Keratoconus
Keratoconus is a congenital corneal disease (autosomal dominant or autosomal recessive) and is included in the group of corneal dystrophies (hereditary diseases of the cornea which lead to deformation). The typical characteristic of the disease is the change in the structure of the corneal tissue. The keratoconic cornea is thinner and steeper than a regular cornea. Keratoconus usually occurs in both eyes and is usually asymmetrical. The first symptoms occur in the adolescence. The first symptom patients recognize is a gradual increase vision disorder (progressive myopia or astigmatism).
On microscopic examination of the eye, disease-specific changes are observed, such as iron residues, in the cornea. In advanced cases, a thinning is observed in one third of the lower cornea, and Vogt lines are found. Cloudings are observed in the cornea tissue because of increased water content.
Examinations performed with assistance of devices, including cornea topography (determination of the corneal surface), are beneficial in the diagnosis of early disease and the potential progression of the disease can be predicted.
A complete healing is not possible, because the disease is present in the genes. In advanced cases, hard contact lenses may improve vision, but they can not prevent the disease from progressing. Until just a few years ago, the only treatment option to improve vision in advanced cases was corneal transplantation (penetrating keratoplasty). Nowadays, new methods are used to manage keratoconus.