Purevision multi focal is a silicone hydrogel based contact lens designed for replacement every month these contact lenses provide all in one vision correction for people who cannot see clearly into the distance or focus effectively on closeby objects purevision multi focal lenses can be worn whilst the wearer is awake or continuously whilst the wearer is awake and asleep however not all eyes are suited to continous wear of purevision multi focal lenses and only an optician can determine the