How Varifocal Lenses Work

Varifocal progressive lenses use a simplistic design because they function through a single lens. They work by providing gentle, gradual changes of visual distance throughout the lens material: Distance vision at the top, intermediate vision in the center, and near vision at the bottom of the lens. You can see at varying distances depending on where you look through the lens.

With all of the good that comes from varifocal lenses, the design does have some drawbacks. It can take a long time for your brain to adapt to how the lenses work. Because there aren’t any visible lines in the lenses to help guide your eyes to the magnification you need, you must train yourself to know where to look. For example, 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 eye- and brain-training process, you may experience symptoms including eye strain, headaches, dizziness, and nausea.

Tips for Adapting to a Varifocal Lens

These are some ways to help you adapt to using varifocal lenses:

• Don't move your eyes to see at different distances. Instead, move your head and point your nose where you need to look.

• Give yourself enough time to adapt. It might take days or even a few weeks for you to adjust to varifocal lenses.

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

Varifocal vs. Bifocal and Trifocal Lenses

In contrast to varifocals, which have magnification changes gradually throughout the lenses, bifocals and trifocals have two and three visual magnification areas respectively. Those different magnification areas are divided by visible "transition lines." These different areas can cause something called an "image jump.” This is when something you’re looking at changes in clarity and apparent position as you look across the prescription lines in the lenses.

• Bifocals: These lenses offer help for both close-up and far vision, with one line dividing the lens. This dividing line is sometimes visible and sometimes invisible. To see things more clearly close up, you look into the bottom of the lens. To see into the distance, you look through the top area of the lens.

• Trifocals: As you might expect from the "tri" part of the word, trifocals have three visual magnification areas: close-up, mid-range, and far vision. You look through the bottom for close-up, the middle for mid-range, and the top edge of the lens for long distance.

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.