Corneal limbus

The corneal limbus is a specialized anatomical transition zone between the transparent cornea and the opaque sclera of the eye. It serves as a critical biological niche for limbal epithelial stem cells (LESCs), which are responsible for the continuous replenishment and maintenance of the corneal epithelium. In health, the limbus acts as a physical and functional barrier that prevents the encroachment of conjunctival tissue and blood vessels onto the clear corneal surface. Dysfunction or damage to this region, a condition known as limbal stem cell deficiency (LSCD), leads to persistent epithelial defects, corneal neovascularization, and eventual loss of vision. From a therapeutic perspective, the limbus is the primary target for regenerative medicine and stem cell therapies, such as Holoclar, which involves the transplantation of cultured limbal stem cells to restore the ocular surface. Additionally, pharmacological agents like cenegermin (rhNGF) target signaling pathways within the limbal environment to promote healing. Emerging drug candidates, such as the peptide BRM424, are specifically designed to stimulate the endogenous proliferation and differentiation of resident limbal stem cells. Because the limbus is an anatomical structure and not a singular molecule or receptor, it is considered a tissue-level target for complex biologics and regenerative pharmacotherapy rather than a classical molecular drug target.

Other names

Corneoscleral limbusLimbal stem cell nicheLimbal regionCorneal limbal niche