Corneal transplant

The cornea is the transparent dome at the front of the eye. It does two jobs: it lets light in, and it does about two-thirds of the eye's focusing. When it loses clarity or regular shape, vision degrades no matter how healthy the retina behind it is. A corneal transplant, or keratoplasty, replaces the diseased tissue with clear donor tissue so light can pass and focus properly again.

The cornea has a property that makes transplantation unusually successful: it has no blood vessels of its own. Blood vessels are how the immune system finds foreign tissue, so an avascular cornea is partly hidden from it — a phenomenon called immune privilege. This is why corneal grafts succeed at rates organ transplants cannot match, and why most recipients need only eye drops rather than the systemic immunosuppression a kidney or heart requires.

The last two decades have changed this operation more than any other in ophthalmology. Where surgeons once replaced the entire thickness of the cornea for almost every problem, they now identify which layer has failed and replace only that. Somebody with an unhealthy inner cell layer receives a graft a few tens of microns thick; somebody with front-surface scarring keeps their own healthy inner layer. The result is faster visual recovery, stronger eyes and less rejection.

What a graft cannot do is fix anything behind it. If the retina or optic nerve is damaged, clearing the window will not restore the sight those structures were responsible for. A careful assessment before surgery exists precisely to establish how much vision is recoverable, and a surgeon who cannot give you a realistic expectation has not finished assessing you.

Penetrating keratoplasty replaces the full thickness of the central cornea with a matching disc of donor tissue, held by very fine sutures. It remains necessary where the whole thickness is scarred or thinned, and where an eye is too damaged for a layered approach. Its drawbacks are the reason surgeons avoid it when they can: sutures stay for a year or longer, astigmatism is often substantial, visual recovery takes many months, and the eye remains structurally weaker than a natural one indefinitely.

Deep anterior lamellar keratoplasty replaces the front layers while keeping the patient's own innermost cell layer. Because that layer is what the immune system attacks hardest, keeping it removes the risk of the most dangerous form of rejection almost entirely. It suits keratoconus and front-surface scarring where the inner layer is still healthy, and it is technically demanding.

Endothelial keratoplasty replaces only the inner cell layer, which is the layer that fails in Fuchs dystrophy and in corneal swelling after cataract surgery. In DSAEK a thin disc of tissue with a supporting layer is inserted; in DMEK only the membrane and its cells, a graft so thin it is handled as a scroll. DMEK gives the best and quickest visual recovery and the lowest rejection rate; DSAEK is easier to handle and often preferred in complicated eyes.

Both are performed through a small incision, with the graft positioned by an air or gas bubble that presses it against the inside of the cornea while it adheres. That is why patients are asked to lie flat and face upwards for a period afterwards, and it is a genuine commitment rather than a suggestion.

A keratoprosthesis is an artificial cornea, used where donor tissue has failed repeatedly or where the eye's surface is too hostile for a graft to survive. It can restore sight in eyes that have run out of other options, but it requires lifelong monitoring for serious complications.

The commonest reason worldwide is failure of the inner cell layer. Those cells pump fluid out of the cornea to keep it clear, they do not regenerate, and when their number falls too far the cornea swells and clouds. This happens in Fuchs endothelial dystrophy, an inherited condition that usually declares itself in middle age, and after cataract or other intraocular surgery when the cells have been depleted. These eyes are treated by endothelial keratoplasty.

Keratoconus is the second large group. The cornea thins and bulges into a cone, distorting vision in a way glasses cannot correct. Most people with keratoconus never need a transplant: rigid or scleral contact lenses manage many, and cross-linking halts progression when it is caught early. Surgery is considered when lenses can no longer be tolerated or the cornea has scarred, and DALK is usually preferred.

Scarring is the third: after infection — bacterial, herpetic, fungal or parasitic — after injury, or after chemical burns. Here the choice of operation depends on how deep the scar goes and whether the eye surface is healthy enough to support a graft.

Other indications include inherited corneal dystrophies, corneal thinning or perforation needing urgent tectonic grafting to preserve the eye, and regrafting after a previous transplant has failed.

Assessment establishes what is realistic. It maps the corneal shape and thickness, counts the inner cells, and examines the retina and optic nerve — often with scanning that sees past a cloudy cornea. If sight is limited by disease behind the cornea, that must be known before surgery rather than discovered afterwards. Dry eye, lid disease and glaucoma are identified and treated first, because each affects whether a graft survives.

Corneal tissue is assessed on the health of the tissue itself rather than on any relationship to the recipient. There is no matching to a family member, no blood group requirement in routine practice, and no tissue typing for most grafts.

Eye banks screen every donor for transmissible infection using blood testing and a review of medical and social history, and they exclude donors with conditions that could be transmitted or that damage the tissue — certain infections, some neurological diseases, and cancers affecting the eye. Tissue is then examined by microscope, and for endothelial grafts the inner cells are counted, since that count predicts how long the graft will last.

Donor age matters less than people expect, and eyesight during life does not matter at all: someone who wore strong glasses can be an excellent donor, because spectacles correct the shape of the eye rather than the health of the cornea. What matters is cell count, clarity, and the time between death and preservation.

Storage is what makes scheduling possible. Depending on the preservation method, tissue remains usable for roughly one to two weeks in cold storage, and longer in organ culture systems used widely in Europe. Many banks now supply endothelial grafts pre-cut or pre-loaded, prepared by the bank rather than the surgeon, which reduces the risk of damaging a delicate graft in theatre.

What this means practically is that supply, not compatibility, determines waiting. In a country whose donation programme functions well, surgery can often be scheduled within weeks. Where supply is short, waiting lists run into many months, and that gap is the honest reason many people look abroad.

Corneal transplantation is safer than organ transplantation, and it is not without risk. The eye is small, and complications that would be minor elsewhere matter here.

Rejection is the risk everyone asks about. The immune system recognises the donor tissue and attacks it, most often in the first year but possibly at any time afterwards — including many years later. Its warning signs are specific and worth memorising: redness, sensitivity to light, falling vision and discomfort. Caught early, most episodes are reversed with intensive steroid drops. Ignored for days, a rejection episode can destroy the graft permanently. Risk is highest after full-thickness grafts and lowest after DMEK.

Graft failure can happen without rejection, when the inner cells simply decline below the number needed to keep the cornea clear. This is the commonest reason a graft eventually stops working after many years, and it can be treated by regrafting.

Endothelial grafts can detach before they adhere, which is why posturing matters; a detached graft is usually managed by injecting another bubble to reposition it. In full-thickness surgery, sutures may loosen, break or cause irritation and infection, and each loose suture needs removing promptly.

Infection inside the eye is uncommon but serious, and any sudden increase in pain, redness or discharge should be treated as an emergency rather than watched. Raised eye pressure is frequent, partly from the steroid drops themselves, and needs monitoring because glaucoma damage is silent and permanent.

Underlying disease can also return in the new tissue. Herpes simplex keratitis in particular can recur in a graft, which is why recipients with a history of it stay on long-term antiviral treatment.

Assessment for corneal surgery is an eye examination rather than a whole-body work-up, and it is usually completed in one or two visits.

The examination establishes what is wrong and how deep it goes: slit-lamp examination, corneal topography and tomography to map shape and thickness, and specular microscopy to count the inner cells. Imaging of the layers guides the choice between a full-thickness and a layered operation.

The eye behind the cornea is assessed too, because it determines what vision is achievable. Where the cornea is too cloudy to see through, ultrasound and other scanning are used to check the retina and optic nerve. This is the step that produces a realistic expectation, and it is the step to insist on if it has not been done.

Surface problems are treated before surgery rather than after. Dry eye, blepharitis, lid position abnormalities and any active infection are addressed first, because a graft placed on an unhealthy surface is a graft that fails early. Glaucoma is identified and controlled.

Practical preparation is straightforward but specific. Arrange somebody to take you home, since you cannot drive afterwards. Understand the drop regimen before the day, because it starts immediately and is frequent. If you are having an endothelial graft, know how long you will need to lie flat and arrange your household around it. And if you are travelling for surgery, establish who will see you at one week, one month, three months and beyond — and get that in writing before you fly.

Cornea transplant surgery is short by transplant standards — most operations take between thirty minutes and two hours — and is usually performed under an operating microscope with the patient awake but sedated and the eye numbed.

In penetrating keratoplasty the surgeon cuts a circular disc from the centre of the diseased cornea, using a trephine, and cuts a matching disc from the donor tissue. The donor disc is placed into the opening and secured with very fine sutures, either as individual stitches or as a continuous running suture, or both. Suture tension is adjusted during surgery to reduce astigmatism, and often further adjusted at later visits.

In deep anterior lamellar keratoplasty the surgeon dissects down to just above the patient's own inner layer, frequently using an injected air bubble to separate the planes cleanly, removes the front layers and sutures donor tissue in their place. The patient's own inner cell layer stays.

In endothelial keratoplasty the approach is reversed. Through a small incision the diseased inner layer is stripped away, and the thin donor graft is introduced folded or rolled, then unfolded inside the eye. An air or gas bubble is injected to press it against the inside of the cornea, where it adheres on its own over the following hours. In DMEK, orienting the scroll the right way round is the delicate part, and the graft is marked to make that possible.

At the end, drops or an injection of antibiotic and steroid are given, and the eye is usually shielded. Endothelial patients begin their posturing immediately in recovery, and most people go home the same day.

Corneal transplantation has the best results of any transplant performed, and the reason is the immune privilege described above: an avascular cornea is largely invisible to the immune system, so grafts survive without the systemic drugs other transplants require.

Results differ sharply by why the graft was done. Keratoconus and Fuchs dystrophy — eyes that are otherwise healthy, uninflamed and free of blood vessels — do best, and grafts in these eyes commonly remain clear for many years. Eyes that are vascularised, inflamed, chemically injured or receiving a repeat graft do considerably less well, and are the eyes where matching and stronger immunosuppression are considered.

Operation type matters too. Endothelial keratoplasty gives faster visual recovery and lower rejection than full-thickness surgery, and DMEK has the best figures of all for suitable eyes. National registries — the Australian graft registry and several European ones — publish survival by indication and technique, and those breakdowns are far more useful than any single number.

A graft is not necessarily permanent. Inner cells decline steadily over years, and a graft that has worked well for a decade or more may eventually cloud. Regrafting is possible and routine, though each successive graft carries a somewhat higher risk of rejection.

Recovery differs so much between operations that a single timeline would mislead. What is common to all of them is that the eye is uncomfortable rather than painful, that vision is blurred at first in every case, and that the drops matter more than anything else you do.

After an endothelial graft, the first hours are spent lying flat and looking at the ceiling so the bubble holds the graft against the cornea. Vision immediately afterwards is very poor because the bubble itself blocks the light, and it clears as the bubble absorbs over days. Useful vision often returns within one to four weeks after DMEK, which surprises people expecting a long convalescence.

After a full-thickness graft the timeline is measured in months. Vision improves gradually as the cornea settles and sutures are adjusted, and it is not unusual for the final prescription to wait a year or more until sutures are removed. Patience is genuinely part of the treatment here, and knowing that in advance prevents a great deal of anxiety.

Drops are the constant. Steroid drops start frequently and taper over months, sometimes continuing indefinitely at low dose after endothelial grafts. Antibiotic drops cover the early period. Missing steroid drops is the commonest avoidable cause of rejection, and a written schedule with alarms is more reliable than memory.

Follow-up is frequent at first — often the next day, then at a week, a month, and progressively less — with suture removal visits continuing for a year or more after full-thickness surgery. This is the part that a patient travelling abroad has to plan for, because these visits cannot be skipped and a loose suture found late causes real damage.

Life with a corneal graft is close to ordinary life, which is what distinguishes this operation from the others on this platform. There is no systemic immunosuppression for most recipients, no dietary restriction, and no special infection precautions beyond sensible eye hygiene.

What replaces them is a small set of permanent habits. Steroid drops continue for months and, after endothelial grafts, often indefinitely at a low dose — these protect the graft and stopping them without advice is a common route to rejection. Eye pressure is checked regularly, because those same drops can raise it silently. Annual review continues for life, because a graft can fail or reject at any point.

The warning signs of corneal graft rejection are worth committing to memory, and many surgeons teach a simple mnemonic built on redness, sensitivity to light, vision loss and pain. Any of them means being seen within a day or two, not at the next routine appointment. Most rejection caught promptly is reversed completely; most rejection ignored for a week is not.

Ordinary activity returns fully. Reading, screens, exercise, travel and work are all unrestricted once healed, with the exception of protecting the eye during contact sport and hazardous work after a full-thickness graft. Swimming needs goggles for longer than people expect.

For anybody who had surgery abroad, one habit matters more than any other: make sure a local ophthalmologist has your operation note, knows which graft you had, and can see you quickly. A graft rejecting six months later does not care which country it was performed in, and the only thing that determines the outcome is how fast you are seen.

Figures shown here come from the price registry, each recorded with the source that verified it and the date it was checked. Where nothing appears, no current verified figure exists — which is more honest than an estimate written once and left to age.

Corneal transplantation is carried out in ophthalmic units with access to an eye bank, which is a much wider set of hospitals than can perform organ transplantation. Hospitals recorded on this platform are taken from public references rather than marketing claims. When comparing centres, the questions that separate them are how many grafts of your specific type they perform each year, whether they have reliable tissue supply, and what follow-up they will provide.

Corneal transplantation is the one procedure on this platform where availability genuinely varies by supply rather than by law. Because tissue is banked and can be stored, transported and imported under regulation, a country with a well-functioning donation programme can schedule surgery within weeks, while a country with a shortage may have waiting lists running to a year or more.

That gap is a legitimate reason to travel, and it is why corneal surgery abroad is a real pathway rather than a marketing proposition. Several countries with strong eye-banking systems treat international patients routinely, and some import tissue to meet demand.

The constraint on travelling is not access but continuity. Follow-up after corneal surgery is long, and suture removal after full-thickness grafting continues for a year or more. Arrange, in writing and before booking, who will see you at each stage after you return home, who holds your operation note, and what happens if a problem arises after you have flown back.