Corneal Transplant

Introduction

The cornea is the clear, dome-shaped window at the front of your eye. It focuses light onto the back of the eye so you can see. When the cornea becomes scarred, swollen, thinned, or cloudy, vision can drop sharply — sometimes to the point where glasses and contact lenses no longer help.

A corneal transplant is surgery to replace damaged corneal tissue with healthy tissue from a human donor. The medical name for the operation is keratoplasty. Modern techniques allow surgeons to replace either the full cornea or only the specific layer that has failed, which has changed how quickly people recover and how well their vision returns.

If your ophthalmologist has discussed a corneal transplant with you, this guide explains what the surgery involves, the main techniques used today, how it is performed, what recovery looks like, and how to protect the new tissue for the long term. It is written for patients and families who are planning the next step in care, not for someone trying to work out a diagnosis.

What Is a Corneal Transplant?

A corneal transplant is the surgical replacement of part or all of the cornea with healthy donor tissue. The donor tissue comes from someone who has chosen to donate their eyes after death. It is recovered, tested, and prepared by an eye bank under strict medical standards before being released to the surgeon.

1. Epithelium — the thin outer protective layer
2. Bowman’s layer — a tough supporting layer beneath the epithelium
3. Stroma — the thick middle layer that gives the cornea most of its strength and shape
4. Descemet’s membrane — a thin elastic layer
5. Endothelium — the innermost single layer of cells that pumps fluid out of the cornea to keep it clear

Different diseases damage different layers. A scar from an old infection may affect the stroma. Fuchs’ dystrophy and bullous keratopathy damage the endothelium. Keratoconus thins and reshapes the stroma. Because each layer can fail on its own, surgeons can often replace only the layer that has failed rather than the whole cornea. This is the principle behind the modern partial-layer transplants described later in this article.

Why Is a Corneal Transplant Performed?

A corneal transplant is considered when the cornea has become so damaged that vision cannot be restored by glasses, contact lenses, medication, or less invasive surgery. The most common reasons include:

• Keratoconus — a condition where the cornea thins and bulges outward into a cone shape, distorting vision
• Fuchs’ endothelial dystrophy — a genetic loss of the inner pump cells of the cornea, causing swelling and cloudiness
• Bullous keratopathy — corneal swelling that can occur after cataract surgery or other intraocular procedures
• Corneal scarring from past infections, including bacterial, viral (such as herpes simplex), fungal, or parasitic keratitis
• Corneal injury from trauma, chemical burns, or foreign bodies
• Failed previous corneal transplant requiring a repeat graft
• Congenital corneal opacities in children, where the cornea is cloudy from birth
• Severe corneal ulcers that have not responded to medical treatment and threaten the structure of the eye

The decision to operate depends on how much vision has been lost, whether other treatments have already been tried, the health of the rest of the eye (including the retina, lens, and optic nerve), and the underlying cause of the corneal damage.

Who Is a Candidate?

A person is generally considered for a corneal transplant when:

• Vision in the affected eye is reduced enough to affect daily life
• The cause of vision loss is clearly the cornea, not another part of the eye
• Glasses, specialty contact lenses, and medications have not provided adequate vision
• The rest of the eye is healthy enough to benefit from a clear cornea — meaning the retina and optic nerve can still carry visual signals to the brain
• The patient is well enough for surgery and can follow the long aftercare routine

A corneal transplant is not always the right choice. If the retina or optic nerve is severely damaged from another condition, clearing the cornea may not improve vision meaningfully. If there is active, uncontrolled infection or severe ocular surface disease, surgery is usually delayed until the eye is calmer. Patients with severe dry eye, poorly controlled glaucoma, or limbal stem cell failure may need other treatments before a transplant is considered, because these conditions raise the risk of graft failure.

Suitability is decided after a detailed eye examination that typically includes visual acuity testing, slit-lamp examination, corneal topography (a map of the cornea’s shape), pachymetry (corneal thickness measurement), specular microscopy (a count of the endothelial cells), and optical coherence tomography (OCT) imaging. A retinal evaluation is usually done to confirm the back of the eye is healthy.

Alternatives to Corneal Transplant

Not every corneal problem needs a transplant, and not every transplant decision is urgent. Depending on the diagnosis, your ophthalmologist may discuss one or more of the following alternatives or interim steps:

Specialty Contact Lenses

For keratoconus and irregular corneas, rigid gas-permeable lenses, hybrid lenses, or scleral lenses can often restore good vision without surgery. Many people with keratoconus do well with scleral lenses for years and never need a transplant.

Corneal Cross-Linking (CXL)

Corneal cross-linking is a procedure that uses riboflavin (vitamin B2) drops and ultraviolet light to strengthen the cornea. It is used to slow or stop the progression of keratoconus and similar thinning disorders. It does not reverse damage already done, but it can prevent the disease from worsening enough to need a transplant.

Phototherapeutic Keratectomy (PTK)

PTK uses an excimer laser to remove a thin layer of damaged or scarred tissue from the surface of the cornea. It can be useful for superficial scars, recurrent erosions, and certain corneal dystrophies, and may delay or avoid the need for a transplant.

Medical Treatment

For corneal swelling (edema), hypertonic saline drops or ointments can pull fluid out of the cornea and improve clarity, at least temporarily. Antiviral medications can suppress recurrent herpes simplex keratitis. Treating the underlying infection or inflammation may stabilise the cornea enough to avoid surgery.

Intracorneal Ring Segments

For keratoconus, small plastic ring segments can be inserted into the cornea to flatten its shape and improve vision. This can sometimes delay or replace the need for a transplant in earlier-stage disease.

When these options have been tried without success, or when the cornea has reached a stage where they cannot help, a transplant becomes the next step.

Surgical Approaches to Corneal Transplant

Penetrating Keratoplasty (PK)

Penetrating keratoplasty is a full-thickness transplant. A circular section of the entire damaged cornea is removed and replaced with a matching circular section of donor cornea, held in place with very fine sutures. The sutures stay in for many months and are removed gradually.

PK has been the traditional corneal transplant for decades and is still used when all layers of the cornea are damaged — for example, in deep scars, full-thickness infections, advanced keratoconus with stromal scarring, or failed previous grafts. Vision recovery after PK is slow because the cornea has to heal completely and the sutures cause some astigmatism (uneven curvature) until they are removed. Final vision may take 12 months or longer to stabilise.

Deep Anterior Lamellar Keratoplasty (DALK)

DALK is a partial-thickness transplant in which the front layers of the cornea (the epithelium, Bowman’s layer, and most of the stroma) are replaced, but the patient’s own healthy endothelium and Descemet’s membrane are preserved. It is mainly used for keratoconus and stromal scars where the inner layer is still working.

Because the patient’s own endothelium is kept, the risk of endothelial rejection is much lower than with PK. The eye is also structurally stronger because it has not been opened all the way through. DALK is technically demanding and recovery still takes several months, but it is often preferred when the disease is limited to the front of the cornea.

Descemet Membrane Endothelial Keratoplasty (DMEK)

DMEK is a partial-thickness transplant that replaces only the innermost layer — Descemet’s membrane and the endothelium. It is used for diseases of the endothelium such as Fuchs’ dystrophy and bullous keratopathy.

The damaged layer is stripped away through a small incision, and an ultra-thin sheet of donor tissue is inserted and positioned with an air or gas bubble that holds it in place while it attaches. There are usually no sutures. DMEK offers the fastest visual recovery of all corneal transplant techniques, often within weeks, and the lowest rejection rate. The trade-off is that it is technically demanding and requires the patient to lie face-up for periods after surgery to keep the bubble in position.

Descemet Stripping Automated Endothelial Keratoplasty (DSAEK)

DSAEK is another partial-thickness technique for endothelial disease. Like DMEK, it replaces the inner layer of the cornea, but the donor tissue used is slightly thicker because it includes a thin layer of stroma. DSAEK is often chosen when DMEK is not technically suitable — for example, in eyes with unusual anatomy, previous glaucoma surgery, or where the surgeon expects difficulty positioning the thinner DMEK tissue. Visual recovery is faster than PK but generally a little slower than DMEK.

Keratoprosthesis

For a small number of patients in whom standard donor transplants have repeatedly failed, or whose ocular surface is so damaged that a biological graft cannot survive, an artificial cornea (keratoprosthesis) may be considered. This is a specialised option reserved for difficult cases at experienced centres.

The choice between PK, DALK, DMEK, and DSAEK is made by the cornea surgeon based on which layer is diseased, the overall condition of the eye, and the surgeon’s experience with each technique.

Preparing for a Corneal Transplant

Preparation for a corneal transplant generally takes place over a few weeks. Donor tissue is sourced through a registered eye bank, which screens donors for infections and checks the quality of the tissue. The waiting time depends on tissue availability, but in most centres it is relatively short for routine cases.

Before surgery, you will have:

• A detailed eye examination, including slit-lamp evaluation and imaging of both the cornea and the back of the eye
• Measurements that help the surgeon plan the size and technique of the graft
• A general health check, blood tests, and sometimes an ECG, especially if general anaesthesia is planned
• A discussion of your current medications — blood thinners, for example, may need to be adjusted
• A review of eye drops you may need to start before surgery

You will usually be asked not to eat or drink for several hours before the operation. Most corneal transplants are done as day-care or short-stay procedures, but you will need someone to take you home and stay with you for the first day.

What Happens During the Surgery

Corneal transplants are usually done under local anaesthesia with sedation, meaning the eye is numbed with injections or drops and you are relaxed but awake. General anaesthesia is used for children and for some adults, depending on the case.

1. Anaesthesia and positioning. The eye is numbed and an instrument gently holds the eyelids open. You will not see the surgery happening.
2. Removing the damaged tissue. The surgeon removes the diseased part of your cornea. For PK, a circular full-thickness disc is cut out. For DALK, the front layers are dissected away while the inner layer is left. For DMEK and DSAEK, the inner layer alone is stripped through a small side incision.
3. Placing the donor tissue. The prepared donor tissue is positioned in the eye. In PK and DALK it is stitched in place with very fine nylon sutures. In DMEK and DSAEK, an air or gas bubble is injected to push the thin donor layer against the back of the cornea so it can attach.
4. Closing up. The eye is checked, antibiotic and anti-inflammatory drops are given, and a protective shield is placed over the eye.

The operation typically takes between 45 minutes and 2 hours, depending on the technique and complexity. You should not feel pain during the procedure. After surgery, your eye will be covered, and you will rest in the recovery area before going home.

Recovery and Healing

Recovery from a corneal transplant is gradual, and the timeline depends heavily on which technique was used. The cornea heals slowly because it does not have its own blood supply.

The First Few Days

In the first day or two, you can expect:

• Mild to moderate discomfort or a gritty feeling in the eye, usually controlled with simple painkillers
• Blurred vision — this is normal and does not mean the surgery has failed
• Watering, sensitivity to light, and some redness
• For DMEK and DSAEK patients: a need to lie flat on your back for several hours a day to keep the air or gas bubble in position

You will use multiple eye drops — typically a steroid drop to prevent rejection and an antibiotic drop to prevent infection. The drop schedule is intensive at first and tapers down over weeks to months.

The First Few Weeks

You will be seen by your surgeon frequently in the early weeks. The eye is checked for healing, graft attachment, intraocular pressure, and any early signs of rejection. Activities like reading and screen use are usually allowed in moderation. Heavy lifting, swimming, contact sports, eye rubbing, and dusty environments are avoided.

Months to a Year

• DMEK — vision often improves substantially within 4 to 8 weeks, with further refinement over a few months
• DSAEK — vision typically improves over 2 to 6 months
• DALK — vision usually stabilises by 6 to 12 months as sutures are gradually adjusted or removed
• PK — full visual stabilisation can take 12 to 18 months, sometimes longer, because all sutures need to come out and the cornea continues to remodel

Steroid drops are usually continued for many months, often at a low dose for a year or longer. Glasses or contact lenses are frequently prescribed once the cornea has settled to fine-tune the final vision.

Aftercare Instructions Generally Given

• Use all prescribed eye drops exactly as instructed
• Do not rub or press on the operated eye
• Wear the protective shield at night for the first few weeks
• Use protective eyewear during the day, especially in dusty or windy conditions
• Avoid swimming pools and hot tubs until cleared
• Avoid heavy lifting and strenuous exercise for the period your surgeon advises
• Attend every scheduled follow-up appointment, even if the eye feels fine

Risks and Complications

Corneal transplants are generally safe, and the techniques in use today have improved outcomes considerably. However, like any surgery, there are risks. Knowing them helps you watch for problems early, which is when they are most treatable.

Graft Rejection

Graft rejection is the immune system recognising the donor tissue as foreign and attacking it. It is one of the most important complications to be aware of because it can often be reversed if treated early. Rejection is more common with PK than with DALK, DMEK, or DSAEK, but it can happen with any technique.

• Redness
• Sensitivity to light
• Vision changes (blurring or drop in vision)
• Pain

If any of these appear, contact your eye surgeon urgently. Prompt treatment with intensive steroid drops can often reverse the rejection and save the graft.

Graft Failure

Graft failure means the donor tissue has lost its clarity and is no longer functioning. It may follow rejection that could not be reversed, or it may happen gradually over years as the donor endothelial cells naturally decline. A failed graft can sometimes be replaced with a repeat transplant.

Other Possible Complications

• Infection — either at the wound or inside the eye (endophthalmitis), which is rare but serious
• Raised eye pressure (glaucoma) — either from the surgery itself or from long-term steroid drops
• Cataract — clouding of the lens, which may develop or worsen after surgery
• Astigmatism — uneven curvature of the cornea, particularly after PK; usually managed with glasses, contact lenses, or sometimes a small adjustment procedure
• Wound leak or suture problems — loose or broken sutures can cause discomfort and may need to be removed
• Bubble dislocation in DMEK or DSAEK — if the donor tissue does not attach properly, a repeat air injection (“rebubbling”) may be needed
• Recurrence of the original disease — for example, herpes simplex infection can return in the new graft

Most complications are manageable when caught early, which is why regular follow-up matters even when the eye feels well.

Life After a Corneal Transplant

For most people, life after a corneal transplant slowly returns to normal as vision improves and the eye settles. There are, however, some long-term changes to be aware of.

Vision

Vision after a transplant is usually much clearer than before, but it is rarely as sharp as a normal healthy eye without correction. Many people need glasses or contact lenses for fine vision after the cornea has healed. After PK, astigmatism is common and may require rigid contact lenses for best vision. After DMEK and DSAEK, vision is often closer to natural.

Daily Activities

Long-Term Eye Drops and Follow-up

Steroid eye drops are typically used at a low dose for a year or more, sometimes indefinitely at a minimal dose, to lower the chance of rejection. Eye pressure must be monitored because long-term steroid use can raise it. Follow-up visits continue for life, even if they become less frequent over time.

Donor Tissue and Long-Term Outlook

Donor corneas can last many years, often decades. The endothelial cells gradually decline over time after any transplant, but most patients enjoy good vision for a long period. If a graft eventually fails, a repeat transplant is usually possible.

Corneal Transplant in Children

Corneal transplants in children are less common than in adults and require a different approach. Children may need a transplant for congenital corneal opacities such as Peters anomaly or sclerocornea, for severe corneal scarring after trauma or infection, or for inherited corneal dystrophies.

Surgery in children is technically more challenging because the eye is smaller and softer, the immune response is more vigorous, and the risk of rejection is higher than in adults. General anaesthesia is required, and post-operative care — drops, examinations, and protection from eye rubbing — depends heavily on the parents.

Children also have a higher risk of amblyopia (“lazy eye”), where the brain does not develop normal vision in the operated eye even after the cornea is clear, particularly if the cornea was cloudy from a very young age. Patching the other eye, glasses or contact lenses, and visual rehabilitation are often part of long-term care.

Decisions about corneal transplants in children are made by paediatric ophthalmologists and cornea specialists together, weighing the chance of useful vision against the risks of surgery and the demands of long-term follow-up.

Frequently Asked Questions

Will I be awake during the surgery?

Most adults have a corneal transplant under local anaesthesia with sedation. The eye is numbed and you are relaxed but awake. You will not see the surgery and should not feel pain. General anaesthesia is used for children and in some adult cases.

How long until I can see clearly?

This depends on the technique. With DMEK, vision often improves within a few weeks. With DSAEK, it takes a few months. With DALK and PK, full visual stabilisation can take 6 to 12 months or longer, especially after sutures are removed. Patience is part of recovery.

Will I still need glasses or contact lenses after surgery?

Many people do, particularly after PK, where the cornea often develops some astigmatism. Glasses, soft lenses, or rigid contact lenses can fine-tune the final vision once the cornea has stabilised.

How do I know if my body is rejecting the graft?

Watch for the RSVP signs: Redness, Sensitivity to light, Vision changes, and Pain. Any of these should prompt an urgent call to your eye surgeon. Early treatment can often reverse rejection.

How long does a corneal transplant last?

Many grafts remain clear for a decade or longer, and some last for the rest of the patient’s life. The endothelial cells decline gradually with time, so a graft may eventually need replacement. A repeat transplant is usually possible.

Can both eyes be operated on at the same time?

Generally, surgeons treat one eye at a time and wait for it to stabilise before operating on the other. This protects against complications affecting both eyes at once.

Is there any risk of catching a disease from the donor tissue?

Donor tissue is screened thoroughly by eye banks for infections including HIV, hepatitis, and other transmissible diseases before it is released for surgery. The risk of disease transmission is very low.

Can corneal disease come back after a transplant?

Some conditions can recur. For example, herpes simplex keratitis can come back in the new cornea, and certain corneal dystrophies can slowly redevelop. Long-term follow-up helps catch recurrence early.

How soon can I travel after surgery?

Air travel itself does not damage the eye, but the early weeks include frequent follow-up visits and intensive drops, and any urgent problem (such as a suspected rejection) needs prompt access to your surgeon. Most surgeons advise staying close to the operating centre for the first few weeks. Discuss your specific timeline with your eye care team.

Can I rub my eye after it has healed?

Even after healing, eye rubbing should be avoided. The cornea is never quite as strong as it was before surgery, especially after PK, and forceful rubbing or trauma can damage the graft.

Conclusion

A corneal transplant is one of the oldest and most successful tissue transplants in medicine, and modern techniques have made it more precise, safer, and faster-healing than ever. By replacing only the layer that has failed — whether through PK, DALK, DMEK, or DSAEK — surgeons can match the operation closely to the disease.

Recovery takes patience. Vision returns gradually, drops continue for many months, and the eye needs protection and regular checks for life. The reward, for most people, is restored sight in an eye that had lost it — the ability to read, work, recognise faces, and move through the world with confidence again.

The decisions about whether to have a transplant, which technique to use, and how to manage long-term care are made together with your cornea specialist, based on the specific cause of your corneal disease and the overall health of your eye. Understanding the procedure and what to expect afterwards is an important part of that conversation.