Written by: The Complete Guide To Corneal Transplants, Published: 02 September 2019
A corneal transplant is a surgical procedure in which all or part of a damaged cornea is replaced with a healthy one, from the eye of a donor. It is also known as keratoplasty or corneal graft.
There are three types of corneal transplant; determined by which part of the cornea is damaged.
Read on to learn about these different types of corneal transplants and when they are needed.
Put simply, the cornea is the outermost layer of the eye; that is clear and dome-shaped. The cornea works hard to fulfil two main functions. Firstly it acts as a protective barrier against dirt and germs that can enter the eye - without this our eyes would be vulnerable to nasty infections.
Secondly, it acts as a clear lens that controls and focuses light rays that enter the eye and allow us to see in focus. In fact, the cornea contributes to around 70% of the eye's total focusing power.
Contrary to popular belief, the cornea is not made up of blood vessels, but of cells and proteins. Blood vessels would cloud the cornea and stop it from refracting light correctly.
So there you have it! The cornea is an integral part of keeping the eyes healthy. Now let’s explore what happens when damage is made, due to conditions and infection...
A corneal transplant will be required if an individual has a severe infection, damage or disease in the cornea.
Common reasons for requiring a corneal transplant include:
Keratoconus is a common eye condition, affecting up to one in 3000 people. When keratoconus begins to develop, the cornea starts to thin and weaken, which causes it to expand into a cone like shape.
Keratoconus occurs due to a lack of antioxidants that are needed to protect the collagen in the cornea; therefore having difficulty holding its natural dome shape.
Although there is no specific cause, it is said to be more prevalent in people with multiple allergic conditions, such as eczema and asthma; as well as those with a family history of the condition.
Keratoconus generally appears during adolescence, with most cases being so mild it can be controlled using contact lenses or glasses. However in more extreme circumstances, the condition may progress to the point where a corneal transplant is required.
Certain conditions that affect the eyes, such as Fuchs' Endothelial Dystrophy, cause the inner most lining of the cornea to deteriorate. This will cause a clouding of vision which can be rectified with a corneal transplant.
If antibiotics are unsuccessful in treating a cornea infection or infection is recurring, a corneal transplant will be needed as a last resort treatment.
Similarly corneal transplantation will be recommended if the cornea is scarred as a result of an infection or injury.
The type of corneal transplant needed will depend on the degree of damage the cornea has experienced and thus how much of the cornea needs replacing. The three types of surgery are:
During this procedure, all layers of the damaged cornea are carefully removed from the center of the eye and replaced with a donated cornea. This type of corneal transplant is suitable for those who have a high degree of cornea damage.
The new cornea is attached with small stitches; anaesthetic is applied prior to surgery so no pain should be felt.
The procedure generally takes less than an hour from start to finish with most people needing to stay in hospital overnight to rest and recover.
Partial thickness corneal transplants differ from full-thickness because the innermost layer of cornea is not removed. Instead the surgeon will inject air into the eye to lift the outer and middle layers of your cornea. The healing time is therefore shorter.
People with keratoconus or corneal scarring are most suitable for this procedure.
Around 50% of all corneal transplants are carried out by endothelial keratoplasty. During this procedure the surgeon will remove and replace only the endothelium – the very outermost layer of the cornea, which is only one cell thick.
This type of corneal transplant does not require stitches. The donated cornea is held in place by an air bubble for a few days until it naturally sticks to a deeper layer of the cornea.
The procedure takes around 45 minutes and an over-night stay is not usually needed.
After any procedure, it’s important to follow the aftercare guidelines given to you by your surgeon. This is to ensure a speedy and safe recovery and reduce the risk of infection. The majority of patients will be able to return to work after 2-3 weeks post-surgery.
After a corneal transplant, remember to: