The cornea is the oval-like, black-looking, actually transparent tissue located at the very front of the eye. Cornea is an important part of the structure of the eye, located in the first 1/6 of the eyeball, similar to the oval-shaped transparent tissue, the cornea has no blood vessels, in a relatively immune amnesty status. The cornea is divided into five layers from front to back, i.e., corneal epithelium, anterior corneal elastic layer, corneal stroma, posterior corneal elastic layer, and corneal endothelial cell layer. The cornea is an important refractive system with a refractive power of about 43D. The cornea is susceptible to invasion by harmful external factors, which can lead to keratitis and corneal ulcers, which require prompt consultation and treatment to avoid causing corneal scarring and affecting vision.