Continuous wear contact lenses are available for overnight or continuous wear ranging from 1 to 6 nights or up to 30 days. Continuous wear contact lenses are usually soft contact lenses. They are made of flexible plastics that allow oxygen to pass through to the cornea. There are also a very few rigid gas permeable lenses that are designed and approved for overnight wear. Length of continuous wear depends on lens type and your eye care professional's evaluation of your tolerance for overnight wear. It is important for the eyes to have a rest without lenses for at least one night following each scheduled removal.