The size and thickness of the corneal scar varies according to the severity of the injury. The thin ones are cloudy and shallow, called corneal clouding, the thick ones involve the deep stromal layer of the cornea called corneal opacity, and the thickest ones involve the whole layer of the cornea called corneal white spots. Second, which conditions can form corneal scar 1, ulcerative scar: including bacterial corneal ulcer, viral corneal ulcer, fungal corneal ulcer. When the corneal ulcer reaches the clean stage, the connective tissue in the cornea proliferates and repairs the defect, the ulcer heals and a scar is formed. If the ulcer is small and shallow and involves only the epithelial cell layer, the cornea can be completely clear again. If the anterior elastic membrane and superficial layers of the corneal parenchyma are involved, a dense, cloudy scar remains. The clouding is initially dark and then increases in concentration, but never crosses the edge of the ulcer. 2, traumatic scar: including angle blunt contusion, perforation injury, explosion injury, etc. A small area of simple epithelial injury can be repaired within 24 hours and will not leave a scar. If the injury is not treated in time, there is often a large amount of fibrin filling in the wound, and the connective tissue proliferates to form a scar. 3, chemical scarring: including acid and alkali burns, when the corneal injury is serious, chemical substances invade the stroma layer, causing corneal scarring caused by protein coagulation and denaturation in the corneal tissue, after a long time, neovascularization appears on the cornea, and the epithelium covering the cornea has the characteristics of the conjunctiva, causing great difficulties for the later treatment. 4, congenital scar: developmental process due to incomplete division or absorption of the mesoderm, ectodermal posterior elastic membrane and endothelial cells lack, while the iris band adhesion to the cornea and formed 5, acute cone corneal perforation to form a scar: cone corneal development to the acute stage, due to acute rupture of the posterior elastic membrane, atrial water into the cornea causing acute edema and clouding of the stroma and epithelium, severe anterior elastic membrane rupture, and for In severe cases, the anterior elastic membrane ruptures and is replaced by fibrous tissue to form a scar, which increases the difficulty of later treatment. The consequences of corneal scarring and the treatment of corneal scarring are mainly two: 1, affect the aesthetics: scarring on the cornea, and the other eye is not consistent, this is particularly important for young people, you can achieve cosmetic effects through corneal transplantation. 2, affect vision: scar on the cornea, especially in the visual axis, like a watch on the table door blocking something, will affect the clarity of objects on the retina, see things naturally can not see, can be cut off through corneal transplantation surgery, replaced by a transparent cornea to increase vision.