Hydrogel (soft) contact lenses have a generic name that usually end in the suffix "filcon", meaning "water loving", while nonhydrogel lenses usually end in "focon", meaning "water fearing." The FDA generally classifies hydrogel lenses into two main categories: low water and high water lenses. The FDA further divides these two groupings into ionic and nonionic. In general, nonionic lens surfaces are considered "nonionic" and more reactive surfaces are considered "ionic." These four groupings are useful for determining the effects of lens care products upon the lens material. Disinfection of low water lenses can usually be done with any care system. High water lenses typically should not be thermally disinfected. Check the package insert of all dispensed contact lenses for the manufacturers recommended care system.

Group 1 ( <50% H2O, nonionic polymers)

telfilcon, tetrafilcon A, crofilcon, helfilcon, mafilcon, polymacon, lotrafilcon A.

Group 2 ( >50% H2O, nonionic polymers)

lidofilcon B, surfilcon A, lidofilcon A, netrafilcon A, hefilcon C, alfafilcon A, omafilcon A, vasurfilcon A, hioxifilcon A, nelfilcon A, hilafilcon A

Group 3 ( <50% H2O, ionic polymers)

bufilcon A, deltafilcon A, droxfilcon A, phemfilcon A, ocufilcon, balafilcon A

Group 4 ( >50% H2O, ionic polymers)

perfilcon, etafilcon A, focofilcon A, ocufilcon B, ocufilcon C, ocufilcon D, ocufilcon E, phemfilcon A, methafilcon A methafilcon B, vilfilcon A