Corneal Transplant Surgery Keratoplasty: About the Procedure & Who Is a Candidate

Keratoplasty, or a corneal graft, is an operation that removes all or part of a damaged cornea and replaces it with healthy donor tissue. A successful corneal transplant can reduce pain, restore vision, and improve the appearance of a diseased or damaged cornea.

Who Needs Corneal Transplant Surgery?

Several conditions result in corneal transplant surgery, with keratoconus being one of the most common.

Keratoconus is a condition that occurs when the cornea begins to thin and then gradually bulges outward, resulting in a cone shape instead of the natural spherical appearance of the eye. This causes blurred vision, produces sensitivity to light, and can result in blindness in certain cases. 

Many milder keratoconus cases can be managed with corrective lenses, but certain cases can progress to the point where it is necessary to undergo corneal transplant surgery.

These other conditions may necessitate corneal transplant surgery:

• Problems from other eye procedures
• Enlargement or disfiguration of the cornea
• Deposit formation in the cornea’s middle layer
• Past straining or damage
• Inflammation 

Genetically passed down eye disorders that result in eye pain, discomfort, blurred vision, or vision loss can also contribute to corneal degenerations. However, the most common candidates for a corneal transplant surgery are those with severe cases of keratoconus. 

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Corneal Transplant Types

The right type of transplant will depend on which section of the cornea is damaged or how much of it needs to be replaced. A corneal surgeon will recommend the best transplant option for the specific case. 

• Penetrating keratoplasty (PK): This is a complete transplant of the cornea. Often, the best treatment option for more severe cases of corneal disease or degeneration, PK removes the entire cornea and replaces it with a donor cornea.

• Deep anterior lamellar keratoplasty (DALK): This removes the corneal proper substance (stroma) down to the Descemet’s membrane. DALK is ideal for cases of corneal disease or degeneration that have a functioning endothelium and Descemet’s membrane since both of these are left alone during the procedure. 

• Superficial anterior lamellar keratoplasty (SALK): Related to DALK, this procedure only affects the outside of the cornea and leaves the stroma intact.

• Endothelial keratoplasty (EK): This procedure replaces the inner cell layer of the cornea. When this layer becomes diseased due to an endothelial disorder, EK only removes the affected area and leaves the surrounding healthy areas alone. 

There are two types of endothelial keratoplasty: Descemet stripping EK (DSEK) and Descemet membrane EK (DMEK). They only differ in the amount of donor tissue that is transplanted.

The Corneal Transplant Surgery Procedure

The specifics of the procedure differ according to the type of keratoplasty that is chosen.

PK

Before a penetrating keratoplasty procedure, local or general anesthesia will be administered. 

Then, the surgeon will use a circular cutting device, or trephine, to cut down the donor cornea to the exact size and shape that is required. The surgeon goes on to use a second trephine to remove the portion of the patient’s cornea that is being replaced and then stitch the donor cornea into place. 

DALK or SALK

Local or general anesthetics will also be administered before a deep anterior lamellar keratoplasty or superficial anterior lamellar keratoplasty procedure, but the process does differ a little bit. The corneal surface is incised with a suction trephine and the stromal layers are dissected with a round blade, setting them parallel to Descemet’s membrane. 

During SALK, air is then injected between the stroma and membrane, successfully separating the two layers. The stroma is removed during DALK. The endothelium and the Descemet membrane (and stroma during DALK) are then removed from the donor cornea and the remaining corneal layer is stitched into the recipient’s newly created corneal cavity. 

EK

Although there are two types of EK, the actual procedure is performed the same way. 

After local anesthesia is administered, the surgeon removes the inner cell layer of the cornea. The healthy donor corneal tissue is then implanted through a small incision. An air bubble is then used to unfold the donor tissue against the recipient’s cornea. 

Sometimes, the initial incision can be self-healing. Other times, a suture or two is necessary for full closure. 

Recovery From Keratoplasty

The eye, particularly the cornea, heals incredibly fast in comparison to other bodily tissue. Follow these tips to promote fast and complete healing after surgery:

• Take prescribed medicine. This includes droplets that can be applied directly to the eye. Painkillers may also be prescribed.
• Protect the area of the procedure. Eye patches or protective lenses are essential for proper healing.
• Rest while lying down with your face up. This helps the donor cornea’s tissue to stay intact. Avoid lying on your stomach or side.
• Take extra precaution. Directly after the operation, recipients should avoid rubbing their eyes. They should also stay away from contact sports and abstain from swimming until the cornea is fully healed. 
• Schedule future eye doctor appointments. Regular visits to an eye doctor throughout the year after the procedure are imperative for optimal healing.

Exact recovery time is different for everybody, and it will also depend on the type of surgical transplant. 

A PK procedure takes around a year to fully recover from, seeing as it is a full-thickness transplant. Since just the outer and middle layers are replaced during a DALK/SALK procedure, recovery is much quicker, and patients can be fully healed within 6 to 8 months. Recipients of the EK procedure recover the fastest, with most patients being fully rehabilitated within a couple months or even weeks in some cases. 

Risks & Complications of Corneal Transplant Surgery

Although the risk factor of each type of cornea transplant is low, just like all surgeries, there are risks. 

A small number of keratoplasty procedures can result in glaucoma, ruptured stitches from the procedure, bleeding, and retinal detachment. In some cases, the body can also reject the new donor cornea.

Most of the potential risks have easily identifiable symptoms and can be self-assessed, but rejection isn’t as detectable or obvious. A cornea rejection happens when the donor cornea is mistakenly attacked by the body’s immune defenses. 

Signs of cornea rejection include irritation, discoloration, aching or discomfort, photophobia, and, in extreme cases, temporary blindness. These cases are rare, and about 90 percent of recipients do not experience rejection.

Keratoplasty Results

Initially after a keratoplasty procedure, a patient’s vision might be blurry while the eye adjusts to the new cornea. However, most people who receive a cornea transplant experience improved vision and heal well over the course of a few months. In some cases, full recovery can take a little over a year.

Artificial Corneas & Biosynthetic Corneas

Traditional cornea transplants might not be the right option for some people. In certain cases, artificial corneas can replace the damaged cornea through a surgical procedure known as keratoprosthesis. More and more surgeons are recommending keratoprosthesis to restore vision in these instances. 

Research shows that utilizing artificial corneas is a viable option and can garner good vision results. Although artificial corneas are constructed with plastic, the latest biosynthetic corneas are made with biomaterials that are enhanced with corneal cells. This can result in regenerating and repairing damaged eye tissue. 

Biosynthetic alternatives are continually being improved. They offer opportunities to restore vision in people who do not have donors. 

Keratoplasty FAQs

Is corneal transplant surgery painful? 

The procedure itself is not painful due to the general or local anesthetics. However, people may experience discomfort for a few days following the surgery.

How long does it take to recover from keratoplasty? 

It can take up to a year to fully recover, but most people return to their normal routines within two weeks.

How much time does a corneal transplant surgery take? 

This can depend on the procedure, but most surgeries take less than an hour.

Will stitches be required after a corneal transplant? 

Most people will have stitches, but they are unnoticeable. Some stitches are removed around a month after surgery, while others can remain for years.

When can you drive after a corneal transplant? 

It is sometimes recommended not to drive for several days after a corneal transplant. However, most people can drive once the anesthetic completely wears off, which is around 24 hours.

References

1. Cornea Transplant Overview. (July 2021). National Health Service.

2. Trends in Corneal Transplantation in Keratoconus. (February 2017). Cornea.

3. Updates on Managements for Keratoconus. (June 2018). Journal of Current Ophthalmology.

4. Deep Anterior Lamellar Keratoplasty: Indications, Surgical Techniques and Complications. (January–March 2010). Middle East African Journal of Ophthalmology.

5. Lamellar Keratoplasty Techniques. (September 2018). Indian Journal of Ophthalmology.

6. Endothelial Keratoplasty Update 2020. (May 2021). The Journal of Cornea and External Disease.

7. Endothelial Keratoplasty. (June 2019). BlueCross BlueShield of North Carolina.

8. Artificial Cornea. Cornea Research Foundation of America.

9. Corneal Transplantation in the Modern Era. (July 2019). Indian Journal of Medical Research.

10. Wounding the Cornea to Learn How It Heals. (April 2014). Experimental Eye Research.

11. Risk of Corneal Graft Rejection After High-Risk Keratoplasty Following Fine-Needle Vessel Coagulation of Corneal Neovascularization Combined With Bevacizumab: A Pilot Study. (April 2019). Transplantation Direct.

12. Keratoprosthesis: Current Global Scenario and a Broad Indian Perspective. (May 2018). Indian Journal of Ophthalmology.

13. Update on Suture Techniques in Corneal Transplantation: A Systematic Review. (February 2022). Journal of Clinical Medicine.

14. Understanding Photophobia. (2017). Penn Medicine Department of Ophthalmology.

15. About Corneal Transplantation. (September 2021). American Academy of Ophthalmology.