AtoZ Diseases

What is this condition?

Corneal abrasion is a scratch on the surface lining of the cornea ­the transparent, convex, front portion of the eye. The most common eye injury, corneal abrasion has a good prognosis if properly treated
What causes it?

Corneal abrasion usually occurs when a foreign body, such as a bit of dust or dirt, lodges under the eyelid. Even if the particle is washed out by tears, it may still injure the cornea. For instance, a tiny piece of metal that gets in the eye of a worker who neglects to wear protective eyewear quickly forms a rust ring on the cornea and abrades it. Corneal abrasions are also common in people who fall asleep wearing hard contact lenses.

A corneal scratch from a fingernail, a piece of paper, or another organic substance may cause a persistent wound. The lining doesn’t always heal properly, and recurrent corneal erosion may develop, with delayed effects that are more severe than the original injury.
What are the symptoms?

Typically, corneal abrasion causes redness, pain, increased tearing, and a sensation of something in the eye, even after the offending particle falls out. A corneal abrasion may also affect vision. Because the cornea is richly endowed with nerve endings, symptoms are more severe than the size of the injury would suggest.
How is it diagnosed?

Diagnosis is based on typical symptoms and a history of eye injury or prolonged wearing of contact lenses. The doctor will examine the eye with a penlight to reveal a foreign body on the cornea; to check for a foreign body embedded under the lid, he or she will gently turn the eyelid inside out. To confirm the diagnosis, the doctor may stain the cornea with fluorescein, a dye that makes the injured area look green when examined with a penlight.
How is it treated?

To remove a deeply embedded foreign body, the doctor uses a spadelike device after applying a topical anesthetic. To remove a rust ring on the cornea, the doctor uses an ophthalmic burr, an abrasive device. When only partial removal is possible, healing of the epithelium lifts the ring to the surface and allows complete removal the next day.

After the foreign body is removed, antibiotic eyedrops must be instilled in the affected eye every 3 to 4 hours. Applying a pressure patch prevents further corneal irritation when the person blinks, except where abrasion is caused by contact lenses.

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