Clinical Study on the Treatment of Mixed Component Cornea for High Risk Keratoplasty

Suppression of Graft Rejection Using Mixed Component Cornea in the High-risk Keratoplasty，A Randomized Controlled Trial.

Because of the immunologically privileged nature of the cornea, the graft rejection rate is less than 10% for low-risk keratoplasty. But when the cornea performed 2 or more quadrants of corneal neovascularization after ocular trauma or infection, the graft rejection rate is more than 65%, it is called high-risk keratoplasty.

This study will observe the graft survival of high-risk corneal transplantation using mixed component cornea from different donors.

Ocular trauma or infection lead to corneal limbal stem cell deficiency and central corneal opacification which could only be treated by central penetrating keratoplasty and limbal transplantation, but the rejection rate is very high. In clinical, we found that limbal transplantation combined with central penetrating keratoplasty from different donors can keep the graft transparent for a long time, this result also be found in organ transplantation, multiple donor organ transplantation could reduce rejection risk in liver and kidney transplantation. Therefore, it is speculated that there are different MHC antigens from different donors, which cause different reactions after transplantation. Because there are a large number of Langerhans cells， abundant blood vessels and lymphatic in the limbal, so the rejection occurs early and severely. Continuous and intense limbal rejection leads to the depletion of recipient T cells, lead to the immune tolerance of another donor's central corneal tissue. In this project, central penetrating keratoplasty and limbal transplantation from different donors will be carried out and the graft survival of high-risk corneal transplantation will be observed in clinical, to find a new method for high-risk corneal transplant patients.

Inclusion Criteria:

• Central corneal opacity involving full layer
• Corneal neovascularization in two or more quadrants
• Patients must be willing and able to return for scheduled follow-up examinations for 12 months after surgery
• Ages：18 -70 Years

Exclusion Criteria:

• Central corneal opacity not involving the endothelial layer
• Less than two quadrants of corneal neovascularization
• History of Stevens-Johnson syndrome or Sjogren's syndrome
• Severe eyelid and conjunctival scar
• Loss of vision in contralateral eye
• Pregnant and lactating women