بنية القرنية cornea

The cornea is a clear because it has a highly organized structure of
collagen fibrils, it is free of blood vessels and allows the passage of
light in an organized way so a clear image may be focused on the
retina. The corneal layers all contribute to its function. The endothelial
cells actively pump out fluid from the stroma. A healthy
tear film (with all its constituent layers) and eyelids are vital to
maintain corneal integrity and clarity.
Disturbance of the eyelids, conjunctiva or tear film may lead to
corneal problems including ulceration. If the disease is severe,
corneal scarring with vascularization may lead to reduced vision
and in rare cases to corneal perforation requiring surgical
management. Corneal anaesthesia (Vth nerve palsy) predisposes
to severe keratitis