Progressive change in the shape of the cornea, the transparent front part of the eye, causing blurred vision

  • Usually develops around puberty
  • Sometimes runs in families; more common in people of Asian descent.
  • Gender and lifestyle are not significant factors

In keratoconus, the central area of the transparent cornea that forms the front of the eye grows abnormally, becoming cone-shaped and thin. Also known as conical cornea, keratoconus is a rare condition that is sometimes inherited and is more common in people of Asian descent. It usually begins at puberty and may affect one or both eyes. As the shape of the cornea changes, astigmatism develops and vision becomes blurred. As the distortion of the cornea progresses, symptoms worsen, in some cases quite rapidly.

What might be done?

A slit lamp may be used to examine your eyes (see Slit-lamp examination), and the shape of your corneas may be measured using a technique called corneal topography. If keratoconus is detected in its early stages, your vision can be corrected by glasses or hard contact lenses (see Glasses and contact lenses). However, if your vision has seriously deteriorated, your doctor may suggest a corneal graft, an operation in which the abnormal cornea is replaced with a healthy one from a donor. This operation will usually restore normal vision permanently.

Effects of keratoconus

The normal cornea has an even, spherical curvature. Keratoconus causes the cornea to grow abnormally, becoming thinner and bulging forwards in a conical shape.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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