Corneal Transplant Surgery
What is the cornea?The cornea is the clear window at the front of the eye in front of the coloured iris and the round pupil. Light is focused when it passes through the cornea. In order to see clearly, the cornea must be smooth and clear.
What is a corneal transplant operation?In this operation, a diseased, cloudy or irregular cornea is removed and replaced with a new, clear cornea. Of all transplant surgery performed today, including heart and kidney transplants, corneal transplants are by far the most common and the most successful.
How can an unhealthy cornea affect vision?Damage to the cornea may result in it becoming scarred, swollen or distorted. This may cause the cornea to scatter or distort light rather than focus it. The result is blurred vision or glare.
A corneal transplant may be required if:
- Vision cannot be corrected satisfactorily with glasses or contact lenses
- Painful swelling cannot be relieved with medications or special ‘bandage’ contact lenses
What conditions may require a corneal transplant?
- Keratoconus – In this condition, instead of the cornea having a smooth rounded surface, it becomes pointed like a cone – hence the name keratoconus
- Corneal failure after previous eye surgery such as cataract surgery
- Inherited conditions leading to clouding of the cornea
- Scarring after infections, especially herpes eye infections
- Scarring after injuries
- Rejection after a previous corneal transplant
How is a corneal transplant operation performed?The surgery is usually performed under a general anaesthetic, but can be performed under a local anaesthetic if your general health is poor. Using a surgical microscope your ophthalmologist will remove a central disc from the diseased cornea. If additional work inside the eye is required, such as removal of a cataract, this is then carried out. The clear donor cornea is then sewn into place with some stitches. When the operation is over, a plastic shield will be placed over the eye to protect it.
What checks are made on the donor cornea prior to surgery?At the eye bank the donor cornea is carefully tested for infections such as hepatitis and AIDS. No cornea is released from the eye bank if there is any suspicion of these diseases. It is then checked for clarity and the number and health of the cells on the back surface of the cornea is determined. These cells are very important for the health of the transplanted cornea.
Your ophthalmologist is informed of the results of all these tests before the operation and will make a decision on whether or not to accept the graft material.
After the operationIf your surgery is being done as an outpatient you may go home after a short stay in recovery. Some patients will need to stay in hospital overnight. You will need someone to drive you home and to stay with you on at least the first night after the operation. An examination will be scheduled for the following day.
You will need to:
- Use the eye drops as prescribed
- Use over the counter pain medication if necessary – Paracetamol or Codeine may be used but Aspirin should be avoided
- Be careful not to rub or press on the eye – if the eye waters, gently dab it with a tissue
- Wear eye glasses or protective glasses during the day and the eye shield at night for the first 6 weeks
- Continue normal daily activities except strenuous exercise
- Avoid situations where you may accidentally receive a knock to the eye
- Ask Dr Hornsby when you can begin driving and return to work – most people can return to work between 2 and 4 weeks after their operation
How long will my vision take to recover?Unlike cataract surgery, the eye will take quite a long time to recover. It may well take up to a year before you know what the final vision will be like. During this period, it may be necessary to remove some or all of your stitches. Some patients will need an adjustment to their glasses, whilst others will need to wear a contact lens to achieve the best vision.
How long will I have to use my drops?You will have to use drops in the operated eye for up to a year. To begin with you will have to use the drops frequently. The frequency then gradually reduces until you can stop the drops at about a year.
How successful is the operation?This depends on the condition for which you are having the operation. The condition with the highest success rate is keratoconus. The five year success for corneal grafting for keratoconus is in the order of 90-95%. Dr Hornsby will talk to you about the likely success rate in your individual case.
What are the main complications?It is important to remember that, like any operation, problems may occasionally occur. If local anaesthesia is used there may be occasional problems related to the local anaesthetic injection given before surgery. These can include bruising around or inside the eye. The possible complications related to general anaesthetic depend on your state of health. Please discuss these with your anaesthetist. He or she will help you decide which form of anaesthesia is best for you.
Infection, bleeding, glaucoma and swelling or detachment of the retina are some of the more serious complications that may affect your vision. There is about one chance in one thousand of a serious complication which may require special treatment or result in loss of part or all of the vision.
A very rare complication is sympathetic ophthalmia. Here an immune reaction develops that can cause loss of vision in both eyes. The incidence of this condition is less than one in fifty thousand. This rare condition can usually be successfully treated with medications.
What is the risk of rejection?Corneal transplants reject 5% to 30% of the time. The body recognises that the new cornea is foreign and causes inflammation and clouding of the graft. You may notice that the vision becomes blurred and the eye red and painful.
If this happens any time after the operation you should contact Dr Hornsby as soon as possible. In most instances, rejection can be successfully treated, if treatment is started early. The treatment involves putting eye drops in the eye very frequently. Tablets may also be prescribed.
What is astigmatism?Irregularity of the surface of the graft may result in blurred vision. Sometimes this can be corrected by selectively removing some of the stitches. Appropriate glasses, contact lenses or further surgery may be needed in some cases.
Pre-existing conditionsAny pre-existing eye conditions such as macular degeneration, glaucoma or diabetic retinopathy may limit the vision after surgery, even if the corneal graft surgery is successful. However, even with such problems, corneal graft surgery may still be worthwhile. Dr Hornsby will discuss these factors with you.
Can a corneal graft be repeated?A corneal graft can be repeated if necessary, usually with your good results. The rejection rate for repeat grafts however is high than for first time grafts.
ConclusionA successful corneal transplant requires care and attention on the part of both the doctor and the patient. The vast majority of patients who undergo corneal transplants are happy with their improved vision.
Of course, corneal transplants would not be possible without the generosity of donors and their families. Their gift allows others to see.
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AddressSuite 15, Mater Medical Centre
76 Willetts Road
Mackay QLD 4740