Dr. Lisa M. Nijm, J.D., with Clinic's Eye Institute in Springfield, Ill., provides the answers on what you might not know about your eye's cornea in this Q-and-A.
Q. What is the cornea?
A. The cornea is truly the "window” of the eye. It is a transparent dome-shaped structure that covers the front of the eye.
An easy way to locate the cornea is simply to look at your eye in the mirror. You will notice a clear surface covering the iris (the colored part of the eye) and the pupil –– this is your cornea. The cornea is approximately .5 millimeters thick and is composed of five distinct layers of cells.
Q. What is the function of the cornea?
A. The cornea has two important functions that are key to good vision.
First, it provides almost two-thirds of the refracting power of the eye. Along with the lens inside the eye, the cornea bends the light rays coming into the eye to sharply focus them on the retina (in the back of the eye) to produce a clear image.
In addition, the cornea also serves as an important barrier that protects the inside of the eye from germs, dust and other harmful material. Injury to the cornea can allow bacteria and other pathogens to cause an infection inside the eye.
Q. How does the cornea cope with injury?
A. The cornea copes very well with minor injuries that affect the superficial layers of cells. In healthy corneas, when one has a "scratch" to the cornea, called a corneal abrasion, healthy cells will usually slide over and patch the injury before infection occurs.
However, if the scratch is deeper, the healing process will take longer and may result in greater pain, blurred vision, redness, tearing and sensitivity to light. Further, injuries to the deeper layers of the cornea may result in scarring that affects vision. Permanent scarring of the cornea may require a corneal transplant to improve vision.
Q. What are some diseases and disorders affecting the cornea?
A. By far, the most common disorder affecting the cornea is refractive error (e.g. nearsightedness, farsightedness or astigmatism). Approximately 120 million people in the United States wear eyeglasses or contact lenses to correct refractive errors.
These vision disorders often occur because the curve of the cornea is too steep or too flat, thus affecting the ability of the cornea to focus the light on the back of the eye.
LASIK surgery can be performed to change the shape of the cornea to correct these types of vision problems. Other diseases that affect the cornea include infection, dry eyes, allergies, shingles, Fuchs dystrophy, keratoconus (thinning disorder of the cornea) and inherited disorders.
Q. How can you keep the cornea healthy?
A. Proper eye protection and adequate lubrication of the cornea as we age are keys for keeping the cornea healthy. If you wear contact lenses, it is important to follow good contact lens hygiene to decrease your risk of corneal infections.
Q. What else would you like to add when it comes to the cornea?
A.As we are approaching summer, it is important to remember not only to protect your corneas but also protect your eyes from injuries at all times.
Almost half of all eye injuries occur at home and, therefore, it is important to think ahead and use eye protection whenever possible. Especially in situations where you are working with metal, wood or bleach, or playing sports like baseball, hockey, paintball or racquet sports. Remember, eyeglasses alone may not be sufficient to protect your eyes from flying debris and projectiles.
Where to go for more information?
The American Academy of Ophthalmology, http://www.geteyesmart.org, has a great website for patients that provides information on the cornea as well as other diseases of the eye.
Dr. Lisa M. Nijm, J.D., is with The Eye Institute at the Springfield (Ill.) Clinic. Her specialties are ophthalmology, cataract surgery, cornea and external disease and refractive surgery and LASIK surgery.
-- From BeHealthySpringfield.com
Q. What is the cornea?
A. The cornea is truly the "window” of the eye. It is a transparent dome-shaped structure that covers the front of the eye.
An easy way to locate the cornea is simply to look at your eye in the mirror. You will notice a clear surface covering the iris (the colored part of the eye) and the pupil –– this is your cornea. The cornea is approximately .5 millimeters thick and is composed of five distinct layers of cells.
Q. What is the function of the cornea?
A. The cornea has two important functions that are key to good vision.
First, it provides almost two-thirds of the refracting power of the eye. Along with the lens inside the eye, the cornea bends the light rays coming into the eye to sharply focus them on the retina (in the back of the eye) to produce a clear image.
In addition, the cornea also serves as an important barrier that protects the inside of the eye from germs, dust and other harmful material. Injury to the cornea can allow bacteria and other pathogens to cause an infection inside the eye.
Q. How does the cornea cope with injury?
A. The cornea copes very well with minor injuries that affect the superficial layers of cells. In healthy corneas, when one has a "scratch" to the cornea, called a corneal abrasion, healthy cells will usually slide over and patch the injury before infection occurs.
However, if the scratch is deeper, the healing process will take longer and may result in greater pain, blurred vision, redness, tearing and sensitivity to light. Further, injuries to the deeper layers of the cornea may result in scarring that affects vision. Permanent scarring of the cornea may require a corneal transplant to improve vision.
Q. What are some diseases and disorders affecting the cornea?
A. By far, the most common disorder affecting the cornea is refractive error (e.g. nearsightedness, farsightedness or astigmatism). Approximately 120 million people in the United States wear eyeglasses or contact lenses to correct refractive errors.
These vision disorders often occur because the curve of the cornea is too steep or too flat, thus affecting the ability of the cornea to focus the light on the back of the eye.
LASIK surgery can be performed to change the shape of the cornea to correct these types of vision problems. Other diseases that affect the cornea include infection, dry eyes, allergies, shingles, Fuchs dystrophy, keratoconus (thinning disorder of the cornea) and inherited disorders.
Q. How can you keep the cornea healthy?
A. Proper eye protection and adequate lubrication of the cornea as we age are keys for keeping the cornea healthy. If you wear contact lenses, it is important to follow good contact lens hygiene to decrease your risk of corneal infections.
Q. What else would you like to add when it comes to the cornea?
A.As we are approaching summer, it is important to remember not only to protect your corneas but also protect your eyes from injuries at all times.
Almost half of all eye injuries occur at home and, therefore, it is important to think ahead and use eye protection whenever possible. Especially in situations where you are working with metal, wood or bleach, or playing sports like baseball, hockey, paintball or racquet sports. Remember, eyeglasses alone may not be sufficient to protect your eyes from flying debris and projectiles.
Where to go for more information?
The American Academy of Ophthalmology, http://www.geteyesmart.org, has a great website for patients that provides information on the cornea as well as other diseases of the eye.
Dr. Lisa M. Nijm, J.D., is with The Eye Institute at the Springfield (Ill.) Clinic. Her specialties are ophthalmology, cataract surgery, cornea and external disease and refractive surgery and LASIK surgery.
-- From BeHealthySpringfield.com
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