keratoconus /ker′ətōkō″nəs/ [Gk, keras + konos, cone] , a noninflammatory protrusion of the central or paracentral region of the cornea. It is worse in allergy sufferers and may result in marked irregular astigmatism. It is also associated with Down syndrome. Gas permeable contact lenses often significantly improve visual acuity as compared with spectacles, although a corneal transplant is indicated in about 15% of patients with this condition. The cause of the condition is unknown, but it likely has a genetic basis.
