Bifocal contact lenses are lenses designed to address the focusing issues associated with presbyopia by incorporating different prescriptions.
“Presbyopia” is the vision problem that everyone encounters between the ages of 40 and 45. During this time, your eyes lose the ability to focus clearly on small text that’s close to you, like a newspaper, menu, or book.
Bifocals can help you read. But, as we’ll learn, this doesn’t have to be bifocal eyeglasses. To learn more, let’s introduce you to bifocals and walk through what to consider if you’re thinking about getting bifocal contacts.
What are bifocal contact lenses?
Bifocal contact lenses are lenses that offer two different prescriptions in a single lens. One prescription is for close reading, and the other for normal, distance vision. The dual prescriptions help people who suffer from presbyopia, where age-related changes to the eye cause difficulties in focusing on close objects.
What’s the difference between bifocals and multifocals?
Bifocal contact lenses are designed with a defined line between the near vision prescription and the distance prescription. You switch back and forth between zones, as you would with bifocal eyeglasses. Multifocals have a gradual transition between near and far.
Types of bifocal contacts
There are two types of bifocal contact lens designs. The first mimics bifocal eyeglasses closely, with a separate section for each prescription. This is called a segmented bifocal, and sometimes also referred to as an alternating or translating bifocal. Usually, the near vision prescription is in the lower part of the lens, and the normal, distance prescription is in the rest of the lens.
The second type of bifocal contact lens has a concentric design. The centre of the lens has the normal vision prescription, and the surrounding ring has the near vision prescription. This is called a concentric or simultaneous bifocal.
Bifocal lenses come in both soft and rigid gas permeable (RGP) or hard lens materials.
Choosing bifocal contact lenses
Here are some good considerations for deciding whether bifocal contact lenses are for you.
Benefits of bifocals
- The upside to bifocals is that you:
- No longer need reading glasses.
- Have high visual acuity for both near and distance vision.
- Are similar to bifocal eyeglasses, sometimes requiring less adjustment.
Drawbacks to bifocals
- Bifocal contacts can sometimes be difficult because:
- You have to learn how to switch between prescriptions.
- They can sometimes affect depth perception.
- They can cause eye strain, especially when segmented bifocals (with reading prescription in the lower lens) are combined with heavy computer work.
Bifocal contact lens alternatives
There are many good alternatives if bifocals don’t sound appealing to you, or if you try them and you and your optometrist decide they may not be the most appropriate option.
Non-surgical alternatives include:
- Normal, distance contacts combined with reading glasses
- Monovision contact lenses
- Multifocal contact lenses
Remember, getting or switching contact lenses is a decision you should make with your optometrist. The correct prescription and fitting is critical to the health, comfort and performance of your eyes.