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What is keratoconus? | Symptoms | Causes | Treatment | Consequences

What is keratoconus?

The cornea is normally round. However, sometimes the middle of the cornea thins and bulges out forming a cone shape. This condition is called keratoconus. Light can't focus on the retina, so the person has blurred vision. Keratoconus usually occurs during puberty or soon thereafter. As the disease progresses, the cornea will bulge more and vision will become increasingly distorted. In a few cases, the cornea will swell and cause a significant decrease in vision. The swelling happens because a tiny crack occurs from the strain of the protruding cone-like shape. The swelling may last for weeks or months as the crack heals, but it is gradually replaced by scar tissue.

The ophthalmologist can prescribe eye drops for temporary relief from pain, but the medication can't stop the progress of the disease or the formation of the scar. Keratoconus usually stabilizes after a few years.

Symptoms

In the early stages, symptoms include a slight blurring of vision and an increased sensitivity to glare. Keratoconus usually appears in late teens or twienties. It progresses for ten to twenty years and then slows its progress.

If you are experiencing some of the symptoms described here, it does not necessarily mean you have keratoconus. However, if you experience one or more of these symptoms, you should contact your eye doctor for a complete exam. Click here for information on emergency or immediate care.

Causes

Keratoconus can be inherited. Seven percent of the patients have a family history of keratoconus. Eye injuries resulting from excessive eye rubbing or wearing hard contacts for a number of years can also cause it. Keratoconus can also be a complication of certain eye diseases including retinitis pigmentosa, retinopathy of prematurity, and vernal keratoconjunctivitis. Keratoconus can also develop as a complication of other systemic diseases such as Leber's congenital amaurosis, Ehlers-Danlos Syndrome, Down's Syndrome, osteogenesis imperfecta, and Addison's Disease.

Treatment

In the early stages of the disease, patients can use eyeglasses or contacts to correct nearsightedness or astigmatism. As the cornea continues to thin, rigid gas-permeable contacts may be used. They need to be carefully fitted and the patient will need frequent checkups and lens changes.

Consequences

Complications of keratoconus include infection, bleeding, swelling, detachment of the retina, and glaucoma. If the cornea becomes too scarred or won't tolerate a contact lens, the patient may need a corneal transplant. Most likely, patients will still need glasses or contacts to their correct vision.