Many people develop problems with close vision during their 40s. This condition is called presbyopia. If you're already a glasses wearer, and develop presbyopia, you don't have to start carrying and switching between two pairs of glasses. Multifocal lenses let you have good vision always, tending to both issues at once.
Before mulifocals, bifocals were the obvious solution, but they have a significant flaw; while they correct problems with both near and distant objects, everything in between is blurred. In an effort to create something more helpful, progressive lenses were made. These offer and intermediate or transition part of the lens that allows you focus on distances that are in the middle. Progressive lenses, which are also known as no-line lenses, are a type of multifocal lens that have a gently curved lens surface rather than a noticeable line distinguishing both areas of the lens. This provides not just better vision at all distances, but also nice, easy transitions in between.
These lenses, although better, may require some time to get used to. Despite the fact that the subtle transition of progressive lenses is more aesthetically pleasing, the focal areas are quite small because the transitional areas also inhabit room.
Bifocals aren't entirely dated though; they are helpful for children and teenagers who have a hard time focusing when reading.
Although it may appear to be an easy solution, avoid purchasing drug store bifocals. A lot of these ''ready-made'' glasses have the same prescription in both lenses, which will not help a lot of people.
Being fitted with an incorrect prescription can lead to headaches, eye strain or even nausea. Unfortunately, presbyopia is a reality of our bodies' aging process. But keep in mind that multifocal lenses can make all the difference.