A diagram showing cross section of the eye with different parts labelled

Keratoconus (keh-rah-toe-cone-us) affects your cornea, the clear dome-shaped window at the front of your eye. Your cornea focuses light into your eye to help produce a clear image.

In keratoconus, your cornea becomes weaker and thinner at its centre. This thinning causes it to bulge outwards in an irregular cone shape. This can make your vision blurry and distorted, as light being focused by your cornea forms an unclear image on your retina, at the back of your eye.

Keratoconus usually develops in your teens or 20s and can worsen over time. It cannot be treated with eye drops or other medications. In the early stages, glasses may help correct vision. As keratoconus develops glasses may no longer help, but most people can still get a good level of vision by wearing contact lenses. Depending on your keratoconus sometimes contact lens can be uncomfortable to wear for long periods. 

Some treatments are becoming available which can prevent sight being more affected or try to improve the shape of the cornea to give a better level of vision. A treatment called collagen cross-linking can help to slow down the development of keratoconus, to prevent further changes to the cornea. This can mean that someone can continue to get a good level of sight with glasses or contact lenses. Corneal implants can also be used to try and improve the shape of the cornea to give better vision with contact lenses.

For some people keratoconus can continue to worsen to a stage where contact lenses no longer give clear vision. If this happens, it is possible to have a corneal transplant, which can improve sight to a good level again.

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