When you undertake a particular job, you may need occupational lenses, which are not designed for everyday wear. Occupational bifocals and trifocals are made for specific jobs. These special-purpose eyeglasses are specifically suited for work situations. By placing the near, intermediate and far vision zones on certain areas of the lens, specific jobs are made easier.
Anyone over the age of 40 who needs multifocal lenses can benefit from having a second pair of glasses just for work purposes. Here are the different types of occupational lenses and what they’re used for.
The Double-D Bifocal
The Double-D bifocal is perfect for reading and overhead near work. It consists of a D-shaped flat top bifocal at the bottom of the lens and an upside-down flat top near segment that’s located at the top of the lens. In between these two sections, the lens is for distance correction.
If you work in an occupation such as auto maintenance and repair, you could benefit from a Double-D occupational bifocal, as it allows you to be able to see well close up, whether you’re looking down or whether you’re looking up to work on a car on a lift.
Other occupations, such as mail clerks, who read documents and may need to file them overhead, might also find this lens useful for work.
The E-D Trifocal
When you need to see everywhere, especially at arm’s length, you need the E-D trifocal, which has the distance correction in the top half of the lens and an intermediate correction for vision at arm’s length in the bottom half of the lens.
As with an Executive bifocal, the line separating these two zones extends across the entire width of the lens. The difference is, E-D trifocals have a small D-shaped segment for near vision embedded in the intermediate zone.
E-D trifocals are an excellent choice for anyone who needs a wide field of vision at arm’s length, but also needs to see well close up and at a distance. A good candidate for these lenses would be a television production person, who must keep an eye on several TV monitors, read notes from a clipboard and still be able to see someone across the room.
Reading all Day
If your work requires you to read all day, you may want to consider a separate pair of glasses that have the bifocal or trifocal segments placed higher than normal in the lens. This would enable you to read or use your computer for extended periods without having to tip your head back in an uncomfortable posture. A common multi focal can become an occupational lens by simply changing the position of the intermediate or near segment of the progressive design.
You could also try an “office” progressive lens that has a larger, wider intermediate zone for computer use and a smaller zone for distance vision. These occupational lenses give you more usable vision for computer and desk work, but still provide enough distance vision for seeing people across the room.
Because the distance zone of occupational progressive lenses is limited, they’re not suitable for driving or other tasks that require a wide field of vision for distance.
