Daily Wear: Lenses prescribed for daily wear are to be worn only during waking hours, usually up to a maximum of 18 hours. 

Daily wear lenses are removed at night and cleaned and disinfected after each removal.

Extended Wear: Extended wear lenses may be worn on an overnight basis for up to seven consecutive days (six nights). You should wear your lenses on an extended wear basis only on the advice of your optometrist.

Extended wear lenses generally have a higher water content or thinner center thickness than other lenses and permit more oxygen to reach the eye. However, their use has been linked to a higher incidence of eye problems. 

Extended wear lenses need to be cleaned and disinfected at recommended intervals or discarded after use.