Presbyopia, or far-sightedness, is a common condition that often begins to affect people who are 40 or older. Fortunately, this doesn't mean that those who already have prescription eyeglasses for distance vision are required to own two pairs of glasses. Multifocal lenses will allow you to see clearly always, tending to both issues with just one pair of glasses.
In the past, bifocals were the obvious solution, but they weren't all that great; while they correct problems with both near and distant objects, everything in between is blurred. In an effort to rectify this issue, progressive lenses were invented. These provide wearers with and intermediate or transition part of the lens allowing your eyes to focus on the area between things like the books you read and far objects like road signs. Progressive lenses, which are also known as no-line lenses, are a type of multifocal lens that have a gently curved lens, rather than an obvious and harsh line distinguishing both areas of the lens. This makes for not just clearer vision at all distances, but also nice, easy transitions in between.
These lenses, although better, can take some time to get used to. Despite the fact that the subtle lens curve results in a product that is elegant, the lens's areas of focus are small, so that there's also room for transitional areas.
While these days, these progressive lenses (sometimes called trifocals) are for presbyopia, bifocals are still used to treat children or adolescents with eye problems such as eye teaming, or being unable to focus properly, which in turn, can lead to eye strain.
It's also important that you get professionally fitted, and not resort to drugstore bifocals. Many of these types of glasses are one-size-fits-all, which means that the prescription is the same in both lenses and that the optical center of the lens is not customized for the wearer.
If your prescription or fit is off you may find yourself suffering from eye strain, discomfort and headaches. During middle age, most people will not be able to avoid presbyopia. But it's good to know that the right lenses can enrich your vision, and your life.