Bifocal Eyeglasses Explained
Here at the De Anza Vision Center we’ve had many questions from patients who were considering bifocal lenses. Here are some of the most common:
What are Progressive Lenses?
With most lenses, there can be a line of demarcation between the two vision prescriptions, which can be difficult for some people to get used to. With progressive lenses, the prescriptions gradually fade into each other, much like ombre colors do. Progressives can be more expensive, but the difference can be worth it if you have a hard time adjusting to having a line across part of your eyeglass lens.
How Are Bifocal Glasses Made?
Most bifocals start with the primary lens prescription, the one you need for general distance viewing. Another lens with a different prescription is then applied to the bottom of each original lens, resulting in a surface with two different prescriptions. The prescription glasses generally have a line showing the break where one prescription ends and the other begins. It may seem annoying at first, but it’s relatively simple to get used to the break, and will likely not be a factor in a very short period of time.
How Do I Get Used To Wearing Them?
Begin by looking the the main part of the lens until your eyes adjust and you see things clearly. Hold a book in front of you, about a foot below your normal eyesight. Look downward through the bottom of the lens at the book without moving your head. Read the book for about 30 seconds, then glance up again and look ahead. Practice this a few times a day until the action feels natural and happens without you thinking about it.
How Long Does it Take To Get Used to Them?
It depends entirely on the wearer and how often they practice each day. In general, it takes most people about three weeks before they automatically adjust their viewing without having to think about it. Most people view it as time well spent, though, compared to the annoyance they had before with removing and replacing multiple pairs of glasses.
Are There Problems With Bifocal Eyeglasses?
Other than the initial break-in period, most patients report no problems with general bifocal lenses. Many patients with progressive lenses report problems with their peripheral vision. Because of the way the lens is made, you may have to tilt or move your head initially to see well to the side. Combat this by wearing your glasses constantly, and keeping them as close to the face as possible.