Corneal Abrasion

What Is It?

A corneal abrasion is a nick, scratch or scrape of the cornea, the transparent, dome-shaped "window" that lies directly over the eye's pupil and iris.

The cornea is a dynamic structure that is made of several layers of cells and membranes. The thin top layer, called the epithelium, is composed of sensitive epithelial 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 account for only 10 percent of the thickness of the cornea, but 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 Bowman's membrane are more likely to cause permanent corneal scars, which are opaque, whitish areas in the cornea that may interfere with normal vision.

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. At other times, they may be caused by small, airborne particles, such as dust, sand or flying debris from soldering, woodworking or weed trimming. Even fingernails — your own or someone else's — can cause a corneal abrasion if they touch the unprotected surface of the eye.

Although corneal abrasions can occur in people of all ages, people at special risk of this injury include:

• Infants who scratch their eyes unintentionally because of untrimmed fingernails
  
  
• School children who play with pencils, pens and other pointed objects
  
  
• Athletes who play sports without using some form of eyewear to protect against dust, sand or an accidental scratch from another player's finger (More eye injuries occur in baseball and football than in other sports.)
  
  
• People who have hobbies or crafts that use pointed tools, such as sewing and wood carving, or that produce dust, such as woodworking and gardening
  
  
• Workers who are exposed to eye hazards on the job, especially those involved in farming or construction
  
  
• Anyone who inserts contact lenses without properly cleaning their hands and their lenses beforehand

Currently in the United States, corneal abrasions are the most common eye injury in children, affecting twice as many boys as girls between the ages of 5 and 15. In all age groups, most cases of corneal abrasion are superficial injuries that involve only the surface epithelium of the cornea. Although these abrasions can be very painful, there is usually no permanent effect on vision.

Symptoms