How Does a Corneal Transplant Work?

There are many conditions that can affect the eyes. Some of these can especially impact the cornea, which is the protective clear front surface of the eye that provides most of its light-bending ability.

There are many methods to diagnose and treat corneal disease, but despite these, some advanced conditions eventually require that the cornea be surgically replaced with transplanted tissue from an organ donor. Below is an introduction to when this might be the case and how the cornea transplant process works.

When Is a Corneal Transplant Needed?

The outer layer of the cornea has excellent regenerative capabilities, and this is usually the part of the cornea that is damaged in many conditions. If this is the case, the cornea can easily recover.

However, if damage occurs to the deeper corneal structures, from infection, trauma, complications of previous surgeries, etc., scarring can occur. If this happens and greatly affects vision, a transplant may be required.

The inner corneal layers are responsible for pumping water out of the cornea to keep it of steady thickness and organization. If these layers fail, as is the case in Fuchs’ dystrophy (a hereditary condition) for example, transplantation of just these layers is required to keep the cornea clear and free from swelling.

Another of the most common causes for corneal transplantation is corneal ectasia, or bulging and herniation of the cornea. This can occur after trauma or due to surgical complications, but most commonly is due to keratoconus and similar conditions, which cause thinning and weakening of the corneal layers.

Corneal Transplant Procedures

PKP (penetrating keratoplasty) is a full thickness transplant. In this case, the central part of the cornea is completely removed and replaced with a donor button of corneal tissue then held in place with stitches.

DMEK (Descemet membrane endothelial keratoplasty) and DSEK (Descemet stripping endothelial keratoplasty) are both endothelial transplants, which means they replace the inner corneal layers that are responsible for pumping water out of the cornea back into the rest of the eye. DMEK means that only the very thin layers involved in the disease are replaced.

DSEK is similar to DMEK in that only certain layers of the cornea are replaced rather than the whole thing. DSEK is different in that additional tissue is replaced in addition to only the two inner layers of the cornea that are replaced in DMEK.

Corneal Transplantation Postoperative

After the procedure, various medications will be used to prevent infection and control the inflammation. You will also be asked to rest quite a bit and to not undergo activities which increase the risk of eye injury as the tissue from the recent infection is quite sensitive.

It is also very important to attend all regular follow up appointments and to carefully watch for signs of complication like reduced vision, pain, redness, discharge, etc., both immediately post surgery and all the time afterwards. Graft rejection or failure, infection, etc. can occur though they are rare.

After the transplant is settled, the stitches used to hold it in place might be removed. Vision will usually be much improved, but in some cases special contact lenses will be required to maximize vision over the long term.