Preparing for a Corneal Translant

If you are advised to undergo a corneal transplant, your ophthalmologist will tell you what is required. The transplant will be scheduled according to the condition of your eye and the availability of a donor cornea. Occasionally, a shortage of donated corneas may delay surgery.

If both your eyes need new corneas, the second transplant will not be performed until the first eye has stabilized, which may take up to a year.After surgery, you may be permitted to return home the same day, or you may be requored to stay in the hospital for a day or more.

Some Facts you may like to know:

• It is not necessary to find a cornea with a matching tissue or blood type.
• The race, gender, and eye color of the donor are not important.
• A corneal transplant won’t change your natural eye color.
• The Cornea heals slowly and improvement in vision may take a year or more.
• It is difficult to shape the new cornea perfectly. So, astigmatism (a condition where the cornea has an irregular shape, making images seem blurred or distorted) is common after a corneal transplant. However, this can be corrected.

Corneal Transplant

The Cornea is the front, outermost layer of the eye. Just as a window lets light into a room, the cornea lets light into the eye. It also focuses the light passing through it to make images.
Corneal problems can happen to anyone at any age. Sometimes due to disease, injury or infection the cornea becomes cloudy or warped.A damaged cornea, like a frosted or misshapen windowpane, distorts light as it enters the eye. This not only causes distortion in vision, it may also cause pain.
When there is on other remedy, doctors advise a corneal transplant. In this procedure an ophthalmologist surgically replaces the diseased cornea with a healthy one to restore clear vision.

What is Corneal transplant?

A transplant is the replacement of damaged or diseased tissues or organs with healthytissues or organs. In a corneal transplant, the cloudy or warped cornea is replaced with a healthy cornea. If the new cornea heals without problems, there may be tremendous improvement in vision.

The healthy corneal tissue used for transplantation is supplied by an Eye Bank. Eye banks workround the clock to collect, evaluate, and store donated corneas. The corneas are collected from human donors within hours of death. Stringent tests are done to ensure the safety of the person receiving the cornea. The Eye Bank verifies the donor’s medical history and cause of death, and performs blood tests to ensure that the deceased person did not have any contagious disease, such as AIDSor hepatitis.Since the cornea was one of the first parts of the body to be transplanted, corneal transplants remain one of the most common, and most successful, of all transplants.

How does the Eye Work?
Anything you see is an image that enters your eye in the form of light. The different parts of your eye collect this light and send a message to your brain, enabling you to see. For perfect vision all the parts of your eye need to work properly.

• The cornea is the clear, outer layer of the eye.
• The pupil is an opening that lets light enter the eye.
• The iris, the colored paart of the eye, makes the pupil larger or smaller.
• The lens bends to focus light onto the retina.
• The retina receives light that has been focused by the cornea and lens.
• A clear (vitreous) gel fills the inside of the eye, giving it shape.

Preparing The Corneal Transplant Surgery

The Corneal Transplant Surgery:

If you are taking any other medication, ask your ophthalmologist whether you should continue it. You will probably be asked not to eat or drink anything for several hours before the surgery.
Usually a local anesthesia is used for surgery, so you will be awake but feel no pain. Intravenous medications will help you relax. The nerves in your eye will be completely numbed so you will not be able to see or move your eye. Sometimes the doctor may use general anesthesia.

The Trnsplant Procedure :
For the transplant, the doctors use an operating microscope and very delicate instruments. Once the old cornea is removed, the new cornea is stitched into place. The sutures or stitches are barely visible and are not painful, althoughyou might feel some irritation or a scratching sensation for a few days.
If necessary, other procedures may be performed at the same time as your transplant. For example, a cataract may be removed and replaced with an intraocular lens(IOL). An IOL may be replaced or removed. The vitreous gel may be removed from the eye and replaced with fluid. A damaged iris may be repaired. Your ophthalmologist will advise you about them.

Some Potential Risks :
As with other surgical procedures, a corneal transplant involves some risks- most of them can be treated.

• eye infections
• failure of the donor cornea to function normally
• rejection of the donor cornea by your body
• cataract (clouding of the eye’s lens)
• glaucoma(build-up of fluid, leading to increased pressurein the eye)
• bleeding from the iris
• swelling or detachment of the retina

Rejection of a Transplant – the dander signals!
Rejection of a transplanted cornea can occur any time, but is more likely to happen in the first year after surgery. Unfortunately, rejection reduces the chance of success of any repeat corneal transplantation. However, this can be prevented by timely diagnosis and appropriate manaement.
Watch out for these dangersignals:

• Redness
• Sensitivity to light
• Vision loss
• Pain

The acronym ‘RSVP’ can help you remember these symptoms. If you notice anyof these symptoms in your operated eye, however minor they may seem and regardless of the time of day, contact us immediately. If this is not possible, visit the nearest ophthalmologist, preferble a cornea specialist.

Diabetes and The Eye

Diabetes mellitus or diabetes is characterized by increased levels of blood sugar, due to impaired production or reduced effectiveness of insulin.Patients with diabetes stand the risk of developing diabetic retinopathy due to changes in the blood vessels of the retina caused by poor glucose control. Blindness due to diabetic retinopathy is one of the leading causes of preventable blindness.

The retina is a layer at the back of the eye that senses light and sends images to the brain. In diabetic retinopathy the blood vessels in the retina become fragile and get blocked, leading to water collection (edema), lipid deposition, retina hemorrhages, and the formation of new vessels on the retina. Vision loss can occur due to the lipid and water deposition in the center of the retina (diabetic maculopathy), or due to bleeding inside the eye from new blood vessels(vitreous hemorrhage), or due to membrane formation over the retina which “pulls” on the retina (traction retina detachment).

Symptoms:
In the early stages there are no warning signs; the treatment works best in this stage if detected by a routine retina examination. In relatively advanced stages, the vision worsens gradually or suddenly, making reading or driving difficult. bleeding in the eye an lead to black spots or floaters or total blockage of vision. Persons with advanced diabetic retinopathy may find it difficult to:

• recognize faces from a distance or read bus numbers,
• read fine newsprint, bills, or low contrast text,
• write in a straight line,
• tolerate bright light or see in dim light,
• move about independently outdoors after dusk, and
• tell the time a wristwatch or read the print on an insulin syringe.

Need for early detection
The life expectancy of diabetic patients has increased with the availability of better medicines. However this means an increase in the incidence of diabetic retinopathy and its blinding complications. People with diabetic retinopathy are 25 times more likely to experience permanent vision loss than those with other sight-threatening ailments. Early detection and appropriate treatment can help prevent this. The only method of early detection is a regular and dilated retinal examination.

The recommended check-up schedule for a patient of diabetes with no diabetic retinopathy or its milder forms is:

• No or minimal retinopathy detected – once a year
• Mild to moderate non – proliferative diabetic retinopathy – between 6 to 12 months
• Moderate to severe non – proliferative diabetic retinopathy – between 3 to 6 months
• Very severe non – proliferative diabetic retinopathy- 2-3 months
• After photocoagulation – 1 to 6 months or as advised by the treating ophthalmologist.

Diabetic Retinopathy and Pregnancy
Pregnancy can increase the porogression of diabetic retinopathy. Hence pregnant woman with diabetes should have an eye examination every three months. Controlling blood sugar after the progression of diabetic retinopathy has less effect than controlling it in the initial years of the disease.