A type of plastic used in rigid contact lenses prescribed from the 1930s to the late 1970s.

Polymethylmethacrylate, a polymer plastic commercially available for example as Perspex or Lucite.

This material is the clear medical polymer used to make Intacs. This material has been used since 1952 in the intraocular lenses used in cataract surgery and for contact lenses. PMMA has been proven to be biocompatible (i.e., it does not cause a reaction when placed in the eye).