Corneal transplant (or graft) is a procedure in which a donor cornea is used to replace either the full thickness or partial thickness of your damaged cornea. The cornea (clear front surface of the eye) is an essential structure for focusing the light that enters the eye. It can become damaged through eye diseases such as keratoconus and Fuch’s corneal dystrophy. It can also become damaged through trauma, such as burns or penetrating injuries.
How does corneal transplantation work?
Grafts may be full thickness or partial thickness, depending on a number of fact of factors including the surgeon’s preference and which part of your cornea is damaged. In a full thickness graft, a small disc of tissue is removed from your cornea and another disc of tissue (called the donor button), is sutured into place. The donor button comes from a donor cornea via the organ donation program. Alternatively, you may have a partial thickness graft.
Is corneal transplant the best treatment for keratoconus?
Corneal graft is often presented as the ultimate treatment for keratoconus, but in reality it should be your last resort.
Every year, The Australian Corneal Graft Registry publishes the survival rates of corneal transplants. It is interesting to note that 50% of corneal transplants will fail within fifteen years. What is also apparent is that subsequent transplants do not last as long as previous transplants – usually only half as long. This is due to your immune system having been primed by the first graft – it reacts faster to the next one.
So, if you are 20 having your first corneal graft, and it is rejected 15 years later as the figures show, you will only be in your mid 30s having your second graft. By the time you have your 4th graft it may only last a couple of years.
So, what’s the alternative?
Properly fitting contact lenses can provide functional vision without the downside of transplantation. This option should ALWAYS be fully exhausted before going down the corneal transplant route.
Even if you have failed in contact lenses in the past, this doesn’t mean you should throw in the towel. Most contact lens practitioners just don’t have the exposure to keratoconus patients day in day out, to build up their experience and achieve high success rates with these difficult to fit lenses.
It is common that a patient coming to our advanced contact lens practice for the first time will have been passed around from one ophthalmologist to another without ever having seen an expert contact lens practitioner – one who specialises in keratoconus.
There are lots of different contact lens designs to choose from: apart from the most commonly fitted hard lenses there are also hybrid lenses (which have a hard centre with a comfortable soft ‘skirt’ at the edge), scleral lenses (which vault the cornea and bear on the less sensitive white of the eye) and even piggy-back lenses (where a hard lens sits on top of a soft lens to improve comfort). Managing any underlying allergy or inflammation can also lead to successful contact lens wear and this is another area of focus at our practice.
In terms of achieving clear vision, comfortable, safe, hard contact lens wear is the best possible way to manage your keratoconus and thus avoid needing a corneal graft.
Having a corneal transplantSometimes, despite your best efforts and the best possible contact lens fitting, you may not achieve functional vision and a corneal transplant is the only option. You usually need to wait for a suitable donor cornea to become available. After your transplant surgery, your vision will take several months to settle down. A running suture (as in the image, right) will stay in your cornea for about a year, when it will be removed and a further settling down period occurs. During these times, you can be measured for glasses to improve your vision, but you may need to change them frequently as the cornea continues to settle. Some eyes see very well after a corneal graft. While you may not get 20/20 vision, the first goal is often to achieve good enough vision to legally drive a car. Corneal transplant does not restore your vision to what it was before you developed your eye disease, but it can restore an eye from non-functioning to useful everyday vision. This is a common misconception: that a corneal graft will miraculously 'fix' the problem. It is not unusual to need hard contact lenses after a corneal transplant to achieve clear vision, so if you believe that transplant is an easier option than contact lenses, you could be disappointed. Donor corneas can be rejected just like other donor organs and you will usually need to use a steroid eye drop for the first few months to a year after your graft. This helps prevent rejection.
Types of corneal graft
Corneal graft or transplantation (also called keratoplasty) involves the removal of a diseased section of your cornea and the replacement with a section of donor cornea.
Full thickness corneal graft (A)
This is where the section of cornea that is replaced consists of all the layers. It is the most commonly performed type of corneal graft.
Partial thickness (lamellar) graft (B and C)
Partial thickness grafts are becoming more common as techniques improve and they have some advantages over full-thickness grafts.
At The Eye Practice, we see keratoconus patients every day. While most will end up with comfortable contact lenses, some require a corneal transplant. We work closely with Sydney's top corneal surgeons to ensure the best outcome for you.