What Is It?
The cornea is the transparent, dome-shaped "window" that covers the front of the eye. A nick, scratch or scrape of the cornea is called a corneal abrasion.
Corneal abrasions are one of the most common forms of eye injury. In some cases, they are caused by the direct impact of a sharp object, such as a pencil, staple, nail or sewing pin. They also can be caused by small, airborne particles, such as dust, sand or flying debris from soldering, woodworking or weed trimming. Even fingernails can cause a corneal abrasion.
Although corneal abrasions can occur in people of all ages, people more likely to have this happen include:
The cornea has several layers of cells and membranes. The thin top layer, called the epithelium, is composed of sensitive cells that are similar to skin. Below this surface layer lies a tough, protective structure called Bowman's membrane. The epithelium and Bowman's membrane together make up only 10% of the thickness of the cornea. They are the two layers most involved in corneal abrasions. Abrasions that involve only the surface epithelium have a good chance of healing without any long-term effects. However, deeper abrasions that penetrate through the Bowman's membrane are more likely to cause permanent corneal scars. These scars are opaque, whitish areas in the cornea that may interfere with normal vision.
In the United States, corneal abrasions are the most common eye injury in children. Boys get corneal abrasions twice as often as girls between the ages of 5 and 15. Most corneal abrasions are superficial injuries that involve only the surface layer of the cornea. Although these abrasions can be very painful, they don't usually cause permanent vision problems.
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