Occupational lenses are multifocal lens which are designed to be suited in certain hobbies or jobs. Glasses that have these lenses are also known as special-purpose glasses or eyewear and they are not made for everyday wear.
Double-D Bifocal
This has a flat-top D-shaped bifocal on the bottom part of the lens. Aside from that, it has a flat-top near upside-down segment at the top portion of the lens and the rest of the lens has distance correction.
This is designed for those people who have certain jobs such as auto maintenance and office works. They are the ones who will highly benefit from this type of lens because it allows them to see well in close distances.
E-D Trifocal
It has the distance correction on the top half part of the lens. Aside from that, it has an intermediate correction at the bottom half part of it. This is a great choice especially for those who needs wide view but also wants to see clearly at close distance. This a good candidate for those people who need to keep an eye of a wide area at close distance such as those who are working as a television production person.
For those who are Reading All Day at Work
In some cases, a common multifocal lens can be an occupational lens just by changing the position of the near and intermediate segment of the lens. A good example for this is buying a separate pair of eyewear or glasses that have trifocal or bifocal segments if your job needs to read much each day. This will allow you to use the computer or read for a longer period of time without the need of being in an uncomfortable posture just to see clearly.
You may also want to consider buying office progressive lenses which have wider, larger intermediate zone for computer usage and smaller zone for far or distance vision. These lenses can provide a more usable vision for your desk and computer work while still offering adequate distance vision.