HEMA is an abbreviation denoting hydroxyethyl methacrylate - hydrophilic (water binding) material used for the production of contact lenses. The discovery of this material meant a real revolution in the development of contact lenses. It was the first time this elastic material was used for contact lens manufacturing. That lead to the mass production of soft contact lenses which soon all but replaced hard lenses. The material polyHEMA was discovered by Czech scientists Otto Wichterle and Drahoslav Lima and was patented in 1953. Gradually the production process has been simplified by improved lens production systems using a centrifugal casting, thereby minimizing production costs. The use of contact lenses soon spread widely.