title: Rigid lenses: an overview.
abstract: New gas permeable rigid contact lens materials, by allowing direct transmission of oxygen, provide significant advantages over PMMA. Edema resulting from oxygen deprivation with PMMA lenses is eliminated and comfort is increased. Three types of gas permeable materials are described: CAB, silicone, and a combination of CAB and silicone.
mesh_terms: D000085:Acetates; D002087:Butyrates; D002482:Cellulose; D003261:Contact Lenses / Q000592:standards*; D003315:Cornea / Q000502:physiology; D003316:Corneal Diseases / Q000517:prevention & control*; D004487:Edema / Q000517:prevention & control; D006801:Humans; D008768:Methylmethacrylates; D010101:Oxygen Consumption; D010539:Permeability; D012828:Silicones
chemical_list: D000085:Acetates; D002087:Butyrates; D008768:Methylmethacrylates; D012828:Silicones; D002482:Cellulose