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Cornea transplant

A cornea transplant is an operation to remove all or part of a damaged cornea and replace it with healthy donor tissue.

A cornea transplant is often referred to as keratoplasty or a corneal graft.

It can be used to improve sight, relieve pain and treat severe infection or damage.

One of the most common reasons for a cornea transplant is a condition called keratoconus, which causes the cornea to change shape.

What is the cornea and what does it do?

The cornea is the clear outer layer at the front of the eyeball. It acts as a window to the eye.

The coloured iris and the pupil (the black dot in the centre of the iris) can be seen through the cornea.

The cornea helps to focus light rays on to the retina (the light-sensitive film at the back of the eye). This “picture” is then transmitted to the brain.

When the cornea is damaged, it can become less transparent or its shape can change.

This can prevent light reaching the retina and causes the picture transmitted to the brain to be distorted or unclear.

How is a transplant carried out?

The type of cornea transplant you have will depend on which part of the cornea is damaged or how much of the cornea needs replacing.

The options include:

  • penetrating keratoplasty (PK) – a full-thickness transplant
  • deep anterior lamellar keratoplasty (DALK) – replacing or reshaping the outer and middle (front) layers of the cornea
  • endothelial keratoplasty (EK) – replacing the deeper (back) layers of the cornea.

A cornea transplant can be carried out under general anaesthetic (where you’re unconscious) or local anaesthetic (where the area is numbed and you’re awake).

The surgery usually takes less than an hour and, depending on your circumstances, you either leave hospital the same day or stay overnight. 

If surgery involves the transplantation of the outer cornea, the new outer cornea is held in place with stitches, which usually stay in for more than 12 months.

An endothelial transplant (EK) does not require stitches. It’s held in place by an air bubble until a few days later, when it naturally sticks to the deep layer of the cornea.

Are there any risks?

As with all types of surgery, there is a risk of complications resulting from a cornea transplant.

These can include the new cornea being rejected by the body, infection and further vision problems.

Most cornea transplants are successful and will work without complications for at least 10 years.

Post cornea transplant

The recovery time for a cornea transplant depends on the type of transplant you have.

It takes about 18 months to enjoy the final results of a full-thickness transplant, although it’s usually possible to provide glasses or a contact lens much earlier.

Recovery is usually faster after replacing just the outer and middle layers (DALK).

Endothelial transplants (EK) tend to have a faster recovery time of months or even weeks.

It’s important to take good care of your eye to improve your chances of a good recovery.

This means not rubbing your eye and avoiding activities such as contact sports and swimming until you’re told it’s safe.

How it is performed

The type of cornea transplant you’ll be offered will depend on the parts of the cornea that need to be replaced.

Most cornea transplant operations involve transplanting the full thickness of the cornea.

But recent advances in technology mean it’s sometimes possible to only transplant part of the cornea.

Full-thickness transplants

A full-thickness transplant is called a penetrating keratoplasty (PK).

During this procedure, a circular piece of damaged cornea from the centre of your eye is removed and replaced with the donated cornea.

The new cornea is held in place by tiny stitches, which sometimes form a star-like pattern around the edges. You may be able to see the stitches faintly after the operation.

The operation may be done under local anaesthetic or general anaesthetic, and usually takes under 1 hour. 

If local anaesthetic is used, you will not be able to see through the eye during the operation as the anaesthetic temporarily stops the eye working.

Most people have to stay in hospital for a night after a full-thickness cornea transplant.

Partial-thickness transplants

Recently, techniques have been developed that allow only parts of the cornea to be transplanted.

These techniques are not suitable for everyone in need of a cornea transplant and they can take longer to perform, but often have a faster recovery time and a lower risk of complications.

There are several different techniques your surgeon may use, depending on which layers of the cornea are transplanted.

Generally, these techniques can be broken down into transplants involving the front portion of the cornea and those involving the back portion.

Most of these procedures are carried out using cutting instruments, such as a trephine, although lasers are sometimes used.

These procedures can be carried out using either local or general anaesthetic, and you may be able to go home on the same day of the procedure.

Transplanting the front portion of the cornea

The main techniques for transplanting the front parts of the cornea include:

  • anterior lamellar keratoplasty (ALK) – removing and replacing only the outer (front) layers of the cornea
  • deep anterior lamellar keratoplasty (DALK) – removing and replacing the outer and middle layers of the cornea, leaving the inner (back) layers intact

As with a penetrating keratoplasty, stitches are used to fix the donated cornea in place during both of these procedures.

Transplanting the back portion of the cornea

The main techniques for transplanting the back parts of the cornea include:

  • Descemet’s stripping endothelial keratoplasty (DSEK) – replacing the inner lining of the cornea together with about 20% of the corneal supporting tissue (corneal stroma)
  • Descemet’s membrane endothelial keratoplasty (DMEK) – replacing only the inner layer of cells of the cornea

These techniques allow faster visual recovery and have a lower risk of complications.

Stitches are not used during either of these procedures. Instead, the donated tissue is held in place using a temporary air bubble.

Cornea donations

The cornea used in a transplant is removed from the healthy eye of a person who has died and donated their cornea.

Corneas are rigorously checked for disease and infection before being transplanted.

Post Procedure

Most people have to stay in hospital for a night after a full-thickness cornea transplant (penetrating keratoplasty). 

You may be able to go home the same day if you have a partial-thickness transplant. 

Your eye may be covered with an eye pad or plastic shield, which is removed the day after the procedure.

When it’s taken away, you may find that your sight is blurred. This is normal.

There should not be serious pain after the operation, but there might be some swelling and discomfort.

If you have had an endothelial keratoplasty – a type of partial-thickness transplant that uses an air bubble to hold the donated cornea in place – you may be asked to lie on your back as much as possible in the first few days after surgery.

This can help hold the transplant in the correct place. The air bubble will be absorbed after a few days.

Looking after your eye

Once you return home after the procedure, you’ll need to take good care of your eye.

Some important points to remember include:

  • do not rub your eyes
  • during the first weeks after surgery, avoid strenuous exercise and heavy lifting
  • if you have a job that does not involve physical strain, you can return to work 2 to 3 weeks after surgery
  • if your job involves manual labour, you should wait for 3 to 4 months
  • avoid smoky or dusty places as this could irritate your eyes
  • if your eye is sensitive to light, wearing sunglasses can help
  • avoid contact sports and swimming until you’re given clear advice that it’s safe, and wear protective goggles when resuming contact sports
  • bath and shower as normal, but be careful not to get water in your eye for at least a month
  • do not drive until your specialist tells you it’s possible

You’ll usually be given a patch to wear at night for the first few weeks after surgery to help protect your eye.

For all types of cornea transplant, you have to use steroid or antibiotic eyedrops daily.

These are normally required for several months, although some people may need to use them for more than a year.

The drops reduce swelling and inflammation, and help prevent infection and rejection.

Follow-up

At first you’ll need to attend regular follow-up appointments. These should gradually become less frequent over time.

If stitches were used to hold the transplant in place, these are initially left in place to allow the cornea to heal. They’re usually removed after about a year.

Your vision

The time it takes for your vision to return after a cornea transplant can range from as little as a few weeks up to a year or more.

This largely depends on the specific procedure used. In some cases, your vision may fluctuate between being better or worse before it settles down.

It’s likely you’ll need corrective lenses (either glasses or contact lenses), even after your vision returns.

In some cases, a small operation called arcuate keratotomy (AK) or laser treatment is used to correct vision problems after your eyes have healed.