What’s the Difference Between Progressive and Bifocal Lenses?
As we age, our eyes become less flexible making close up objects appear out of focus. This vision problem is called presbyopia. If you don’t already wear prescription glasses a good pair of reading glasses is probably all you need to correct the problem. However, if you already wear glasses, you will need to add a pair of readers to your eyewear wardrobe or switch to a pair of bifocals or multifocal lenses.
Bifocal lenses allow you to see objects clearly both far away and up close; however, they don’t have an area for intermediate objects. Traditional bifocals also have a stigma associated with them. Bifocals, with the noticeable line through the center of the lens, has a tendency to make the wearer look older than they are. Bifocals also have a problem with a noticeable image jump when you switch from looking out the bottom of the lens to see close up objects or out the top of the lens to see items in the distance.
Progressive adaptive lenses (or PALs) are also called no-line bifocals. They have multiple focal distances depending on where you look out of the lens. This allows the user to see clearly at all distances – near, far, intermediate and any distance between. Multifocal lenses with their multiple focal zones tend to have a higher rate of adaptation compared to bifocals with their two distinct focal zones.
The first commercially viable no-line, or seamless bifocals, were invented by Irving Rips in 1955. He went on to start Younger Optics, naming the company after his new lens invention which made people look younger. Bernard Maitenaz patented a modern version of PAL lenses in 1951 introduced to consumers in 1959 under the name Varilux via the company we now know as Essilor.
Progressives have a slight disadvantage compared to bifocals. The peripheral field of vision in PAL’s are slightly distorted compared to lined bifocals. Modern lens designs help reduce this problem and choosing slightly larger frames, with a larger lens, can also help with the peripheral field of vision problem. If you want to forgo glasses altogether, you may want to consider bifocal or multifocal contact lenses. But that’s a topic for another article.
Find Glasses at MyEyeLab
MyEyeLab offers glasses for everyone: single vision, bifocals and multi-focal lenses. Ask your eye doctor about your options for prescription eyeglasses the next time you visit one of our stores. If it’s been awhile since you’ve had your vision checked, schedule an appointment for an eye exam with one of our optometrists.