Keratoconus
Keratoconus is a vision disorder that occurs when the normally round cornea (the front part of the eye) becomes thin and irregular shaped. This abnormal shape prevents the light from entering the eye from being focused correctly on the retina and causes distortion of vision.
Eyeglasses or soft contact lenses may be used to correct the mild nearsightedness and astigmatism that is caused by the early stages for keratoconus. As the disorder progresses and cornea continues to thin and change shape, rigid gas permeable contact lenses can be prescribed to correct vision adequately. In most cases, this is adequate. The contact lenses must be carefully fitted and frequent checkups and lens changes may be needed to achieve and maintain good vision.
In a few cases, a corneal transplant is necessary. However, even after a corneal transplant, eyeglasses or contact lenses are often still needed to correct vision.