Bifocals are a type of eyeglasses designed to help people see clearly at two different distances: near and far. They typically have two distinct optical zones, with the upper part of the lens for distance vision and the lower part for reading or other close-up tasks. This design allows individuals, especially those with presbyopia, to switch between seeing far away and up close without needing to change glasses. Invented by Benjamin Franklin in the 18th century, bifocals have become a popular solution for those experiencing age-related vision changes. They are available in various styles and materials, making them suitable for different lifestyles and preferences.