Corneal Facts - The Corneal is the clear portion at the front of the eye, and is the first thing that light is refracted off of and therefore the most important refracting component of the eye.  It happens to be a very tough and unique tissue.  It has no blood vessels and is optically clear.  It heals differently than most of the body.  The surface cells rapidly divide and replenish themselves correcting quickly for corneal abrasions or damage.  The inner layer of the cornea, called endothelium, does not divide or replenish itself.  The main body of the cornea called stroma, varies in thickness and is mainly composed of nerves and collagen support tissue.  It can heal and replenish itself, but does so slowly.