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Computer specs protect users from effects of strained eyes
People who use computers at work every day may not realise that tired or burning eyes, blurred vision, headaches, or neck or shoulder pains could be symptoms of computer vision syndrome (CVS).
Although CVS is more widespread than carpal tunnel syndrome (injury to the wrist and hand often associated with computer keyboard typing), fewer people are aware of this health hazard, says Craig Page, a director of U Wear, the South African licensee for Hallmark International, which recently launched a protective range of computer eyewear in South Africa.
Page says evidence of CVS - dubbed "the number one occupational hazard of the 21st Century - is well documented.
The US-based National Institute of Occupational Safety and Health (Niosh) reported in 1996 that nearly 88% of all computer users would develop CVS at some time in their lives.
The extent of the problem was confirmed in a report released by the US Bureau of Labour Statistics in 1998, which indicated that over 70% of the more-than 75 million American workers then working on computers every day were affected in some way by CVS.
More recent studies have shown that not only does CVS cause eye discomfort, but it also affects productivity in the workplace.
These studies showed evidence of decreased performance even among computer users who had not reported any symptoms of CVS and could see the screen clearly, says Page.
He explains that users may experience fatigue and eyestrain after long hours in front of a computer because viewing a computer screen is actually different from reading print.
"People with healthy eyes usually have little problem in focusing on printed material, where the writing typically consists of solid black characters with well defined edges.
"Electronically generated characters are made up of tiny dots or pixels and are less clearly defined, forcing the eye muscles to refocus continually and work harder while looking at the screen. One optometrist compared it to the eye doing thousands of push-ups a day."
Many computer users also suffer from dry eyes, especially those who wear contact lenses. When looking at a computer screen, we usually gaze straight ahead, instead of downwards as we do when reading a printed page. This means that more of the eye surface is exposed, so the tear film can evaporate more rapidly, creating a dry, gritty sensation, he explains.
The rate at which you blink also affects how dry your eyes feel.
A study reported in a US medical journal in 1993 said that in a relaxed state, people typically blink at a rate of 22 blinks a minute. When reading printed material, the rate drops to 10 blinks a minute and when using a computer screen, to seven blinks a minute.
Another common CVS symptom is back or shoulder pain, which may be caused by hunching forward or moving the head, neck and shoulders to see the computer screen more clearly.
Often treatment is sought for these symptoms while the underlying cause, eyestrain, is not addressed, says Page.
Excessively bright light within or from outside the building in which you work can also cause eyestrain. To cut down on glare from exterior light, adjust blinds and curtains, and, if possible, place your monitor so that windows are to the side of it, instead of in front or at the back.
Also use fewer light bulbs or fluorescent tubes to reduce interior lighting.
Wearing Hallmark computer-specific eyeglasses with anti-reflective coatings and glare filters aids in protecting against UVA and UVB radiation, and eliminates all glare from the screen.
The colour tint also effectively cuts out blue light and protects against CVS, Page says.
He adds that the range of Hallmark computer readers, initially launched as reading glasses, has recently been extended to offer the same protection from computer screens and fluorescent lighting to people with normal vision, through the development of a Plano or a "nil power" lens.
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