CLAO

Soft Lens Classification

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 Federal Drug Agency (FDA) generally classifies hydrogel lenses into two main categories, i.e., 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 useful for purposes of determining the effects of lens care products upon the lens material.  Disinfection of low water lenses usually can 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

CLAO

NOTE:  The above listings are not meant to be all-inclusive.  Reprinted from the CLAO Quick Reference.

© 2003, 2004, Contact Lens Association of Ophthalmologists, Metairie, LA