Presbyopia, or far-sightedness, is a common condition that usually starts to develop in people who are 40 or older. It's comforting to know that developing presbyopia when you already need glasses for near sightedness doesn't mean you need to start switching between two pairs of glasses. Multifocal lenses, which correct both myopia and presbyopia, let you see clearly at all times, with one pair of glasses.
At one point, bifocals were the obvious solution, but they weren't all that great; even though they help you to focus on both near and distant objects, everything in between is blurred. To create a better product, progressive lenses were developed. These offer and intermediate or transition region that allows your eyes to focus on everything between things like the books you read and street signs. 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 provides not only clearer vision at near and far distances, but also good transitions between the two.
These lenses, although better, can take a small period of time to adjust to. Even though the invisible transition of progressive lenses is more aesthetically pleasing, the focal areas are quite small because more lens space is used for the transitional areas.
Bifocals still have their uses though; they are helpful for children and teenagers who have a hard time focusing when reading.
It's also important that you get professionally fitted, and not turn to store-bought bifocals. A lot of these ''ready-made'' glasses are one-size-fits-all, which means that the both lenses contain the same prescription and are not customized for the wearer.
If your prescription or fit is off you could end up suffering from headaches, eye strain or even nausea. At a certain age, most people cannot dodge presbyopia. But it's important to know that good, multifocal lenses can enrich your vision, and your life.