- SINGLE VISION
As the name implies, these are lenses providing a single focus. While this may imply simplicity in design, it should be noted that as with all other lenses, they come in a broad range of materials and can include design, tint and coating options that enhance function or appearance.
Perhaps no other lens carries more of a stigma as the dreaded bifocal. In reality, it is a lens that easily allows two prescriptions in the same lens… usually one for distance and the other for near. While rarely used these days, the traditional bifocal offers good vision at an affordable price when the prescription demands a multifocal correction. A more common multifocal lens is the progressive lens.
These are simply bifocals with an added segment for intermediate viewing. Again, progressive lenses are used far more often than this lens design. Occasionally, patients request this lens for computer use, however, a better choice at the computer are the newer “COMPUTER LENSES.”
The progressive lens is the multifocal lens of choice. Not only is it cosmetically better, but it also allows for continuous vision from far to near without having to avoid a separating line found in traditional bifocals or trifocals. Historically, these lenses were plagued by small reading areas and peripheral distortion, but newer “FREE FORM” designs have minimized these problems.
- COMPUTER GLASSES
Computers have changed the way most of us work. We no longer look down to a desk while working. Instead, we look across the desk to a glowing monitor. This changes everything visually. Our increased working distance combined with the elevation of the task off the desk makes traditional multifocals obsolete at the computer. Computer glasses are occupational glasses designed with intermediate viewing at the top of the lens and near viewing below. As a rule, computer lenses work best when combined with an anti-reflection coating.