The Development, Growth, and Regeneration of the Crystalline Lens: A Review

Purpose: This review aims to provide an understanding of the history of research on, the biological processes governing the different forms of, and an overview of more recent work on lens regeneration as they will likely prove vital in bringing the study of lens regeneration into the clinic.Methods: A review of the literature on lens regeneration research was conducted.Results: Lens regeneration is characterized by the regrowth or repair of the lens following the removal of either a portion or of the entire lens. A brief history of research on lens regeneration is provided, from the discovery in early antiquity of the ability of some animals to regenerate lost tissue, to the systematic cataloguing of the mechanisms of lens regeneration in the 19th century, until the more modern unraveling of the genetic and biochemical processes governing lens regeneration. The anatomy and physiology of the lens as well as the mechanisms by which the lens develops inform its regenerative capabilities by determining the processes that must occur in order to regrow a new lens or repair a damaged one. Lens regeneration occurs by one of several species-dependent methods: some amphibians can regrow a new lens after complete removal of the old one while some mammals can only repair a damaged lens. This review provides an overview of the mechanisms controlling the different types of lens regeneration.Conclusion: The development and growth of the intact lens influence the mechanisms that govern lens regeneration. Recent advances in the field have begun to apply concepts of the field in the clinic and have made significant progress towards realizing the goal of using lens regeneration to repair a damaged lens in the clinic.