Corneal Transplant (Artificial & Conventional)

What is a corneal transplant?

A corneal transplant, or keratoplasty, is a surgical procedure that replaces a cloudy or scarred cornea with a clear donor cornea to improve vision.

When the cornea becomes cloudy due to disease or injury, light rays are unable to pass through to reach the retina (the light-sensitive part of the eye). This can lead to poor vision or blindness. The cornea can be damaged by:

• Corneal injuries
• Infections or diseases
• Age-related degeneration

Types of corneal transplant surgery

In general, corneal transplant surgery can be classified into:

• Descemet's Stripping Endothelial Keratoplasty (DSEK). A procedure that removes diseased endothelial cells from the inside of the cornea and replaces them with a new layer of endothelial cells.
• Lamellar keratoplasty. A more advanced procedure that replaces diseased parts of the cornea and does not affect healthy corneal tissue. It is also known as a partial corneal transplant.
• Penetrating keratoplasty. Generally regarded as conventional corneal transplant surgery, this procedure replaces the entire cornea.
• Artificial cornea transplant (keratoprosthesis). This procedure replaces a diseased or scarred cornea with an artificial cornea made of plastic polymers.

Your surgeon will advise the most suitable procedure based on your condition and clinical findings.

Donor corneas

In Singapore, donor corneas are procured:

• Locally through cornea donation programmes (e.g. by the Singapore Eye Bank)
• Internationally from accredited eye banks (e.g. from countries such as Sri Lanka, the United States and the Philippines)

Why do you need a corneal transplant?

If you have poor vision due to a diseased or cloudy cornea but have a healthy nerve and retina at the back of your eye, a corneal transplant can help to restore your vision.

As the damaged cornea can look cloudy, replacement with a clear donor cornea can also be a cosmetic improvement.

A corneal transplant can treat conditions such as:

• Swelling of the cornea
• Thinning or rupture of the cornea
• Fuchs' dystrophy, a hereditary condition
• A cornea that bulges outward (keratoconus)
• Cornea scarring, caused by infection or injury
• Corneal ulcers not responding to medical treatment
• Complications caused by previous eye surgery

What are the risks and complications of a corneal transplant?

A corneal transplant is relatively safe. However, it carries a small risk of complications, such as:

• Bleeding
• Eye infection
• Pressure increase within the eyeball (glaucoma)
• Problems with the stitches used to secure the donor cornea
• Retinal problems, such as retinal detachment or swelling
• Rejection of the donor cornea

Symptoms of corneal transplant rejection

Cornea rejection – when your immune system attacks the donor cornea – occurs in about 10% of cornea transplants. Visit your ophthalmologist immediately if you experience:

• Light sensitivity
• Eye pain and reddening
• Vision loss or impairment

How do you prepare for a corneal transplant?

Before your surgery, you will undergo:

• A thorough eye exam to eliminate possible conditions that might cause complications.
• Eye measurements to determine the size of your donor cornea.
• A review of all medications and supplements you're taking that might affect your surgery.
• Treatment for conditions such as infections or inflammation that may affect your corneal transplant.

What can you expect in a corneal transplant?

Depending on your condition, your eye surgeon will decide which method of corneal transplant surgery is best for you and what to expect during the procedure.

Estimated duration

The amount of time spent in surgery will vary depending on your individual condition.

During the procedure

Your surgeon may administer any of the following:

• A sedative to help you relax
• Local anaesthetic to numb your eye
• General anaesthesia to put you to sleep

Surgery will be done on one eye at a time.

After the procedure

You can expect to:

• Wear eye protection such as eye shields or glasses to aid in the recovery process.
• Receive medication such as eye drops to help control infection, swelling and pain as well as suppress the immune system to prevent cornea rejection.
• Remove your eye protection the day after your procedure. Once you remove your eye protection, your sight may become blurred. This is normal.

Care and recovery after a corneal transplant

Depending on your procedure, your corneal transplant recovery time can vary from a few weeks to a year.

To help you care for your new cornea and support your recovery, your doctor may advise you to:

• Avoid rubbing or pressing on your eye.
• Avoid exertion and unnecessary movement, while working to slowly resume normal activities including exercise.
• Return for regular follow-ups to monitor progress and possible complications.
• Lay on your back after surgery to help the new tissue stay in place.
• Take extra precautions to avoid any future eye injury.