Keratoconus is a condition in which the clear front structure of the eye (the cornea) bulges outward like a cone. It is caused by the weakness in the structure of the cornea.
What Causes Keratoconus?
Tiny fibers of protein in the eye called collagen help hold the cornea in place and keep it from bulging. When these fibers become weak, they cannot hold the shape and the cornea becomes progressively more cone shaped.
Keratoconus appears to run in families. If you have it and have children, it’s a good idea to have their eyes checked for the condition starting at age 10. The condition happens more often in people with certain medical problems, including certain allergic conditions. It's possible the condition could be related to chronic eye rubbing. Most often, though, there is no eye injury or disease that can explain why the eye starts to change.
Keratoconus usually starts in the teenage years. It can, though, begin in childhood or in people up to about age 30. It's possible it can occur in people 40 and older, but that is less common.
The changes in the shape of the cornea can happen quickly or may occur over several years. The changes can stop at any time, or they can continue for decades. In most people who have keratoconus, both eyes are eventually affected, although not always to the same extent. It usually develops in one eye first and then later in the other eye.
The earliest signs of keratoconus are usually blurred vision and frequent changes in eye glass prescription, or vision that cannot be corrected with glasses. Symptoms of keratoconus generally begin in late teenage years or early twenties, but can start at any time. Other symptoms include:
- Increased light sensitivity
- Difficultly driving at night
- A halo around lights and ghosting (especially at night)
- Eye strain
- Headaches and general eye pain
- Eye irritation, excessive eye rubbing
- In the early stages, eyeglasses or soft contact lenses may be used to correct the mild nearsightedness and astigmatism caused in the early stages of keratoconus.
- Rigid gas permeable (RGP) contact lenses are generally prescribed to correct vision more adequately as the disease progresses. The contact lenses must be carefully fitted, and frequent checkups and lens changes may be needed to achieve and maintain good vision.
- Intacs, intracorneal rings, are sometimes used to improve contact lens fit.
- Corneal crosslinking is a new treatment option to halt the progression of keratoconus.
- A corneal transplant may be needed due to scarring, extreme thinning or contact lens intolerance. This is a surgical procedure that replaces the keratoconus cornea with healthy donor tissue.