What is cornea?
It is the clear eye tissue, first layer, exposing to outside environment. Its refractive clarity and correct shape are responsible for 75% of vision focusing power. Its role is also to protect eyes from infection and injuries.
What are the sources of corneal tissues?
Limbal stem cells in the conjunctiva area replenish corneal epithelium and stroma. Keratocytes, live cells in stroma, maintain long-term strength and clarity of the cornea by providing collagen fibrin in correct patterns. The arranged patterns, spacing, and size of collagen fibers and the amount of water in stroma are critical for corneal clarity.
Corneal endothelium, on the other hand, are not self-renewal. It is thought to derive from neural crest during eye formation. The supply of corneal endothelial cells stops by the age of two. Subsequent growth of corneal endothelial sheath is achieved by enlargement of cell sizes.
Corneal endothelial damages upon diseased or traumatic conditions are not restored by the body. Dysfunctional corneal endothelium causes excessive fluids in corneal stroma; thus, result in corneal opacity and blindness.