction, with stable intraocular pressure and ongoing topical dexamethasone therapy.
Conclusion: This case demonstrates the evolving paradigm of compartment-specific corneal transplantation in which sequential lamellar procedures are tailored to the affected corneal layer. While DALK effectively treats anterior stromal pathology in keratoconus, long-term endothelial failure may still occur and require endothelial keratoplasty. Repeated DMEK following failed DALK and previous endothelial graft failure represents a complex but feasible staged surgical strategy capable of achieving favourable anatomical and visual outcomes.