Myopia and hyperopia are the most common vision problems. In most cases, people with vision problem suffer from either myopia or hyperopia. At the same time, most prescription glasses are designed to correct only one type of refractive error.
However, there are some people who have both of the two vision problems. They need vision correction of both distance and near objects. Of course, these single vision eyeglasses are incompetent. Only bifocal eyeglasses can provide the needs for such a group of people. A bifocal lens has two lenses, one for myopia correction and the other for hyperopia correction. To wit, there are actually four lenses in a pair of bifocal eyeglasses.
Most people will need bifocal glasses only when they become older. At early ages, single vision eyeglasses are enough. Bifocal lenses can always reduce eye strain in early stages. Customers should make a consultation with an optometrist before choosing bifocal eyeglasses, because there are various styles of bifocals now.
Bifocal lenses in an old design have a visible line in each lens, which brings an unnatural look. Modern progressive lenses effectively remove the line. They provide clear vision irrespective what and where the object is. There is no line that will affect visual perception. While ensuring normal visual correction of both nearsightedness and farsightedness, progressive lenses appear more naturally.
The modern design of a bifocal lens is that the lower portion for closer objects and the upper part for distance vision. The reason for this design is that people always put their heads slightly down when they try to read and write. However, customers will always get unsatisfied if they expect bifocal eyeglasses to deal with all situations. When it comes to computer use, the common bifocal design is not suitable, because the computer monitor is directly in front of the lenses.
In some cases, bifocal contact lenses are better than bifocal eyeglasses. People wearing bifocal contacts never need to move their heads in order to see through the proper part of the lenses. Moreover, contact lenses offer wider peripheral vision.
