Computer glasses are usually prescription glasses that are designed to worn when doing computer work at home or at work. They can be classified as “task specific” eyeglasses. Included in this type of category are lenses designed for sporting events like gun shooting and protective lenses used for other sports. These type lenses are generally designed for the specific activity or situation. When prescription glasses are designed for computer usage, the lenses are set to focus on the computer screen within a precise range or distance from your seated position - the position that is typical when you use your computer. The distance you work from the screen at work and home may be different so the ability of a specific computer lens to help alleviate eye and muscle strain at home and work is usually strictly limited to the parameters of either work or home (unless they are similar in each place). Also, computer glasses can be made without prescription. These type of glasses block the harmless blue light that is known to cause eye strain and long term eye damage., It is a good idea to wear lenses capable of blocking UV and HEV (high energy visible blue light) when using electronics with screens, like your computer.
The concept behind computer lenses can be applied to other tasks done at fixed distances from objects and devices. For example, playing the piano usually requires the musician to sit at a fixed distance from the keyboard and sheet music rest and this is another example of how a computer type lens can help improve visual performance in a specific task.
Our everyday progressive multifocal glasses or bi/trifocal glasses are not a good match for the best vision when involved in specific activities. Using our everyday glasses in a specific activity or work usually requires the user to tilt head and neck in or out or backward to access the most appropriate visual correction to view through the lenses. This causes neck, shoulder, and eye strain that is largely alleviated by computer and task specific lens designs.
Generally speaking Bifocal and Trifocal lens designs do not provide the best solution for computer and task specific needs because the area of the lens devoted to helping you see is not set to the distances present in your work computer environment. Also, the area of the lens used for near and distant correction is smaller than in computer and task specific lens designs. That is also true of progressive (progressive add lenses or PAL) because the actual area or the lens that corrects for a specific distance is quite small. That said, Progressive lens designs are a good starting point for most computer and task specific lenses with adjustments to widen and enlarge the areas devoted to specific vision needs.
There is no such thing as a perfect computer or task specific lens. Task specific lenses are designed to solve a specific work or sport or avocation problem. No one type of lens is best for every person and individual tastes and ability to acclimate to the lens and the task environment determines the best solution for any individual. With so many possible variables from the environment and the user it is wise to have a specific conversation with your Optometrist or Ophthalmologist to determine the exact prescription required for your circumstances. We have ample evidence to suggest that working with a computer on a regular basis for just a couple of hours a day is very demanding on the eyes and we know that computer glasses tailored to solve specific issues are usually quite successful at alleviating eye, neck, head, and muscle aches and strains brought on by workplace tasks. While ergonomic adjustments can help alleviate eye strain to some extent, evidence is mounting that a properly fitted task specific eyeglass lens an important part of the overall eye care solution.
Because of the potential extra stress on the eyes brought on by repetitive work place activities, eye specialists may suggest more frequent examinations for everyone in these situations, young or old. That only makes sense in the goal of preserving the best sight for you through your life.