If you are around 40 and beginning to observe some difficulty reading fine print, you may have presbyopia, a common age-related condition that makes it challenging to focus on close objects. If you already struggle with distance vision, and develop presbyopia, you won't have to start carrying and switching between two pairs of glasses. This is because of multifocal lenses, which correct both problems, making sure you always see well.
At one point, bifocals were widely prescribed, but they have a significant shortcoming; while they help you to focus on both near and distant objects, everything else is blurred. To correct this issue, progressive lenses were invented, which offer a transition part of the lens which lets your eyes to focus on the area between things like the newspaper and street signs. Progressive or no-line lenses are a type of multifocal lens featuring a subtle curvature across the lens, instead of an obvious and harsh line separating the two areas of the lens. This creates not just clearer vision at all distances, but also good transitions in between.
However, you might take some time to get used to these lenses. While the subtle transition of progressive lenses 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 (also called trifocals) are for presbyopia, bifocals are still used to help children or adolescents who have other issues such as eye teaming, or being unable to focus properly, which causes headaches.
It's also important to get professionally fitted, and not resort to store-bought bifocals. Most of these types of glasses are one-size-fits-all, which means that the prescription is the same in both lenses and are not customized for the wearer.
If your prescription or fit is off you could find yourself suffering from headaches, eye strain or even nausea. Presbyopia catches up to the majority of us when we reach a certain age, but there are ways to make it less restricting. A simple pair of multifocals can make a world of difference.