Navigate Up

Seniors Center - A-Z Index

#
Q
Y
Z

Print This Page

Keratoconus

Keratoconus is an eye disease that affects the structure of the cornea. The cornea is the clear tissue covering the front of the eye.

The shape of the cornea slowly changes from the normal round shape to a cone shape. The eye bulges out. This causes vision problems.

Causes, incidence, and risk factors

The cause is unknown, but the tendency to develop keratoconus is probably present from birth. Keratoconus is thought to involve a defect in collagen, the tissue that provides strength to the cornea and gives it it's shape.

Some researchers believe that allergy and eye rubbing may play speed up damage.

There is a link between keratoconus and Down syndrome .

Symptoms

The earliest symptom is subtle blurring of vision that cannot be corrected with glasses. (Vision can most often be corrected to 20/20 with rigid, gas-permeable contact lenses.) Over time, you may have eye halos, glare, or other night vision problems.  

Most people who develop keratoconus have a history of being nearsighted . The nearsightedness tends to become worse over time. As the problem gets worse, astigmatism develops.

Signs and tests

Keratoconus is often discovered during adolescence. The most accurate test is called corneal topography, which creates a map of the curve of the cornea.

A slit-lamp examination of the cornea can diagnose the disease in the later stages.   

A test called pachymetry can be used to measure the thickness of the cornea.

Treatment

Contact lenses are the main treatment for most patients with keratoconus. Wearing sunglasses outdoors after being diagnosedmay help slow or prevent the disease from becoming worse. For many years, the only surgical treatment has been corneal transplantation .

The following newer technologies may delay or prevent the need for corneal transplantation:

  • High-frequency radio energy (conductive keratoplasty) to change the shape of the cornea so contact lenses work better
  • Corneal implants called intracorneal ring segments to change the shape of the cornea so contact lenses work better
  • An experimental treatment called corneal cross-linking causes the cornea to become hard and stops the condition from getting worse. The cornea can then be reshaped with laser vision correction.

Expectations (prognosis)

In most cases vision can be corrected with rigid gas-permeable contact lenses.

If corneal transplantation is needed, results are usually good. The recovery period can be long, and patients often still need contact lenses.

Complications

There is a risk of rejection after corneal transplantation, but the risk is much lower than with other organ transplants.

Patients with even borderline keratoconus should not have LASIK, the most common type of laser vision correction. Corneal topography is done before laser vision correction to rule out people with this condition.

In rare cases of mild keratoconus, other laser vision correction procedures may be safe to use, such as PRK. For patients treated with CK or CXL, PRK may be safe to perform and may help to further improve the vision.

Calling your health care provider

Young persons whose vision cannot be corrected to 20/20 with glasses should be evaluated by an eye doctor experienced with keratoconus. Parents with keratoconus should consider having their child or children screened for the disease starting at age 10.

Prevention

There are no preventive measures. Some specialists believe that patients with keratoconus should have their eye allergies aggressively treated and should be instructed not to rub their eyes.

References

Jain A, Paulus YM, Cockerham GC, Kenyon KR. Keratoconus and other noninflammatory corneal thinning disorders. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 19th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2009:chap 16C.

Sugar J, Wadia HP. Keratoconus and other ectasias. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2008:chap 4.18.

Dahl BJ, Spotts E, Truong JQ. Corneal collagen cross-linking: an introduction and literature review. Optometry. 2012 Jan;83(1):33-42.

Updated: 9/18/2012

David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc. Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, California; Brian S. Boxer Wachler, MD, Opthamologist, Boxler Wachler Vision Institute, Beverly Hills, California.


©  UPMC | Affiliated with the University of Pittsburgh Schools of the Health Sciences
Supplemental content provided by A.D.A.M. Health Solutions. All rights reserved.

For help in finding a doctor or health service that suits your needs, call the UPMC Referral Service at 412-647-UPMC (8762) or 1-800-533-UPMC (8762). Select option 1.

UPMC is an equal opportunity employer. UPMC policy prohibits discrimination or harassment on the basis of race, color, religion, ancestry, national origin, age, sex, genetics, sexual orientation, marital status, familial status, disability, veteran status, or any other legally protected group status. Further, UPMC will continue to support and promote equal employment opportunity, human dignity, and racial, ethnic, and cultural diversity. This policy applies to admissions, employment, and access to and treatment in UPMC programs and activities. This commitment is made by UPMC in accordance with federal, state, and/or local laws and regulations.

Medical information made available on UPMC.com is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have. Further, UPMC.com is not a tool to be used in the case of an emergency. If an emergency arises, you should seek appropriate emergency medical services.

For UPMC Mercy Patients: As a Catholic hospital, UPMC Mercy abides by the Ethical and Religious Directives for Catholic Health Care Services, as determined by the United States Conference of Catholic Bishops. As such, UPMC Mercy neither endorses nor provides medical practices and/or procedures that contradict the moral teachings of the Roman Catholic Church.

© UPMC
Pittsburgh, PA, USA UPMC.com