| Disease | Injury | Nutrition | Poison |
| Special Topic | Surgery | Symptoms | Test |
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Keratoconus |
| Definition: |
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Keratoconus is a deterioration of the fibrous structure of the cornea with gradual bulging from the normal round shape to a cone shape. This condition causes decreased visual acuity. It is frequently discovered during adolescence. |
| Causes, incidence, and risk factors: |
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The cause is unknown. Keratoconus is more common in contact lens wearers and nearsighted eyes. Some researchers believe that allergy may play a role. |
| Symptoms: |
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The earliest symptom is subtle blurring of vision not correctable with glasses. The vision is generally correctable to 20/20 with contact lenses. |
| Signs and tests: |
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Keratoconus can usually be diagnosed with slit lamp examination of the cornea. Early cases may require corneal topography, a test which involves making a stereo image which gives a topographic map of the corneal curvature. When keratoconus is advanced, the cornea may be thinner in areas and this can be measured by pachymetry. |
| Treatment: |
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Contact lenses are the primary treatment and are satisfactory treatment for most patients with keratoconus. Severe cases may require corneal transplantation. |
| Expectations (prognosis): |
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Vision can be corrected in most cases with contact lenses. Where corneal transplantation is needed, results are usually good after a long recovery period. |
| Complications: |
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Patients with keratoconus should not have laser vision correction. Corneal topography is usually done before laser vision correction to eliminate this risk. |
| Calling your health care provider: |
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Young persons whose vision cannot be corrected to 20/20 with glasses should be evaluated by an eye doctor experienced with keratoconus. |
| Prevention: |
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There are no preventive measures. Some specialists believe that patients with keratoconus should have aggressive treatment of ocular allergy and should be instructed not to rub their eyes. |
Reviewed By: Edward B. Feinberg, M.D., M.P.H., Department of Ophthalmology, Boston University School of Medicine and Harvard Medical School, Boston, MA. Review provided by VeriMed Healthcare Network.
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