Acellular Bowman Layer and Descemet Membrane Allografts for Non-Ectatic Anterior Corneal Diseases: A Narrative Review of Emerging Evidence.

Penetrating keratoplasty has long been the standard treatment for many corneal pathologies, but interest has grown in less invasive, tissue-sparing alternatives. Bowman's layer (BL) and Descemet's membrane (DM) transplantation are two anterior approaches that use isolated acellular corneal layers to restore structural support and promote epithelial healing, while avoiding many of the limitations of full-thickness grafting. Although both techniques have been described for ectatic disorders, their theoretically low immunogenicity, minimal long-term steroid requirements, and capacity to support reepithelialization make them appropriate options for a range of nonectatic indications. This narrative review describes the application of BL (11 studies) and DM (3 studies) allografts for nonectatic corneal disease, including their surgical techniques, clinical outcomes, and complications. BL allograft studies consisted of 9 case reports (1-3 cases each) and two cohort studies (22 cases and 30 cases), while DM allograft studies included 2 case reports (1 case each) and one large cohort study (99 cases). Across the reviewed literature, both procedures appeared to be associated with complete reepithelialization for the majority of patients, clinically meaningful improvements in visual acuity in patients without visual comorbidities, and few significant complications. Decellularized BL and DM allograft transplantation represent valuable additions to the growing collection of minimally invasive, tissue-sparing approaches for anterior corneal disease, and continued study is warranted to better define their respective roles for nonectatic indications.