Your cornea is the outermost layer of your eye. It is clear and shaped like a dome. The cornea helps to shield the rest of the eye from germs, dust, and other harmful matter. It also helps your eye to focus. If you wear contact lenses, they float on top of your corneas.
Problems with the cornea include
Treatments of corneal disorders include medicines, corneal transplantation, and corneal laser surgery.
NIH National Eye Institute