A lot of people begin to notice problems with reading small print and seeing close objects during their 40s. This is known as presbyopia. Fortunately, this doesn't mean that people who already wear glasses to tend to their problems with nearsightedness need to carry around two pairs of glasses and continually change them. This is all thanks to multifocal lenses, which correct both problems, making sure you always see clearly.
Before mulifocals, bifocals were the obvious solution, but they were far from all that great; while they help you to focus on both near and distant objects, middle distance is blurred. To create a better product, progressive lenses were invented, which give you a transition part of the lens which lets you focus on the area between near and far distances. How does this work? Progressive lenses are specially curved, unlike a bifocal lens, which is harshly divided. Because of this, progressive lenses are also known as no-line lenses. This makes for not just better vision at near and far distances, but also good transitions between the two.
These lenses, although better, may require some time to adjust to. Even though the gentle transition of progressive lenses 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 children and teens who experience eye strain, which is the result of a struggle to focus while reading.
It's also important to get fitted properly, and avoid store-bought bifocals. Many of these ''ready-made'' glasses are one-size-fits-all, which means that the both lenses contain the same prescription and that the optical center of the lens is not customized for the wearer.
Glasses that aren't properly customized to you can lead to eye strain, discomfort and headaches. Unfortunately, presbyopia is just a part of aging. But keep in mind that multifocal lenses can make all the difference.