The cornea is the clear, outer layer of the eye. A corneal transplant is usually recommended when vision due to cornea changes can no longer be improved with medical treatment or corrective lenses. Eye diseases and conditions that may necessitate a corneal transplant include keratoconus, Fuch’s dystrophy, ocular herpes infections, chemical burns and trauma. Also, since the corneal contains nerve endings, a transplant may be necessary to alleviate extreme pain caused by trauma or disease.
A full-thickness corneal transplant, which is also known as penetrating keratoplasty (PKP), is a surgical procedure in which the entire damaged cornea is replaced by a donor cornea from an eye bank. During the operation, a round portion of the damaged cornea is removed and replaced with a round portion of the donor cornea. The donor cornea is sutured into place with very thin nylon thread. These sutures will remain in place several months during the healing process. Antibiotic drops and steroid drops are used post-operatively and long-term use of steroid drops may be necessary to prevent rejection of the new corneal tissue. Since the cornea normally does not contain blood vessels, the rejection rate of the donor cornea is very low, between 5% and 30%, compared to other transplant surgeries. However, a corneal transplant will require dozens of follow-up visits with your surgeon, the healing process is quite lengthy, and post-operative vision is rarely regarded as perfect.
In the past decade, partial-thickness corneal transplant surgeries called DSEK and DALK have been introduced as alternatives to full-thickness corneal transplant.