[Contact lenses--an overview].

Contact lenses are a modern possibility to correct defective sights as an alternative to glasses. They are not only used because of cosmetic reasons but also if there is optical or therapeutical indication from the medical point of view. For keratoconus and cornea globosa are hard contact lenses not only the unique efficient possibility for correction but also contemporary therapy. If cornea is irregular-for instance when there are cicatrices-an essential improvement can be achieved with hard contact lenses in comparison to glasses.