Bausch & Lomb PureVision contact lenses are made to be worn as Monthly Disposable lenses for up to a month and replaced with fresh, clean lenses to keep your eyes free from calcium deposits that can build up on the lenses and aggravate your vision. Some PureVision users are able to wear there lenses for the entire month, even during the night as they sleep. PureVisionsís optical design corrects spherical abnormality and offers you the best vision possible. Finding contact lenses in cleaning solution can be difficult, so Purevision Contact Lenses come visibly tinted to help you locate them. PureVision contact lenses are made of balafilcon A with a water content of 36%.