So, getting computer glasses can transform the office environment for millions of workers at their workstations. As the glasses correct the intermediate zone of your vision, which is the typical distance (20-24") from your eye to the computer monitor screen, they enable the eye muscles to move from keyboard to monitor and back more easily. This alleviates the CVS symptoms of blurred vision and eyestrain.



Perhaps you are sceptical of the need for specific computer glasses and consider them an unnecessary expense: less emphasis has traditionally been placed on computer-induced vision problems than on the ergonomic layout of the workstation. Buying a pair of inexpensive, single-vision (intermediate) lenses off the rack might, then, seem a good idea.

Unfortunately, as most people who need computer glasses also need their vision corrected in the near, and maybe far, zones as well, ready to wear, single-vision glasses don't usually fit the bill. Nor do cheaper, tinted glasses help presbyopic individuals. The pupil dilation, which results from reduced light entering the eye, can exacerbate the problem of blurred vision and eyestrain.

Let's move now from the cheapest, ready to wear, computer glasses to affordable, but more expensive, eyewear with a greater degree of customization. Lenses can be selected to match the requirements of each eye. This gives you a pair of bifocal reading glasses with the upper area optimized for reading text on your monitor, and the bifocal area set to allow the correct focal distance for the keyboard and desktop.

Customization of the individual lenses, however, is sometimes not enough to prevent 'prism' which occurs when your eye movements are not perfectly synchronised. To overcome this problem, a choice of nose bridges is often made available which realigns the distance between pupils and removes this particular cause of eyestrain.

These "do-it-yourself" computer glasses, which require you to find out your existing "add" prescription for each eye, are stylish and lightweight. They also come with anti-reflective coatings. Not only do these reduce the glare from ambient lighting in the workplace, which adversely affects the eye's ability to focus clearly on the monitor, but they also increase the scratch resistance of the lens.

The best possible solution, of course, is computer glasses made to match the requirements of your exact prescription and workplace setup. Fulfilling these requirements means a visit to your eye doctor and a willingness to pay more for your eyewear. Seeking professional help represents, for most people, the safest option.

The more popular styles are the multifocals, particularly the progressive (no-line) lenses. These have a larger intermediate zone than normal progressives and allow you to see clearly in all zones (near, intermediate and far) at the same time while at work.

However, in occupational progressive lens and lined trifocals, there is a trade-off between a larger intermediate zone and distance viewing. Both will allow you to see adequately in an office environment, but they are not suitable for wear outside the office.

This problem of one pair of glasses for normal use and a dedicated pair for computer use, can be obviated by the use of clip-ons. Provided you are fortunate enough to need two prescriptions only in your lenses (intermediate and near or intermediate and far). You can wear your regular prescription lens in the glasses and the computer lens in the clip.

Finally, there is a question of tinted lenses in computer glasses. Opinions seem to vary on their use in reducing excessive "blue light" spectrum. As we have seen, an ultraviolet coating can filter out much of the blue light which reaches the eye from harsh fluorescent lighting.

The jury seems to be out, though, when it comes to amber-tinted computer glasses. Many sportsmen use them to cut down glare from a bright sun, but, in the workplace, their use is not always thought to be beneficial. Some people believe the resulting cut in light transmission and the concomitant increase in use of the eyes focusing muscles, can aggrevate the very condition - eyestrain - which the tint is supposed to alleviate.

Choose your computer glasses wisely, but if your blurred vision continues, look at your work habits and evaluate whether your working environment is ergonomically sound.