The cornea of the eye is the clear, rounded tissue covering your pupil and iris (the colored part of the eye). The cornea is an important focusing surface, and it must be perfectly smooth and clear for you to see well.
Any disease of the cornea can cause blurred vision, and since the cornea is highly sensitive, may cause discomfort. For example, if you have ever scratched the eye, or gotten some foreign material in your eye, you know how much it can hurt and disturb your vision.
Some of the more common disorders of the cornea, other than traumatic injury, are:
This is an inherited disorder affecting about 1 in 2000 people. With this problem, there is a gradual thinning and bulging outward of the cornea, which causes progressively blurred vision. It will typically start showing up in the late teens or twenties.
There is a wide range of severity, and many people who have it don't even know it. But it can cause blurring not correctable with eyeglasses, necessitating the use of a special type of contact lens. More severe cases may require a cornea transplant or insertion of corneal rings. A promising new treatment under investigation is cross-linking, which strengthens the cornea by linking together the collagen strands that make up the bulk of the cornea.
This is also an inherited disorder, which affects women more often than men. It usually doesn't cause any problems until after age 50, and then can cause mild to severe blurring, needing a cornea transplant if the vision blurs to the point it can't be helped with eyeglasses.
Please see our section on dry eye for more information.
Q: I feel like there's something in my eye, but my friends can't find anything. Should I make an appointment to get it checked, or will it go away on its own?
A: While your eye could heal on its own, it could also develop a serious problem if unchecked. You could have a corneal abrasion – a scratched eye. Without treatment, you could develop a corneal erosion, which could lead to serious vision loss.
Q: I'm having trouble seeing – blurred vision, light sensitivity, glare, eye irritation. How do I know what's wrong?
A: Unfortunately, those symptoms reflect a number of eye conditions. You should make an appointment with us for an eye exam. Some conditions need early treatment to prevent serious permanent vision loss. Keratoconus, a condition caused by a cone-shaped cornea, is one match to those symptoms.