eye health conditions

cataract | computer vision syndrome | diabetic retinopathy | dry eye
glaucoma | keratoconus | macular degeneration

Keratoconus

Keratoconus is a disorder of the human eye where the normally round shape of the cornea becomes distorted and a cone-like bulge develops. Keratoconus generally progresses slowly and can stop at any stage from mild to severe. As the disorder progresses, the cornea becomes thin and bulges and can sometimes create scars on the cornea. Keratoconus rarely causes blindness but can significantly interfere with vision.

What are the causes of keratoconus?

The causes of keratoconus are still unknown. It may be a consequence of an abnormality of growth, part of a larger disease process, or hereditary. Keratoconus usually shows up in the late teen years to the early twenties.

Keratoconus is found in all parts of the world, in all cultures and races. An estimated 1 in 2,000 people have keratoconus.

What are the symptoms of keratoconus?

The first symptoms of keratoconus are usually blurred or distorted vision. At first, the vision can be easily corrected with eyeglasses. As keratoconus progresses, the person's vision becomes more and more nearsighted. Vision irregularity and astigmatism will develop.

Once a person reaches a moderate degree of keratoconus, contact lenses will be necessary to correct vision. In severe cases, scarring will form and corneal transplantation may be discussed.

How is keratoconus treated?

• Contact Lenses

  The type of contact lens used to correct the vision of most people with keratoconus is called a rigid gas permeable (RGP) contact lens. RGP lenses are able to correct the degree of nearsightedness and astigmatism associated with keratoconus. These type of lenses also provide the cornea with best supply of oxygen.

The specialized and customized fitting of the contact lens to the "cone" can be difficult. A great deal of expertise must be used and frequent check-ups are vital in the successful wearing of these lenses. The process requires a great deal of skill and patience on the part of the doctor and patient.

When fit properly, RGP contact lenses offer people from all walks of life the potential for enjoyable vision for work and play. These contact lenses provide significant improvement in vision but it is important to remember that the lenses do not cure or otherwise affect the disease.

• Corneal Transplantation

  Up to 20% of people with keratoconus might need a corneal transplant to restore vision. During this outpatient operation, the diseased cornea is removed and is replaced with a donated cornea.

The success rate for corneal transplantation is approximately 95% but can be associated with significant risks, including rejection and unstable vision. Medication eye drops can usually control most complications and frequent checkups are important for the first year until the eye is fully healed. However, because of the potentially serious complications, only people with severe keratoconus are considered for transplantation.

For more information on keratoconus, call Dr. Ni at 650.947.3937 or visit the National Keratoconus Foundation's website at www.nkcf.org.