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Bifocals are a type of prescription eyeglasses designed for people who need both near and farsighted vision correction. Different from single vision lenses, they have two corrective lenses on each side of a pair of glasses, for a total of four lenses per pair.
Many people wear single vision corrective lenses for a number of years until their vision changes and they require bifocals for total vision correction. However, there remains a misconception that only aging people require this type of glasses. While its true that a person’s vision may change with age, requiring a switch from single vision lenses to bifocals, many people suffer from a combination of near and farsightedness long before they realize it. In some cases, bifocals can also help correct astigmatism that is present in combination with other refractive defects.
There are a few different types of bifocals, and a licensed optician can help patients with a prescription choose the best kind for their needs. Developments in the engineering of the lenses have been made over the years to eliminate the lines in many corrective bifocals. Progressive lenses, for example, correct vision at different powers depending on where one looks through the lens, but the lines are absent.
Though most people who require bifocals have difficulty focusing on objects both up close and far away, they have always been designed with the corrective lens for close range focusing at the bottom and the corrective lens for distance vision at the top. While this design once made sense, because close range focusing was generally required for reading and writing, activities traditionally preformed while looking down, more and more people find it awkward to use such lenses with a computer. Since the computer monitor is directly in front of the user, the up close corrective lens seems out of place on some glasses.
There are new lenses in development to correct this common problem, but in the mean time, many people who require bifocals have found that contact lenses are the best option for their vision correction. There are many advantages to wearing contact lenses rather than glasses, including improved visual acuity. Contacts provide better peripheral vision and eliminate the need to adjust the angle of the head for computer use.
Not all vision problems can be corrected with contact lenses, but people should consult their optometrist or ophthalmologist if they would like to change from bifocals to contact lenses. Because visual acuity can change over time, people should have their eyes checked at a minimum of every two years.