Corneal stem cells in the eye clinic.

INTRODUCTION OR
BACKGROUND: Corneal opacity is a common cause of blindness. The majority of cases result from ulceration and scarring following infection or trauma, but in a proportion corneal epithelial stem cell (SC) deficiency leads to an inability to maintain a healthy corneal surface. SOURCES OF DATA: This review includes systematic reviews and individual case series of treatments for corneal epithelial SC deficiency. AREAS OF AGREEMENT: Two techniques such as transplantation of large segments of cornea from a healthy eye and ex vivo expansion of corneal SCs in the laboratory were compared. Both have merits and their clinical outcomes are similar. The smaller biopsy in the cell expansion approach has less risk for the donor eye, which is a significant advantage. AREAS OF CONTROVERSY: Treatment algorithms for different aetiologies of SC failure are evolving. The proportion of true corneal epithelial SCs in ex vivo culture is unclear and it is unknown whether these cells survive long term. GROWING POINTS: In this study, the optimum method of cell culture and transplantation is being intensively investigated. AREAS TIMELY FOR DEVELOPING RESEARCH: Development of tissues using multiple cell types, genetic modification to treat hereditary corneal disorders and development of cell therapy for other eye diseases are future possibilities.