Cornea Transplant Surgery (Keratoplasty)
Keratoplasty, i.e. cornea transplant surgery is the most frequently performed transplant surgery in the world. The goal of the procedure is to establish a complete clarity and suitable curvature of the cornea, as well as to enable better visual acuity.
This kind of surgery is performed with patients whose cornea is cloudy due to former eye surgery, inflammation, infection, or eye damage. More precisely, these are the indications for keratoplasty: chronic swelling of the cornea after the cataract surgery, leukoma (the corneal scar that endangers the visual acuity), or corneal dystrophies, including advanced keratoconus.
On the one hand, the success of the transplant surgery depends on the disease treated with this surgery, and on the other hand, it depends on the donor graft tissue, i.e. on its quality and the way it is transplanted.
Types of Corneal Transplant
Penetrating keratoplasty is performed when all the layers of the cornea are damaged due to scarring or bulging which last for several months. Therefore, their surgical treatment is done by transplanting the corneal tissue of the donor with all its layers into the opening created in the center of the cornea by cutting all its layers.
This technique can be used for other surgeries as well, regardless of whether they reach all the layers or only some of them (dystrophies, including keratoconus).
The partial-thickness corneal transplant was introduced as a novelty 15 years ago. Its goal is to transplant only the diseased layers of the cornea instead of all of them wherever possible. This is an ideal way to avoid or decrease some of the complications arising from penetrating keratoplasty such as long recovery, high and irregular astigmatism, or rejection (an immune reaction) of some layers.
The surgery is performed in the following way: as with the cataract surgery, the doctor removes the damaged endothelium (the damaged layer of the cornea) through a small opening at the edge of the cornea. On its place, he puts a healthy layer whose cells will pump out the extra liquid and clear the cornea. This technique is called DSEK or DMEK. With it there is neither a big cut nor many stitches, if any, recovery is quicker, astigmatism is low, and the possibility of rejection is decreased.
In another case, with progressive keratoconus, where it is neither possible to correct the vision with contact lenses nor to stop its progression with ultraviolet radiation of the cornea soaked in vitamin B2, we apply the technique of selective transplant surgery – DALK. Here, the patient’s cornea is separated into layers at its bottom, with special attention to keep the healthy, vital inner layer undamaged. Then the doctor removes a part of the cornea and inserts the donor graft tissue of the same radius and thickness, and sews it with an imperceptible surgical suture.
The benefits of this method are a few: there is no opening of the eyeball and no possibility to insert an infection into it. Also, there is no deterioration of the endothelium inserted into the eye and no immune reaction in the layer.
Postoperative Follow-up
Since the transplant surgery is a surgical intervention with biological changes caused by insertion of foreign tissue, each of the cornea transplant methods has a possibility for complications throughout the operation, immediately after it, or in the postoperative period lasting several months.
In the first days after the surgery, the vision is blurred and the eye is sensitive to light. The doctor prescribes the patient a specific treatment with eye drops, to prevent the rejection of the transplant. Since the transplant reaction usually occurs in the first year after the surgery (although it can also occur later), regular follow-ups are necessary for certain time intervals for postoperative monitoring. Over time, the possibility of complications and their severity decrease, and the possibility to treat them successfully increases.