Bifocal lenses are eyeglasses designed to help people see clearly at two different distances: near and far. They have two distinct optical zones, with the upper part for distance vision and the lower part for reading or close-up tasks. This design allows individuals with presbyopia, a common age-related vision change, to switch between distances without needing to change glasses. These lenses are typically made from glass or plastic and can be customized to fit individual prescriptions. Bifocal lenses can also come in various styles, including flat-top and round segment, catering to different preferences and needs.