Multifocal contact lenses are designed to help people with presbyopia, a condition that affects the ability of the eye to focus on objects up close. Unlike single-vision contacts, which only have one prescription strength, multifocal lenses have multiple prescriptions that are layered on top of each other. This allows the wearer to see objects at different distances.
How do multifocal contact lenses work?
The way that multifocal contact lenses work is by using a technology called "simultaneous vision," which allows the eye to focus on multiple distances at the same time. This is accomplished by creating two or more prescription powers in the lens, with each power focused on a different distance.
What are the types of multifocal contact lenses?
There are two main types of multifocal contact lenses: alternating vision lenses and simultaneous vision lenses. Alternating vision lenses, also known as "alternating bifocal" or "alternating trifocal" lenses, are designed to help the wearer see clearly at different distances. Alternating vision multifocal lenses are designed to allow the wearer to switch between two different powers as their pupil moves up and down. A dividing line in the lens usually helps the wearer know which part of the lens to use for different tasks. For example, when looking straight ahead at a distance, the wearer would use the distance prescription power, but when looking down to read or do other close-up work, they would switch to the near prescription power. This allows the wearer to see clearly at multiple distances.
Simultaneous vision lenses allow wearers to see clearly at multiple distances simultaneously. These lenses are designed with two or more prescriptions layered on top of each other, with each power focused on a different distance. As the wearer looks at different objects, their brain must learn to adjust to the varying powers of the lens, which may take some time to get used to. However, with regular use, the brain will become more adept at using the lenses and the wearer will be able to see clearly at multiple distances. Simultaneous vision lenses are available in aspheric or concentric ring designs.
Aspheric multifocal simultaneous vision lenses are designed to blend the different strengths together across the lens, resulting in a smooth, progressive change from the distance prescription power to the near prescription power. This allows the wearer to see clearly at multiple distances without the need for a dividing line in the lens.
Concentric ring multifocal simultaneous vision lenses are made up of multiple rings with different strengths, arranged in an alternating pattern. The rings with the distance prescription power are positioned around the center of the lens, while the rings with the near prescription power are positioned around the outer edge of the lens.
What brands produce multifocal contact lenses?
There are several different brands of multifocal contact lenses available on the market, including Acuvue, Bausch + Lomb, and CooperVision. It's important to consult with your optometrist to determine which brand and type of multifocal lens are best for your individual needs.