Bifocal lenses are designed to help people with difficulty seeing near and far distances, a condition often associated with presbyopia (age-related difficulty focusing on close objects). Here’s how they work:
1. Two Lens Powers in One: Bifocal lenses have two distinct optical powers. The upper part of the lens is typically for distance vision, while the lower part is for near vision, such as reading or looking at a phone.
2. Segmented Design: The near-vision portion is usually a small, semi-circular or rectangular segment at the bottom of the lens. This allows the wearer to look through the top part for far-away objects and through the bottom part for close-up tasks.
3. Natural Eye Movement: When you look straight ahead, your eyes naturally align with the upper part of the lens for distance vision. When you look down, your eyes align with the lower segment for near vision.
4. No Gradual Transition: Unlike progressive lenses, bifocals have a visible line separating the two lens powers, and there’s no gradual transition between them.
Bifocal lenses are a practical solution for people who need correction for both near and far vision in a single pair of glasses.
