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Jessica Caswell, 4 Nov 2015

How Do Bifocal and Multifocal Contact Lenses Work?

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Corrective lenses have great potential to improve your vision and help you enjoy the world around you. As your vision changes, you may want to explore new options for vision correction. Contact lenses are now available in a variety of prescriptions—some contact lenses include multiple prescriptions—these include bifocal contact lenses and multifocal contact lenses.

If you’ve noticed that you have trouble focusing on nearby objects or reading without holding your book at arms length, bifocal lenses and multifocal lenses may be able to help. Keep reading to learn more about how they work.

Who needs bifocal and multifocal lenses?

As you age, your eyesight changes. Even if you’ve had very good vision in your youth, you will eventually develop presbyopia. This is a condition where the near vision gets weaker and it becomes difficult to read, or focus on close objects. Some younger people also need multifocal lenses, but the need for them increases as you age. In general, people begin to develop presbyopia around age 40. The most obvious sign of presbyopia is the need to hold reading material further away from your face in order to focus. You may also experience headaches or feel like your eyes are strained or fatigued.

What are bifocal lenses?

Bifocal contact lenses generally have two prescriptions (or ‘powers’) in the same lens. The two prescriptions are used to correct near vision and distance vision.

What are multifocal lenses?

Any contact lens with two or more prescriptions (or ‘powers’) is a multifocal lens—this means that all bifocal lenses are also considered multifocal lenses, but not all multifocal lenses are bifocals. Multifocal lenses are also used to correct near and distance vision problems.

How do these lenses work?

When choosing bifocal or multifocal contact lenses, you’ll usually have two options: simultaneous vision lenses or alternating vision lenses.

Alternating vision lenses let you switch back and forth between two powers as your pupil moves up and down. Either you’ll be looking through the section of the lens with the distance viewing power or you’ll be looking through the section of the lens with the near viewing power. Alternating bifocal contact lenses work in a similar way to bifocal eyeglasses—there is a line of separation in the lens and what you are looking at will determine which part of the lens you use.

Simultaneous vision lenses force your eyes to look through distance and near powers simultaneously. Your eyes get used to the lenses and learn to use the correct powers depending on what you are looking at. These lenses require your brain to learn how to adjust what you see. Simultaneous vision lenses are usually either in concentric ring designs or aspheric designs.

Concentric ring simultaneous vision lenses consist of a number of rings with different powers, the rings alternate between near and far vision powers.

Aspheric simultaneous vision lenses blend the different powers together across the lens, so there is a gradual change from near powers to far powers.

What kinds of lenses are available?

Bifocal and multifocal lenses are available in a variety of materials. Vision insurance can make getting the right lenses simple and affordable.

Contact lens options include:

Traditional soft contact lenses that are designed to be used part time. They are comfortable and the eyes adjust to them relatively easily.

Silicone hydrogel soft lenses that let even more oxygen into your eyes than traditional soft lenses.

Rigid gas permeable lenses that allow oxygen to reach your eyes. This can keep your eyes healthier, but it may take your eyes more time to adjust. These lenses are designed to be worn every day.

Disposable lenses that are thrown out at regular intervals. They are then replaced with fresh lenses.

Hybrid lenses that have a rigid gas permeable section in the middle and softer material on the outside to increase comfort and make it easier for the eyes to adapt to the lenses.

What kind of contact lenses should you choose?

Every situation is unique, and the lenses that work for your friend may not be comfortable for you. The type of lenses you need will depend on your vision, your health, your age, your personal preference, and more. Your eye doctor can help you weigh your options and choose the best solution. In some cases you may need to try out a variety of lenses before determining the best fit for you. You may also need to make adjustments as your eyes continue to change.

If you’d like to learn more about protecting your vision and improving your eyesight with contact lenses, visit VSP Direct.