Corneal transplantation, or keratoplasty, consists of the replacement of damaged corneal tissue with healthy corneal tissue from a donor, with the aim of restoring transparency and regularity to the cornea, thus allowing the recovery or improvement of visual acuity.
What types of corneal transplants are there?
There are different types of corneal transplants:
Until a few years ago, when a patient suffered from a corneal alteration that required a transplant, the surgical technique used consisted of replacing the entire corneal thickness. This technique is called Penetrating Keratoplasty and is still used in cases where we cannot save any of the patient’s cornea.
Currently, and thanks to advances in microsurgery, we can perform more selective transplants, the so-called lamellar keratoplasties, which allow us to replace only the affected layer of the cornea with a healthy one. Depending on the corneal layers that require replacement, we can indicate an anterior lamellar keratoplasty or a posterior lamellar (or endothelial) keratoplasty.
In general, lamellar techniques are less aggressive procedures, the patient has less risk of rejection and fewer complications. In addition, the postoperative period is usually more comfortable and visual recovery is faster.
When is it necessary?
When we decide to perform a corneal transplant, it is because there is a disease or an irreversible lesion that affects the shape or transparency of the cornea, and that cannot be solved with any other type of treatment.
The cornea may be altered by congenital or acquired opacities, by edemas that alter its transparency, or by deformities or structural alterations (the most frequent is keratoconus).
How is the procedure performed?
Transplant surgery is a major surgery that is performed in the operating room with the necessary sterility measures. It is usually performed on an outpatient basis (although occasionally it may require the patient’s admission), and under local anesthesia, by injecting anesthetic into the periocular space (peribulbar anesthesia with sedation). Exceptionally, general anesthesia may be required.
It requires a few hours of immobilization and postoperative rest according to the ophthalmologist’s indications. It requires treatment with eye drops and, occasionally, general treatment, including immunosuppressive medication. In the vast majority of patients the operated eye is not painful, although discomfort may occur. Visual recovery is progressive and postoperative follow-up is several months.
What risks are involved?
As with any major surgical procedure, unpredictable situations may occur that require special treatment in each case.
The main risks involved in corneal transplantation are choroidal hemorrhage during the operation (a serious but rare complication), postoperative infection and corneal graft rejection.
What happens if corneal rejection occurs?
Graft rejection is an inflammatory episode that can occur over the years, so periodic ophthalmologic check-ups are highly recommended. In most cases, if diagnosed in time, it can be reversed with medical treatment. In some cases it may require reoperation to replace the corneal tissue.
It should be noted that rejection is much less frequent in lamellar transplants than in penetrating or full-thickness keratoplasty.