Have you started to have difficulty when reading fine print? If you're close to middle-age, you might have presbyopia. But developing presbyopia when you already need glasses for distance vision doesn't mean you need to start switching between multiple pairs of glasses. Multifocal lenses will allow you to see clearly always, tending to both issues at once.
Before mulifocals, bifocals were widely prescribed, but they were far from all that great; even though they help you to focus on both near and distant objects, middle distance is blurred. In an effort to create something better, progressive lenses were developed. These offer a transition region allowing you focus on everything between things like the books you read and far objects like road signs. How does this work? Well, progressive lenses are specially curved, unlike a bifocal lens, which is sharply divided. Because of this, progressive lenses are also called no-line lenses. This creates not only clearer vision at near and far distances, but also nice, comfortable transitions between the two.
These lenses can take some time to get used to. Even though the invisible transition of progressive lenses results in a product that is elegant, the lens's areas of focus are small, because they all need to fit.
Even though multifocal lenses (sometimes called trifocals) are for presbyopia, bifocals are often employed to treat children or adolescents who suffer from issues such as eye teaming, or being unable to focus while reading, which causes eye strain.
Multifocal lenses work best when they're customized to your specific needs. So when it's time to get fitted, enlist the services of a professional you feel comfortable with.
If your prescription or fit is off you could end up suffering from headaches, eye strain or even nausea. During middle age, most people will not be able to avoid presbyopia. But it's good to know that good, multifocal lenses can make it a lot easier.