PureVision is a monthly disposable lens that can be worn 24 hours a day for up to 30 days. Because Purevision is made of aerGel, a unique material that lets natural levels of oxygen reach your eyes, they stay comfortable and healthy while resisting protein and debris buildup on the lens. You may hardly notice you're wearing lenses at all. PureVision's revolutionary new material allows up to five times more oxygen to the cornea than conventional soft lenses to promote ocular health.