Keratoconus is caused by a decrease in protective antioxidants in the cornea. If the antioxidant levels are low, collagen and weakens the cornea protrudes. We see through the cornea, the transparent outer lens of the eye. Normally, the cornea has a dome shape and is round like a ball. Sometimes, however, the structure of the cornea is not only strong enough to hold this round shape and cornea bulges outward. Small protein fibers in the eye called collagen helps keep the cornea in place and minimize pressure. When these fibers become weak, they can not maintain the shape and the cornea becomes increasingly shaped like a cone.
Keratoconus changes the vision of two ways:
* The smooth surface over the eye becomes wavy as the cornea changes shape. This is known as an irregular astigmatism.
* Vision becomes more nearsighted as the front of the cornea is expanded and anything too far will be blurry.
Symptoms for keratoconus include the following:
- Sudden change of vision in one eye
- Double vision or “ghost images”
- Distorted vision, with objects both near and far
- Lights with halos or streaks
- Blurred vision while driving
Keratoconus usually begins in adolescence and seems to run in families. The disease progresses more rapidly in people with certain medical problems, most commonly in people with allergies or other conditions that lead to chronic eye rubbing.
The cornea can change shape relatively quickly or may occur over several years. These changes can lead to blurred vision or a constant glare. Changes can also stop quickly or continue for decades. There is no way to predict how the condition will progress. In most cases, both eyes are eventually affected, although not always to the same extent.
Treatment usually starts with new glasses. If the lenses do not provide adequate vision, then contact lenses can be recommended. With severe keratoconus, stretched collagen fibers can lead to swelling and scarring. A cornea transplant is sometimes necessary to restore vision if the condition is very severe. There are also specialized treatments that can be done to prevent the progression of the disease or help with recovery after a cornea transplant.
Vision correction laser surgery –LASIK – is dangerous for people with keratoconus, as it may further weaken the cornea and make the vision worse. Anyone with even a small degree of keratoconus should not have LASIK surgery.