cornea transplant

A cornea transplant is a surgical procedure to replace part of your cornea with corneal tissue from a deceased donor. Your cornea is the transparent, dome-shaped surface of your eye that accounts for a large part of your eye's focusing power.

A cornea transplant can restore vision, reduce pain and improve the appearance of a damaged or diseased cornea. A cornea transplant, also called keratoplasty, is typically performed as an outpatient procedure.

A cornea transplant is most often used to restore vision to a person who has a damaged cornea. A cornea transplant may also relieve pain or other signs and symptoms associated with diseases of the cornea.

A number of conditions can be treated with a cornea transplant, including:

• Thinning of the cornea
• Cornea scarring, caused by infection or injury
• Clouding of the cornea
• Swelling of the cornea
• Corneal ulcers, including those caused by infection
• Complications caused by previous eye surgery

Cornea transplant is a relatively safe procedure. Still, a cornea transplant does carry a small risk of serious complications, such as:

• Eye infection
• Increased risk of clouding of the eye's lens (cataracts)
• Pressure increase within the eyeball (glaucoma)
• Problems with the stitches used to secure the donor cornea
• Rejection of the donor cornea
• Swelling of the cornea

Signs and symptoms of cornea rejection
In some cases your body's immune system may mistakenly attack the donor cornea. This is called rejection, and it may require another cornea transplant.

Make an appointment with your eye doctor if you notice any signs and symptoms of rejection, such as:

• Loss of vision
• Pain
• Redness
• Sensitivity to light

Rejection occurs in about 20 percent of cornea transplants. Put another way, for every 10 people receiving cornea transplants, two people can expect to experience rejection of the donor cornea.

Before cornea transplant surgery, you will undergo:

• A thorough eye exam. Your eye doctor looks for conditions that may cause complications after surgery.
• Measurements of your eye. Your eye doctor determines what size donor cornea you need.
• A review of all medications and supplements you're taking. You may need to stop taking certain medications or supplements before or after your cornea transplant.
• Treatment for other eye problems. Unrelated eye problems, such as infection or inflammation, may reduce your chances of successful cornea transplant, so your eye doctor will work to treat those problems before your surgery.

Finding a donor cornea
Corneas used in cornea transplants come from deceased donors. Unlike with other organs, such as livers and kidneys, people needing cornea transplants generally don't have to endure long waits. That's because nearly all people can donate their corneas after they die, so more corneas are available for transplant compared with other organs.

Most people who receive a cornea transplant will have their vision at least partially restored. But what you can expect after your cornea transplant depends on the reason for your surgery and your health conditions.

Your risk of complications and cornea rejection continues for years after your cornea transplant. For this reason, expect to see your eye doctor annually. Cornea rejection can often be managed with medications.

Vision correction after surgery
Your vision may initially be worse than before your surgery as your eye adjusts to the new cornea. It may take several months for your vision to improve.

Once the outer layer of your cornea has healed — several weeks to several months after surgery — your eye doctor will work to make adjustments that can improve your vision, such as:

• Correcting unevenness in your cornea (astigmatism). The stitches that hold the donor cornea in place on your eye may cause dips and bumps in your cornea, making your vision blurry in spots. Your doctor may correct some of this by releasing some stitches and tightening others.
• Correcting vision problems. Refractive errors, such as nearsightedness and farsightedness, can be corrected with glasses, contact lenses or, in some cases, laser eye surgery

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تظهر ضرورة زراعة القرنية في الحالات الآتية:

* إذا لم يتمكن الطبيب من تصحيح النظر بصورة مرضية
* تورم القرنية المؤلم وفشل محاولات العلاج بالأدوية والعدسات اللاصقة الخاصة بذلك
* فشل القرنية الناتج عن بعض جراحات العين مثل جراحة الكتاراكت
* القرنية المخروطية ( زيادة تحدب القرنية(