If you are around 40 and having some difficulty reading small print, you may have developed presbyopia, a common age-related condition that prevents you from clearly seeing near objects. But having presbyopia when you already wear glasses for distance vision doesn't mean you now need multiple pairs of glasses. Multifocal lenses, which correct both myopia and presbyopia, let you see clearly at all distances with one pair of glasses.
Before mulifocals, bifocals were widely prescribed, but they have a significant shortcoming; while they correct problems with both near and distant objects, everything else is blurred. In an effort to correct this problem, progressive lenses were made. These offer and intermediate or transition region that allows your eyes to focus on distances that are in the middle. But what creates this effect? Progressive lenses feature a gradual curvature, unlike a bifocal lens, which is sharply sectioned. Because of this, progressive lenses are also called no-line lenses. This makes for not only better vision at near and far distances, but also nice, easy transitions between the two.
However, you might require some time to adjust to no-line lenses. Despite the fact that the gentle lens curve results in a product that is aesthetically pleasing, the focal areas are relatively small because more lens space is used for the transitional areas.
Even though these progressive lenses (or trifocals) are for presbyopia, bifocals are still used to help children or adolescents who have other eye problems like eye teaming, or being unable to focus while reading, which in turn, can lead to eye strain.
It's also important to get fitted properly, and not turn to drugstore bifocals. A lot of these ''ready-made'' glasses are one-size-fits-all, which means that the both lenses contain the same prescription and that the optical center of the lens is not customized for the wearer.
Wearing a wrong prescription can leave you with headaches, eye strain or even nausea. During middle age, most people cannot dodge presbyopia. But it's good to know that good, multifocal lenses can make all the difference.