Corneal neovascularization is a pathological condition where blood vessels grow inward into the cornea. There are two types of neovascularization - surface neovascularization and deep neovascularization. Surface neovascularization means that blood vessels grow from the conjunctiva into the cornea. With deep neovascularization, the blood vessels do not grow into the cornea. It is caused by an insufficient supply of oxygen.