Here's a breakdown of the limbus's key features:
* Location: It's the transition zone between the cornea and sclera.
* Composition: It's made of different types of cells, including:
* Epithelial cells: These cells cover the surface of the limbus and help to maintain the integrity of the cornea.
* Stem cells: These cells are crucial for corneal regeneration and can differentiate into other cell types.
* Fibroblasts: These cells produce collagen, which provides structural support to the limbus.
* Blood vessels: These vessels supply the limbus with oxygen and nutrients.
* Functions:
* Corneal regeneration: The limbus contains stem cells that are essential for repairing the cornea after injury or disease.
* Maintaining corneal integrity: The epithelial cells at the limbus help to keep the cornea smooth and transparent.
* Barrier function: The limbus acts as a barrier to prevent the entry of foreign objects and bacteria into the eye.
* Supporting eye structures: The limbus provides structural support for the cornea and sclera.
Clinical significance:
* Corneal transplantation: The limbus is a key region in corneal transplantation as it is the source of stem cells that can repopulate the cornea.
* Limbal stem cell deficiency: This condition occurs when the limbal stem cells are damaged or destroyed, leading to corneal scarring and blindness.
* Pterygium: This condition involves a growth of tissue from the conjunctiva (the thin membrane that lines the inside of the eyelids) onto the cornea, often starting at the limbus.
In summary, the limbus is a crucial region of the eye that plays a vital role in corneal health and vision.