Biotrue ONEday maintains nearly 100% of its moisture for a full 16 hours, that takes moisture to a whole new level. Biotrue ONEday contact lenses are inspired by the biology of your eyes. While other lenses dry out as the day passes, Biotrue ONEday contacts retain moisture naturally produced by the eye. The result is consistently clear vision and comfort until the moment you take them out. 30 lenses per box.