Types Of Cornea Transplant, Procedure, and Recovery

Overview

A cornea transplant, also called keratoplasty or corneal graft, is a surgical procedure to replace all or a part of your damaged cornea with healthy corneal tissue from a donor.

A cornea transplant is designed to restore vision to a person with a damaged cornea, reduce pain, and improve the appearance of a damaged or diseased cornea.

What Is The Cornea?

The cornea is the transparent front layer of the eye that covers the iris (the colored part) and the pupil(the black dot in the center of the iris).

The cornea’s function is to help focus light beams on to the retina (the light-sensitive film at the back of the eye) and then transmit that message to the brain.

If the cornea becomes damaged, the light reaching the retina will be blocked and as a result, the image transmitted to the brain can be unclear and distorted. The cornea also protects the eyes against microbes and dirt, and damaging UV lights. 

When damaged, the cornea will become less clear or its shape will alter.

The cornea is made up of three main layers of tissue, with two thinner layers of the membrane between them.

Why Is Cornea Transplant Done?

A cornea transplant is most often performed to restore vision to a person who’s cornea is not functioning as it should.

Conditions that damage your corneas and restrict your ability to see clearly include:

  • Keratoconus: Where the cornea bulges outward and is cone-shaped instead of being dome-shaped
  • Fuchs’ dystrophy: A condition in which the inner layer (endothelial) cells of the cornea die, and the cornea becomes thick and swollen. This condition makes the vision blurred
  • Thinning of the cornea
  • Cornea scarring: Caused by infection or injury
  • Clouding of the cornea
  • Swelling of the cornea
  • Corneal ulcers: Including those caused by infection
  • Complications due to previous eye surgery
  • Bullous keratopathy: The swelling of the cornea shaped like a blister that causes pain and discomfort in the eye and results in a blurred vision
  • Keratitis: The inflammation of the cornea either caused by viruses, bacteria, fungi, or parasites
  • Corneal perforation: where the cornea becomes damaged and a small hole develops in it

What Are The Symptoms Of A Damaged Cornea?

If you have a damaged cornea, you may experience symptoms including:

  • Pain and discomfort in the eye
  • Blurred vision
  • Cloudy vision

Your ophthalmologist will determine the cause and other possible treatments that may treat and resolve these symptoms. If your cornea cannot be repaired using other procedures, your surgeon may recommend a cornea transplant.

How To Prepare

Before your cornea transplant surgery, your doctor will:

  • Do a thorough eye exam. Your surgeon will look for any possible conditions that may later cause any post-operative issues.
  • Take measurements of your eye. They will evaluate and determine the size of the donor cornea you need.
  • Take your medical history and go over any medications and supplements you are taking. Your physician may suggest that you avoid taking specific medications or supplements before or after your transplant surgery.
  • Treatment for other eye complications. If you have other eye problems such as infection or inflammation, your surgeon will address them first, making sure that these conditions don’t reduce the chances of a successful transplant.

During your initial doctor’s appointment, your eye surgeon will explain how the surgery works, what the risks and side effects are, and the results you can expect after your transplant.

 

Finding A Donor Cornea

Typically the corneas that are used as donors in transplant surgeries, are corneas donated from diseased patients. Many otherwise healthy people decide to have their corneas available as donors for transplants after they are no longer alive, and so there are more corneas available for transplantation.

For other organ transplantations such as livers and kidneys, patients may need to wait in long waiting lists to be able to receive the organ they need, but with corneal transplants, people generally don’t have to wait that long for donor organs.

Corneas may not be used from donors who died from unknown causes and had other conditions such as: 

  • Certain central nervous system conditions
  • Infections
  • Previous eye surgery or eye conditions

Types Of Cornea Transplants

The type of cornea transplant that your doctor recommends will depend on the parts of the cornea that are damaged and need to be replaced.

Usually, surgeons transplant the entire thickness of the cornea (full-thickness), however,  with new methods and technical advancements, it is possible in some cases to only have a part of the cornea transplanted (partial-thickness).

These are the main types of cornea transplants:

  1. Full-Thickness Transplant or Penetrating Keratoplasty (PK)
  2. Partial-Thickness Transplant, which in itself can be divided into:
  3. Transplanting the front portion of the cornea
  4. Transplanting the back portion of the cornea

During The Procedure

Before your surgery, your surgical team will sedate you to help you feel relaxed and comfortable, and also give you local numbing anesthetics. This means that you will be awake for the surgery but won’t feel any kind of pain for the process of the surgery. 

Other times your surgeon may decide to perform the procedure under general anesthesia.

Full-Thickness Transplant/ Penetrating Keratoplasty (PK)

Full-thickness transplant (penetrating keratoplasty), is considered to be the most common type of cornea transplant.

The operation may be performed with local or general anesthesia, and will usually take around 45 minutes to complete. 

During surgery,  your doctor will cut through the entire thickness of the diseased or abnormal cornea to remove a small button-sized disk of corneal tissue. This is done with an instrument called a trephine that acts like a cookie cutter and makes the precise circular cut.

The donor cornea, which has been shaped and cut specifically to fit the recipient’s eye measurements, will be placed at the opening of the eye.

  Your surgeon will then stitch the new cornea into its place. The stitches will be removed at a follow-up appointment after your surgery when you see your eye doctor.

In some cases, artificial corneas (keratoprosthesis) are used as the new replacement cornea, where patients aren’t qualified to receive donor corneas.

If your surgery is done with a local anesthetic, you will not see through that eye during the transplantation process, due to the anesthetic temporarily disabling the eye.

After a full-thickness transplant, you will be required to stay in the hospital for 1 night.

Partial-Thickness Transplant

Some cornea conditions don’t require a full-thickness cornea transplant and other kinds of surgeries are offered instead that remove only specific layers of cornea tissue.

Depending on the exact layer of diseased tissue that needs to be replaced, your surgeon may use various techniques to perform the surgery.

Partial-thickness transplants usually involve either the replacement of either the front portion of the cornea or the back portion.

Transplanting The Front Portion Of The Cornea

There are 2 main methods for transplanting the front parts of the cornea, these include:

  1. Anterior Lamellar Keratoplasty (ALK) – only involving the removal and replacement of the outer (front) layers of the cornea 
  2. Deep Anterior Lamellar Keratoplasty (DALK) – only involving the removal and replacement of the outer and middle layers of the cornea. This technique keeps the inner (back) layers intact

Just like full-thickness transplantation, during both of these procedures, your surgeon will use stitches to place the donor cornea in its place.

Transplanting The Back Portion Of The Cornea/Endothelial keratoplasty (EK)

The main techniques for Endothelial keratoplasty (EK) include:

  1. Descemet’s stripping endothelial keratoplasty (DSEK) – involving the removal and replacement of the inner lining of the cornea together with about 20% of the corneal supporting tissue (corneal stroma)
  2. Descemet’s membrane endothelial keratoplasty (DMEK) – involving the removal and replacement of the inner layer of cells of the cornea

Both of these techniques have lower risks of complications and result in faster visual recovery.

Unlike full-thickness and front portion cornea transplant, your doctor will not use stitches to place the cornea in place. Instead, the cornea tissue will be kept in place by a temporary air bubble.

After the surgery, your team may ask you to lie on your back as much as possible in the first few days after surgery for recovery.

After The Procedure

Usually, after a full-thickness cornea transplant (penetrating keratoplasty), you will be asked to spend a night in the hospital. 

However, after a partial-thickness cornea transplant, your doctor may allow you to return home the same day after the surgery.

Some common side effects of cornea transplant surgery include swelling and discomfort, but you should not experience severe pain.

After your cornea transplant is performed, you may:

  • Be asked to take several medications. Your doctor may prescribe steroid or antibiotic eye drops, and other oral medications to help reduce any postoperative swelling, pain, or infection.
  • Wear an eye patch. For the first few weeks after surgery, you will have to wear an eyepatch to help protect your eye.
  • Make additional follow-up appointments. During these exams, your doctor will evaluate the overall results and check for any complication after the first year of surgery.
  • Be asked to protect your eye from injury. Your transplant team will give you instructions as to how to look after your eye for recovery. Keep in mind to not overwork your eye, and ask your doctor when it’s safe to resume your normal daily activities.
  • Just like any other transplant surgery, you will have to take extra precautions to avoid harming your eye.

Recovery And After-Care At Home

Taking proper and good care of your eye can be vital in keeping your cornea transplant successful, lowering your post-operative complications, and reducing the risks of rejection. 

Some important points to remember:

  • 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 labor, you should wait for 3 to 4 months
  • Avoid smoky or dusty places as this could irritate your eyes
  • Do not rub your eyes
  • If your eye is sensitive to light, wearing sunglasses can help
  • Avoid contact sports and swimming until you’re cleared by your doctor to do so and are ensured 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 clears you

 

Risks

A cornea transplant is a relatively safe procedure, however, like other medical procedures, it carries a slim chance of post-operative complications, such as:

  • Eye infection
  • Increased risk of clouding of the eye’s lens (cataract)
  • Pressure increase within the eyeball (glaucoma)
  • Problems with the stitches used to secure the donor cornea
  • Swelling of the cornea
  • Rejection of the donor cornea

Signs And Symptoms Of Cornea Rejection

Rejection happens when in some cases, your body’s immune system mistakenly attacks the donor cornea. About 10% of cornea recipients experience rejection after surgery. In these cases, there may be a need for additional cornea transplant surgery and medical treatment.

Signs and symptoms of rejection include:

  • Foggy Or Clouded Vision
  • Eye Pain
  • Redness
  • Sensitivity To Light (Photophobia)

If you start to develop any of these symptoms, be sure to make an appointment with your eye doctor.

Vision Problems

Your visual recovery after surgery heavily depends on the specific procedure your surgeon used and can take as little as a few weeks to up to maybe a year or more, to regain desired visual capabilities.

For some patients, the vision may go from better to worse or vice versa before it becomes settled.

You’ll likely need either glasses or contact lenses, to help with your vision, even after it returns.

In some cases, doctors recommend a minor procedure called arcuate keratotomy (AK) or laser treatment to correct vision problems after your eyes have healed.

Success Rates Of Cornea Transplants

Because the rates vary so greatly, you should ask your doctor about the rate of success in your specific situation and condition. Note that in most cases vision is usually blurred after surgery but will be improved as time passes.

The rates of long-term outcomes depend on many factors. These include:

  • The initial cause of the cornea damage
  • Your doctor’s technique during surgery
  • The expertise of the surgeon
  • Your immune system acceptance for any donor organs

Bottom Line

If you have a damaged cornea, you and your ophthalmologist will discuss your options for improving your vision. For people with a deeply scarred or swollen cornea, transplant surgery can restore clear vision. Discuss with your doctor what form of treatment is best for you.

Be sure to take advantage of our free medical consultation services. Our experts are ready to happily address any questions or uncertainties regarding your conditions or treatments.

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