Conical protrusion of the cornea.
A coneshaped lump on the cornea.
A protrusion and thinning of the apical portion of the cornea, of obscure etiology, in which vision is best corrected by a contact lens.
Cone-shaped protrusion of the cornea; it may be treated by special contact lenses or by epikeratophakia.
Disease that involves a progressive, gradual thinning of the clear outer covering of the eye (cornea) and changes its shape from a dome to a cone; also known as conical cornea. The change in the cornea’s shape causes nearsightedness (blurring of distant objects) and astigmatism (tilting and distortion of the field of view), which can range from mild to severe. Most cases of keratoconus begin in adolescence or early adulthood and progress over a lo- to 20-year period. Keratoconus has a number of possible causes, including an inherited abnormality of the cornea, certain eye diseases (for example, retinitis pigmentosa and vernal keratoconjunctivitis), and some systemic diseases, such as Down syndrome. Treatment depends on the severity of the disease. Eyeglasses can correct nearsightedness and astigmatism in the early stages. In more severe cases, rigid contact lenses are used to flatten the surface of the cornea and provide improved vision. If vision remains badly impaired even with contact lenses, the person may need to undergo a corneal transplant.
An abnormal condition of the eye in which the cornea, instead of having a regular curvature, comes to a rounded apex toward its center. The cone tends to become sharper with age. It is usually due to a congenital weakness of the center of the cornea, but may not produce symptoms until later childhood.
A hereditary, degenerative corneal disease resulting in a conical protrusion of the central cornea with thinning. It is often bilateral, occurring in the second decade of life. Initially, the disease is asymptomatic with a decrease in vision, correctable with glasses. Significant astigmatism is associated with progression of the disease. Rigid contact lenses and eventually a corneal transplant may be needed to improve vision. Perforation of the thinned central cornea may result and is called hydrops, which can significantly decease visual acuity.
A visual disorder characterized by the protrusion of the cornea, leading to impaired vision. Typically, this condition affects both eyes simultaneously.
A hereditary eye condition leads to a gradual thinning and conical distortion of the cornea (the transparent front portion of the eyeball). This disorder impacts both eyes and typically emerges around puberty, resulting in growing myopia (near-sightedness) and a progressive alteration of vision that cannot be fully rectified with eyeglasses. In the initial stages, rigid contact lenses can enhance vision, but as the condition progresses, a corneal transplant is generally required to permanently reinstate normal vision.