Advantages and disadvantages of gas permeable lenses

Also called RGPs, rigid gas permeable or oxygen permeable lenses, gas permeable (GP) contact lenses are less-known than soft lenses. RGPs are different from “hard” contact lenses, which have disappeared today, although they were popular before the invention of soft lenses in 1971. PMMA hard lenses are uncomfortable and prohibit oxygen from passing through the lenses.