How Varifocal Lenses Work

Varifocal progressive lenses utilize a simplistic design since they're a single lens. They work by providing gradual changes in the visual distance throughout the lens material. You look through the top for distance vision, you look through the center for intermediate vision, and you look through the bottom of the lens for near vision. You can see at varying distances depending on where you look in the lens. The invisible section breaks in the lens have some drawbacks, one being that it can take time for your brain to adapt to how they function. Because there aren’t any visible lines in the lenses, you have no guide to know exactly where to look. You must train yourself to know where to look. For instance, you'll need to look down at the right spot for reading, straight ahead for distance, and between those two areas for intermediate distance or computer work. During this “training” process, you may experience symptoms including eye strain, headaches, dizziness, and nausea.

Tips for Learning How to Use Varifocal Lenses

Ways to help you adapt to using varifocal lenses:

• Move your head and point your nose where you need to look instead of moving your eyes so much.

• Give yourself time to adapt to the varifocal lens. It might take days or weeks for you to get used to the way varifocal lenses work.

• Don't give up — keep wearing them (though you can take them off briefly to give yourself a break). If you're struggling, contact your eye doctor for further advice.

Varifocal vs. Bifocal and Trifocal Lenses

While varifocal lenses offer gradual magnification changes throughout the different parts of the lens, bifocals and trifocals have two and three physical magnification areas respectively. They are divided by visible "transition lines." These changes in bifocals and trifocals can cause something called an "image jump." This is where what you're looking at can quickly alter in clarity and position as you look across the prescription lines in the lenses.

• Bifocals help with both close-up and far vision, with one line dividing the lens (sometimes this line is visible, sometimes it is not). To see close up, you look through the bottom of the lens. To see long distances, you look out through the top area of the lens.

• Trifocals have three visual magnification areas: close-up, mid-range, and far vision. You look into the bottom, middle, and top parts of the lenses for the different visual areas.

Another difference between the lens types can be the cost. Varifocal lenses can be more expensive than bifocal and trifocal lenses due to their unique single-lens design.