A multifocal lens that has a specific purpose, or is created to perform a specific job, is called an occupational lens. What makes these lenses different from other lenses is the fact that the near, intermediate and far zones for vision are placed on specific areas of the lens, which makes vision for these particular tasks easier. These lenses are found in glasses that are not for everyday wear.
Double-D Bifocals are special bifocals designed for reading and overhear close work. This type of bifocal is especially helpful for auto workers, who need to see close things, both overhead and when working on a car on a lift, and when looking down. The lens is built with an inner circle for distance sight, and an outer circle for near vision. Office workers who need to file documents overhead might also find this lens very beneficial.
E-D Trifocals are made for people who need to see at arm’s length distance most of the time, and near and far some of the time. The E-D trifocal is made for someone who does most of his or her work at arm’s distance. For example, someone who needs to be monitoring several screens at once, like someone who works in video. At the same time this job would entail periods of reading, and recognizing people entering a room. The E-D trifocal accomplishes all of these tasks. The lens has a distance correction section in the top of the lens, and an intermediate correction section (for seeing screens) at the bottom. A small portion of the lens, shaped like a D, is embedded in the bottom zone, within the intermediate section.
If you need to read all day for work, or view a computer screen, your eye doctor can create an occupational lens for your needs by moving the position of the intermediate and near sections of the bifocal lens, or change the design of the progressive lens.
If you need glasses for reading most of the day, you may need a pair of glasses that will work better for reading for long periods of time. Glasses that have the bifocal or trifocal portions placed higher on the lens may help. Glasses with a reading sections placed higher will enable you to read comfortably for longer periods of time.
Another option is an “office” progressive lens. This type of lens has a wider and larger intermediate portion of the lens for looking as a computer screen, and a smaller section for distance. An “office” lens gives you a larger lens for office work, such as reading and computer vision, and also provides enough lens space to see distances when needed. These lenses are for office only, and not daily life, because they don’t give enough distance vision for many every day tasks, including driving.
Multifocal lenses can be a problem for golfers when they are on the golf course. Because of the placement of the near zone, it can be hard to see the golf ball without having to tilt your head uncomfortably. It is also difficult to line up a putt with regular multifocals.
A “golfer’s bifocal” is the answer to this problem. A “golfer’s bifocal” lens consists of a distance lens, which a small round near portion placed on the bottom outside corner of one lens. This allows you to read when needed, and gives you a wide view for golfing.
Most adults over 40 can benefit from having more than one pair of glasses. If you wear multifocal lenses, there is a good chance you can benefit from a pair of occupational glasses designed for your specific needs.