A cornea transplant involves the grafting of a donor cornea into a recipient's anterior eye. The sutures to hold the graft in place must stay in place for a long period of time because the cornea is slow to heal. Explain why the healing process is so slow.

The cornea of an eye is avascular

Explanation:

The healing process in case of a cornea transplant is slow, because the cornea is of an eye is avascular, i. e., it does not contain blood vessels and in the absence of the blood vessels in the cornea tissue the nutrients and oxygen is not able to get delivered there.

Thus the immune system, without the blood vessels in the cornea is weak and hence healing takes time in case of cornea transplant.