Many people start to have problems with close vision during their 40s. This condition is known as presbyopia. It's one of the harsher realities of getting older, but it's good to know that developing presbyopia when you already need glasses for near sightedness doesn't mean you now need two pairs of glasses. This is all thanks to multifocal lenses, which correct both problems, making sure you always see clearly.
Multifocals are far superior to bifocals. Bifocals corrected problems with both near and far vision, but often things in between were blurry. To correct this problem, progressive lenses were made. These offer a transition part of the lens which lets you focus on the area between things like the books you read and street signs. How does this work? Progressive lenses are specially curved, unlike a bifocal lens, which is harshly sectioned. Because of this, progressive lenses are also called no-line lenses. This makes for not just better vision at near and far distances, but also nice, easy transitions in between.
Progressive lenses may take some time to get used to. While the subtle lens curve is more elegant, 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 kids and teenagers who suffer from eye strain, stemming from a struggle to focus while reading.
It's also crucial to get fitted properly, and not resort to store-bought bifocals. A lot of these types of glasses have the same prescription in both lenses, which will not help a lot of people.
If your prescription or fit is off you could end up suffering from headaches, eye strain or even nausea. Presbyopia catches up to most of us at a certain age, but it doesn't have to be restricting. A simple pair of multifocals will make a world of difference.