Vision Over 40

Bifocal lenses are divided into two powers, one for distance vision and the second for near vision. Bifocals are created in a variety of designs with different sized and shaped viewing segments for near and far vision. While bifocals provide good distance and near vision, they are lacking in corrective power for intermediate areas, which is what has led to the development of trifocal and progressive lenses.

Trifocal lenses provide an additional lens power zone for intermediate vision (which is typically about an arm’s length away).

Some people are bothered by the visible lines where the lenses are divided in bifocal and trifocal lenses. In addition to aesthetics (the lines have become a sign of presbyopia which many associate with growing old), the harsh divisions in the zones can cause a distortion in the object you are viewing (an image jump) when you switch your gaze from one power to the next.

The most popular type of occupational lens is the Double-D lens. The lens is divided into three segments, with the top designed for intermediate vision, the bottom segment for near vision and the rest for distance. This design is ideal for people who need to see close both when looking down (to read something) and when looking overhead. Professionals that frequently use Double-D lenses are auto mechanics (who have to look overhead when under a car), librarians, clerks or office workers, (who have to look at shelves overhead) or electricians (that are often involved in close work on a ceiling). They are called Double-D lenses because the intermediate and near segments of the lens are shaped like the letter “D”.

As opposed to Double-D lenses which have the majority of the lens for distance vision, E-D lenses focus on intermediate vision with an area for distance on the top and for near vision on the bottom. These are ideal for individuals who are working at about an arm’s-length away the majority of the time, such as on a multiple computer or television screens, but frequently need to look up into the distance or close to read something. The “E” in the name stands for “Executive Style” which represents the division between the top distance vision lens and the bottom intermediate vision lens which goes all the way across the lens. “D” in the name of the lens is due to the fact that the near section in the bottom of the lens is shaped like a “D”.

Multifocal lenses designed for office work provides the largest section with an intermediate lens designated for viewing the computer screen and a smaller area for limited distance vision. You can have progressive or trifocal lenses that incorporate near vision as well.

That’s right, there are even specialized lenses made for golfers! Golfers need to see a wide range of distances during their game from their scorecard, to their ball on the tee, to hole far away to line up their drive. In these lenses, the close segment is small and placed on an outer corner of one lens, to allow for brief close vision but not interfere with the distance game. Usually, right handed golfers will have the lens on the right side and vice versa.

Standard progressive lenses must fit to your vision needs. They can be added to frames of your choice, but you need to ensure that the frames are the right width and height proportions to grant enough space for the gradient changes in the lens. Otherwise only a small area will remain for the distance or near vision zones.

To overcome the issue mentioned above, there are now progressive lenses called “short corridor” lenses made to fit into smaller frames to suit a wider range of eyewear styles.

Also known as “near variable focus lenses” or “office lenses”, these specialized PALs are designed specifically for computer users and other occupations that require strong intermediate and distance vision. For computer users that work at a computer for many hours, these lenses will help to reduce eye strain, eye fatigue and other symptoms of computer vision syndrome that come from looking at a computer for extended periods.

Single vision (as opposed to bifocal or trifocal) reading glasses come in two lens styles – full and half. Full readers offer a uniform magnification (the entire lens is the same focus) and you need to remove them to see clearly at a distance. These are ideal for individuals that spend a lot of time reading and don’t often have to look up during that time. Half readers are also uniform magnification but offer smaller frames that allow you to look over the lens when you want to see further away rather than removing the frame from your face.

Bifocal reading glasses offer two zones of vision within one less. The upper part of the lens allows for distance vision, while the lower part is for reading. Bifocals have a visible line across the midline which divides the two zones. You simply look into the part of the lens that offers the vision you desire.