Corneal Eye Diseases

Corneal Abrasion

A corneal abrasion is a scratch or cut on the cornea — the transparent, front part of the eye that covers the iris and the pupil. The cornea plays an important role in vision by helping focus light as it enters the eye. If your cornea becomes scratched, your vision can be affected or impaired.

Corneal abrasions can be caused by a variety of factors, such as:

• A small particle flying into the eye, such as dust, sawdust, or ash
• Dust, dirt or sand becoming stuck under your eyelid
• Sports injuries where the eye is involved
• Poorly fitting or dirty contact lenses
• Being poked in the eye
• Rubbing your eyes, especially if something is caught in your eye
• Certain eye conditions, such as bacterial infections
• Having surgery while under general anesthesia

Symptoms of corneal abrasion:

• Pain in the eye, which may feel worse when you open or close your eye
• The sensation that there is something in your eye
• Tearing
• Redness in the eye
• Sensitivity to light
• Blurred vision or loss of vision
• Headache

Doagnosis of Corneal Abrasion

If you experience any of the above symptoms, you should seek care from an ophthalmologist, who will perform a thorough eye examination.

Treatment for Corneal Abrasion

A minor corneal abrasion will typically heal by itself in a few days. Your ophthalmologist may use antibiotic eye drops or steroid eye drops to reduce inflammation and reduce the chance of scarring.

If you have a more severe corneal abrasion, your ophthalmologist may place a patch on your eye to reduce discomfort. You may also be given medication to reduce the pain. Wearing sunglasses may improve symptoms of a corneal abrasion while you are healing.

If you wear contact lenses, you should not wear them until the abrasion has healed and your ophthalmologist has approved the use of contact lenses.

Corneal Dystrophies

Corneal dystrophies are genetic eye disorders that relatively rare and that can result in abnormalities of the cornea. Most corneal dystrophies affect both eyes and progress slowly. They also often run in families.

Symptoms of corneal dystrophy Symptoms may vary and depend upon the type of corneal dystrophy. Some people experience no symptoms. Others may experience a build-up of material in the cornea, leading to blurred vision or loss of vision.

Some people may also experience erosion of the cornea, in which the outer layer of the cornea fails to attach to the next layer. Corneal erosion can cause mild to severe pain in the eye, sensitivity to light, and the feeling of something in the eye.

Diagnosis of corneal dystrophy If your eye doctor suspects that you have a corneal dystrophy, he will perform a thorough eye examination and ask about your family history of eye disease.

Your ophthalmologist will use a slit lamp microscope in order to examine the front portion of your eye thoroughly.

For people who have no symptoms, a routine eye exam may indicate the presence of corneal dystrophies. In some cases, genetic testing can be used to identify corneal dystrophies.

Treatment of corneal dystrophy Treatment options for corneal dystrophies depend upon the type of dystrophy and the severity of the symptoms. If you are not experiencing any symptoms, your doctor may continue to monitor your eyes closely for signs of progression. In some cases, your doctor may recommend eye drops, ointments or laser treatment.

Some people with corneal dystrophy will experience repeat corneal erosion, which may be treated with antibiotics, lubricating eye drops, ointments, or bandage contact lenses that protect the cornea. If erosion continues, your eye doctor may recommend additional treatment options such as the use of laser therapy or a technique for scraping the cornea.

In more severe cases, a cornea transplant (keratoplasty) may be necessary. During a keratoplasty, the damaged or unhealthy cornea tissue is removed and replaced with clear donor corneal tissue. For some types of corneal dystrophies, a partial corneal transplant may be necessary.

Cornea transplants can be very successful in patients with poor vision, or whose corneas have been significantly damaged from corneal dystrophies.

Cornea Transplantation

Many conditions can affect the clarity of the entire cornea. For an injury to or infection of the cornea can cause scarring. Hereditary conditions such as corneal dystrophy can impair vision. In these cases, a corneal transplant may be able to restore vision.

Surgical options for corneal transplant A corneal transplant may be needed if vision cannot be corrected satisfactorily with eyeglasses or contact lenses, or if painful swelling of the cornea cannot be relieved by medications or special contact lenses.

A corneal transplant uses a cornea from a human donor. Before a donated cornea will be released for transplant, it is checked for clarity. Tests are also conducted for viruses that cause hepatitis, AIDS and other potentially infectious diseases.

Full corneal transplant In a traditional full corneal transplant surgery (known as penetrating keratoplasty), a circular portion of the damaged cornea is removed. A matching area is removed from the center of a donor cornea and sutured into place.

EK corneal transplant With an EK cornea transplant procedure (endothelial keratoplasty), only the abnormal inner lining of the cornea is removed. A thin disc of donor tissue is placed on the back surface of the cornea. An air bubble pushes the endothelial cell layer into place, allowing it to heal in the correct position.

Lamellar corneal transplant With a lamellar corneal transplant procedure, the superficial layers of the cornea are removed and replaced with healthy donor tissue. The new tissue is sutured into place.

Which part of the eye can be transplanted? The eye is connected to the brain by the optic nerve, which sends visual signals from the eye to the brain, where they are interpreted as images. Although the optic nerve is very thin, it is made up of more than one million tiny nerve fibers. If these nerve fibers are cut, they cannot be reconnected, which is why it’s impossible to transplant a whole eye. Even if a surgeon were to implant an eye into the eye socket, the option nerve could not be reconnected and would not be able to send signals to the brain.

However, corneal transplantation is a viable option for many people with impaired vision. Good vision requires a healthy, clear cornea. If your cornea is injured or affected by disease, it may become swollen or scarred. A cornea that has been damaged by scarring or swelling, or one that is irregularly shaped, can cause glare or blurred vision. Through a corneal transplant, damaged or unhealthy corneal tissue is removed and replaced with clear donor corneal tissue.

Corneal transplants are not the only type of eye-related transplantation. Patients who suffer from disorders of the sclera or the conjunctiva (the external eye), may be able to undergo a transplant of amniotic membranes, which can aid in the healing and regeneration of ocular surface tissues.

Doctors continue to explore new procedures for transplanting other parts of the eye. In 2010, doctors in France transplanted eyelids and tear ducts as part of a full-face transplant for a man with a genetic disorder. Researchers are also focusing on how to replace damaged retinal cells with healthy transplants, which is good news for people suffering from macular degeneration.

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A Generous Gift of Sight

Corneal transplant would not be possible without the thousands of generous donors and their families who have donated corneal tissue so that others may see. Each year, nearly 50,000 people with corneal disease are given the gift of sight through cornea donors.
Source: Eye health information from the American Academy of Ophthalmology