Round-the-clock-lenses is just like it sounds, lenses you may have around the clock for up to 30 days and are popular among young people. Unlike disposable lenses and monthly lenses, you do not spend time putting in and removing them from the eyes every day, you do not clean them or store them in liquid overnight.
Round-the-clock-lenses are made of a special material called silicone hydrogel. Silicone hydrogel as a contact lens material has meant a breakthrough over traditional hydrogel lenses, as it passes up to six times as much oxygen. A high oxygen supply to the eye is important for a comfortable and healthy lens wear and this makes it possible to sleep with these lenses. Eyes can basically "breathe" normally.