is caused by weakness of the corneal tissues, which leads to its gradual change in shape. The central part of the cornea becomes thinner than normal and the cornea takes on the shape of a cone rather than that of a sphere. The first signs of the disease usually appear in young adults, sometimes in more than one member of the family.
The basic cause of the condition is unknown but frequent rubbing of the eyes in patients with allergic conditions may be a contributing factor, or make the existing condition worse. It may affect one or both eyes. In the early stages of the condition the patient has to change his spectacles due to the development of short sight and astigmatism. If there is a suspicion of keratoconus the diagnosis can be confirmed by photographically mapping the corneal curvature (topography).
Treatment. In mild keratoconus the vision can be improved with spectacles. If the condition progresses contact lenses may be required, including special keratoconus lenses. More advanced cases may be treatable by implanting a ring made of a special plastic into the cornea in order to support the cornea. Eventually the cornea may become very thin and develop opacities in its center, making surgery unavoidable. The operation consists of replacing some or all of the corneal layers with a transplant taken from the cornea of recently deceased person, after performing certain examinations to make sure that the donor cornea is suitable and cannot transfer any disease to the recipient.
A new form of treatment called “cross linking”
may be suitable for certain cases of keratoconus: chemical treatment and radiation of the cornea strengthens the tissue in the hope of preventing progression of the disease.