Bausch & Lomb PureVision Multi-Focal lenses feature an innovative optical design allowing you to see clearly at all distances ? near, far, and everywhere in-between. Because PureVision Multi-Focal lenses are 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. Designed to provide 30 days of excellent vision and comfort ? easy to remember to replace them once a month.