What Is the Varifocal Lens?

A varifocal lens is used to correct presbyopia, a vision condition that mostly affects people over age 40. In Europe, Kodak uses the trademarked term "Varifocal" for a lens product, but in the United States the term "varifocal" is often used interchangeably with progressive or no-line bifocal as a name for any multifocal lens.

How Varifocal Lenses Work

• Progressive lenses help you see far away, up close and at many distances in between. The top part of the lenses is your distance prescription; it's the part of the lenses you use for driving, watching movies and and looking across the room. The prescription power of the lenses changes as you look down into the lower part of the lens. This lower part helps you read and see things that are very close. The middle to lower part of the lens is for seeing everything in between far away and close up.

Benefits

• Many people select varifocal lenses for the cosmetic benefit -- the lenses do not show bifocal or trifocal lines. Traditional bifocals and trifocals with lines give you a jolting sensation, called a "jump," as you move your eyes down and look through the lined boundaries between prescription powers. Progressive lenses provide a seamless transition that lets you see more comfortably through the bifocal and trifocal powers and avoid image jump.

Characteristics

• The reading and gradual power changes in varifocal lenses look like a mountain or upside-down U in the lenses; however, because the power change is gradual, the shape is hard to see. If you hold varifocal lenses over a paper with writing on it and move the lenses up and down slowly, you might be able to see the shape of the varifocal powers in the magnification differences in the print.

Considerations

• Give yourself time to adjust to varifocal lenses, especially if you are trying them for the first time. You will need a few days or even weeks to get used to the power progression in the lenses. Some people experience an uneasy sensation, sometimes described as a "swimming" motion, as they look through varifocal lenses. The more you wear your progressive lenses, the more quickly you will get used to them.

Tips

• Most manufacturers of progressive lenses give you up to 60 days to try your new lenses, and if you can't adjust to the prescription, they will exchange your lenses for regular lined bifocals or reading lenses.