The prevention and treatment of rejection of corneal transplantation is based on both prevention and treatment. Rejection after corneal transplantation is generally unlikely to occur within 2 weeks and rarely occurs within 1-2 months after surgery with adequate amounts of corticosteroids. The peak time of rejection is 4-18 months after surgery, and the incidence decreases gradually afterwards. Rejection is often induced by stitch removal, corticosteroid reduction and cold, and the main symptoms are vision loss. The main symptoms are loss of vision, bloodshot eyes, photophobia and tearing, and clouding of the corneal graft. If you have any of these symptoms, you should immediately visit our keratoconus specialist for follow-up. For the treatment of rejection after corneal transplantation, the main clinical measures are: 1, the application of corticosteroids: this is the most important drug for the treatment of rejection, in the application process should adhere to the principle of adequate, regular and slow discontinuation, after the rejection reaction to increase the amount of medication, local attention should be paid to the possible complications such as increased intraocular pressure. 2, the application of cyclosporine A: is an effective immunosuppressant, local routine use; systemic use generally in the glucocorticoid treatment is ineffective or with glucocorticoid use. 3, if rejection has occurred and the treatment is ineffective and the graft piece is cloudy, consider performing corneal transplantation again.