Corneal transplantation is the replacement of cloudy or diseased corneal tissue with allogeneic normal clear corneal tissue to restore sight or control corneal disease in the affected eye, which has the highest success rate among allogeneic transplants and is one of the most important sight restoration procedures in ophthalmology. With the rapid development of new technologies and equipment in the past 20 years, the development of various specialties in ophthalmology has been promoted, and corneal transplantation has also been actively developed. Along with the application of viscoelastic, diamond knife, ultrasonic corneal thickness gauge, artificial anterior chamber, lamellar keratome and excimer laser, this procedure has become safer and more accurate, and has broken through its traditional application to become a means of optical rehabilitation. 1, penetrating keratoplasty penetrating keratoplasty refers to the whole layer of corneal transplantation including the endothelium, the scope of its indications has been significantly expanded in recent years. 1950s, the indications for this procedure are mainly the corneal scar after single virus keratitis, rarely involved in large vesicular lesions. 80s onwards, the indications for this procedure are mainly the retransplantation of the hyperplastic layer, due to corneal, lens removal after large vesicular keratitis lesions. lesions. In recent years, the main indications are infectious keratitis, especially keratoconus after herpes simplex virus keratitis, followed by corneal clouding after ocular trauma, followed by large vesicular keratopathy, cone cornea, corneal dystrophy or corneal degeneration. The requirements and evaluation criteria for successful optical penetration are: (1) Good donor material. (2) Transparent graft. (3) No complications due to surgical errors. (4) Reduction of postoperative corneal refractive abnormalities. Surgical techniques: adequate IOP reduction, eye softening, graft size selection, donor requirements: graft preparation, graft bed preparation, graft suturing, anterior chamber reconstruction. In recent years, the main development of microsurgical techniques for penetrating corneal transplantation is to minimize the prevention and reduction of corneal astigmatism of surgical origin. 2, lamellar keratoplasty (1) anterior lamellar keratoplasty includes optical therapeutic keratomileusis, lamellar keratoplasty, flattened surface keratoplasty, and annular lamellar keratoplasty. Scleral lamellar graft, amniotic membrane graft combined with corneal graft sheet and plastic corneal implant for corneal ulcer and keratolysis. Compared with penetrating keratoplasty, lamellar keratoplasty has the advantage of avoiding the complications of “open” surgery, such as early suture removal, wound tearing, and high rejection rate, but the presence of lamellar clouding after lamellar keratoplasty often affects the corrected visual acuity after surgery. In order to reduce this cloudiness, deep and consistent air separation, viscoelastic separation and optical posterior lamellar cutting should be used to create a smooth and consistent implant bed and to remove the diseased tissue adequately. (2) Posterior lamellar keratoplasty for corneal endothelial cell lesions, the posterior cornea mainly includes large vesicular keratopathy and corneal dystrophy, and the current treatment for this disease is mainly penetrating keratoplasty. It has been reported that penetrating corneal transplantation for posterior corneal ulcers has a 5-year postoperative corneal transparency rate of 60%-90%. However, the presence of high or irregular postoperative astigmatism, poor wound closure, and suture-related complications have led to efforts to find a more optimal approach to corneal transplantation. These complications can theoretically be reduced by simply replacing the diseased posterior lamina tissue, which was first used clinically by Barr aqner et al. in the 1980s and is now widely used in China. 3, therapeutic corneal transplantation Therapeutic corneal transplantation is actually an extension of the indications for optical corneal transplantation, which refers to the treatment of various corneal inflammation, perforated lesions, trauma and tumors, in order to save the eye from destruction and preserve the main purpose of the eye chamber function. At present, for some severe infectious keratitis, drug treatment is ineffective, the disease cannot be controlled, the inflammation is recurrent or persistent, resulting in posterior corneal elastosis, on the verge of perforation or perforation, most of the cases were treated by conservative lamellar dressing or conjunctival flap covering, some cases finally formed adhesive corneal white spots or corneal fistula, secondary glaucoma, ocular atrophy, the majority of cases treated by corneal transplantation The majority of cases treated with corneal transplantation shortened the healing time and saved the eyes with varying degrees of visual acuity, fully demonstrating the value of the use of therapeutic corneal transplantation.