Feature developments in artificial corneal devices: a review

Corneal disease ranks as the fifth leading cause of global blindness, affecting more than 10 million individuals. Donor corneal transplantation, keratoplasty, remains the mainstay of addressing loss of corneal clarity. Historically, full-thickness penetrating keratoplasty (PK) has been one of the most successful and widely performed transplant procedures, although predominantly available in developed countries. The landscape for corneal transplantation has changed dramatically over the last two decades with the emergence of partial-thickness transplantation techniques and corneal cross-linking, which provide less invasive means of treating diseases like Fuchs' dystrophy and keratoconus, respectively. Currently, PK is often performed in eyes with complex problems and at high risk of graft failure. In fact, repeat grafting has become the second most common indication for PK. Furthermore, a significant shortage of donor corneas persists, with half of the global population lacking access to tissues. This shortage is particularly pronounced in developing countries, which lack the necessary infrastructure to support corneal transplantation despite bearing the highest burden of corneal blindness. Artificial corneal devices, known as keratoprostheses, have been posited as a remedy for various constraints of conventional keratoplasty and have demonstrated promising outcomes, particularly in high-risk cases. Synthetic devices are not subject to the risk of allograft rejection or endothelial failure. In resource-limited areas, keratoprostheses could potentially replace donor keratoplasty by eliminating the costly eye banking system to access, preserve and distribute the short-lived fresh donor tissues. Herein, we report the design, surgical technique, indications and early outcomes of clinical-stage fully synthetic keratoprostheses currently undergoing trials globally.