The idea of someone wearing bifocals may conjure the image of a hunched-over elderly person, but that is an antiquated, stereotypical view of the type of person who needs bifocals.

Older adults may be more inclined to ask the optometrist, "Should I get bifocals?" 

But age is just a number when it comes to bifocals. Even young children sometimes are prescribed bifocal lenses to protect their eyesight and improve their ability to see when switching between different distances. Bifocals should not have a stigma. 

In fact, nearly 30 percent of the population is affected by nearsightedness, according to the American Optometric Association. Of course, bifocals have evolved quite a bit since Benjamin Franklin first invented them back in 1780 and have even evolved from the ones your great-grandma used to wear. Getting used to bifocals is easier than ever because the extra lens is blended into the glass without a clear dividing line. They even exist in the form of contact lenses so no one has to know you are wearing them. 

Do I need bifocals? 

Regardless of your age, if your eyes have trouble with alternating from farsightedness and nearsightedness, you may need bifocal lenses. The problem is a curvature of the eye's lens that changes how light is filtered and makes it difficult to focus when switching back and forth from short to long distance. 

Heredity and eye or visual stress may be the most common causes of nearsightedness. Environmental factors and work conditions also may contribute over time. Frequent computer use can worsen the condition. Farsightedness may be related to heredity. 

An eye doctor can perform an optometric exam to determine if you have nearsightedness and farsightedness and if you could benefit from wearing bifocal lenses. 

How Bifocal Lenses Work 

The purpose of bifocals is to make the transition easier when switching from looking at items close up and far away. They help bring far-away items into focus. If not for the double lens, patients would require two separate prescriptions for different purposes and may have to change glasses more frequently, depending on whether they are looking at close or distant items. 

Dr. Ravi D. Goel, an ophthalmologist and instructor at the Wills Eye Institute tells CNN Health, "Think of the lens system of the eyes as you would a trampoline. When you're young, the lens (the center of the trampoline) is held in place by lens zonules (the strings of the trampoline). The lens zonules are strong, and they are able to move back and forth to bring images into focus. As you grow older, these 'strings' start to relax, which makes it more difficult for you to control the movement of the lens to bring an image into focus. As these lens zonules relax, you can either hold an object farther away or use bifocals to bring an image to a more comfortable position. Bifocals are the cure for arms that are not long enough." 

People often find that it can take up to a few weeks to adjust to using them. They may cause headaches, dizziness and blurriness initially, but they can correct nearsightedness and bring far away items into focus. 

Can bifocals slow the progression of nearsightedness? 

Too much of a lens curve in the eye can cause nearsightedness, or myopia, in which light isn't properly directed to be able to see at a distance. While surgery could correct the lens, a much less invasive method for correcting it is to wear bifocal glasses or contact lenses. 

A study that included 85 children between ages six and 11 over a two-year period found a slight slowing of myopia progression in the kids who wore bifocals, compared to those who wore single-vision lenses. David Berntsen of the University of Houston College of Optometry and others from Ohio State University published the study in the journal Investigative Ophthalmology and Visual Science. 

"Single-vision lenses are normally prescribed when a child gets a pair of glasses, but glasses with progressive addition lenses were shown to slightly reduce myopic progression in our study," Berntsen said. "For any treatment that reduces myopia progression in children to be useful, the effect of the spectacles or contact lenses must persist after children stop wearing them. The fact that the small treatment effect from our study was still present one year after discontinuing the treatment is promising. The results suggest that if newer optical designs currently being investigated do a better job of slowing myopia progression, the effects may be expected to persist and decrease how nearsighted the child ultimately becomes." 

The study offers a jumping-off point for additional research, while providing hope that bifocals can slow the progression of nearsightedness in children. This can reduce the need for surgery and prolong vision for as long as possible. 

The Future of Bifocals 

Bifocals have evolved since their creation, but research continues to examine whether they can be used early in life to prevent further damage and vision loss. They aren't just made for older people, nor do they have to look like they're designed for the elderly. New materials are being used and new technologies are advancing the use and look of bifocal lenses. 

Guoqiang Li, a researcher at the University of Arizona, and his team created new electronic bifocals, for example. In the prototype, "each lens consists of two flat glass plates with a hair-thin layer of shape-shifting liquid crystal sandwiched between," Li told LiveScience. One plate features small electrodes through which a current runs, causing "the liquid crystals to rearrange and mimic the nearby focusing power of a human eye lens."

The best way to tell if you need to get bifocals is to observe your own behavior. Do you squint when reading or hold material at arm's length to focus better? If you find yourself adjusting to make seeing easier, it may be time to schedule an appointment with an ophthalmologist or optometrist.