Role of stem cells in ocular diseases: Progress and challenges

Ocular diseases, including corneal disease, glaucoma, age-related macular degeneration (AMD), diabetic retinopathy, and retinopathy of prematurity, can significantly impair vision and reduce the quality of life. Due to the fact that degenerated cells in these diseases are unable to regenerate, treatments for them have limited efficacy. Stem cell therapies are revolutionizing the treatment of degenerative eye conditions, enabling tissue and functional recovery through mechanisms such as cell replacement and paracrine signaling. This review examines the advancements in stem cell therapy for ocular diseases, from preclinical studies to early clinical trials, focusing on various types of stem cells, including embryonic stem cells, induced pluripotent stem cells (iPSCs), and mesenchymal stem cells. Significant progress has been made with iPSC-derived retinal pigment epithelium cell transplantation in AMD treatment, showing cell survival in trials as well as with mesenchymal stem cells for corneal repair through anti-inflammatory effects. Challenges remain, such as controlling differentiation to prevent tumorigenesis, managing immune rejection, and ensuring production that complies with Good Manufacturing Practice (GMP) standards. By integrating mechanistic insights with translational strategies, this review outlines pathways to optimize stem cell therapies for previously intractable ocular diseases.