Saturday, 23 July 2011

Computer Use & the Eyes

Published in "Panorama"

Working Safely with Computers

The paper-pen culture is being speedily replaced by the computer culture as evidenced by the increasing number of households and workplaces throughout the world that are hooked to it. There are associated health problems, more in the nature of irritations, discomfort, fatigue and consequent slackened efficiency at work. The commonest problem relating to increased use of computers for prolonged periods of time is eye strain leading to eye fatigue. Computer Vision Syndrome (CVS) is the name given to eye problems caused by prolonged computer use. Office workers have their share of computer-related hazards which include stiffness of and pain in the neck, back and shoulders.

The question foremost in the minds of computer users and parents in particular, is, Does the computer harm the eyes? Says Dr.Azim Siraj, Eye Surgeon and Specialist, Prime Medical Centre, “Various studies reveal that radiation emitted by computer monitors is minimal and hence not any cause for concern. In fact, these studies show that the ordinary tube light which we use in our homes, actually emits some amount of ultraviolet light which is more than what the video display terminal (VDU) of the computer does!”

Well, having said that, why is it that we get eye strain from computer use? That’s basically because we are exposing ourselves to light and to constant viewing of objects at close range, explains Dr.Azim. The strain itself is a result of a combination of factors which include using the computer for long periods of time, maintaining faulty posture while working on them, improper position of the computer itself, poor lighting, lighting that produces glare or reflections, fuzzy images or images which are too dim or too bright, reduced rate of blinking which results in eyes becoming dry from insufficient lubrication.

Elaborating on this aspect Dr.Azim explains, “When you are sitting in a particular posture and constantly gazing at a particular thing, you tend to blink less than the normal blink rate of 8-12 per minute. This means that your natural tears are not able to lubricate your eyes as normal, leaving you with 'dry eye' symptoms. When your eyes feel dry, you tend to rub because of the itching and gritty feeling. This increases the chances of infection from our hands.”

We find most computer users wearing glasses. Does this mean computer use leads to this phenomenon? Dr.Azim explains, “The eye has got a focusing capability. So when we are looking more at a close object for a long period of time without looking at distant objects at all, the eye muscles being more exposed to the short range, get locked for near vision. Hence when we try to see distant objects, the eyes take sometime to relax. For some people, it might not relax at all! Any person who has got locked for near vision and cannot see distance, is a short sighted person. The greater their exposure to near vision alone, it becomes a vicious circle and they require glasses for distance. This may possibly be one of the causes of myopia but it has not been conclusively proved so by research.”

What are the symptoms of eyestrain? The most common symptoms include red, watery, irritated eyes, tired, aching, or heavy eyelids, burning and gritty feeling in the eyes, problems with focusing, headache, backache, blurred vision and sometimes double vision or after images. Other symptoms of CVD may include temporary myopia, the inability to focus clearly on distant objects for a few minutes to a few hours after using the computer and increased sensitivity to light.

Although CVS has not been found to cause any permanent damage to the eyes, its painful symptoms can affect performance at work and home. Besides relaxing the eyes at periodic intervals, good posture is the foundation of correct computer ergonomics. Prevention of computer related problems requires modifying the work environment by making certain adjustments to the lighting, seating, placement of computer monitors, keyboards, to promote postures that avoid continuous stress on any part of their bodies.

1. Main important aspect of posture requires adequate support for the back such that the back is not bent while working. Sit flush against the back of the seat.
2. The height of the seat from the floor should be exactly the distance between the sole of your feet and knees.
3. The keyboard should be positioned so your wrists and lower arms are parallel to the floor. That is, if you take a side view, your elbow should be at right angles with respect to the keyboard.
4. Try to keep the computer screen two feet away from your eyes.
5. The monitor should ideally be placed below eye level, so that your eyes look down and the neck is slightly bent down. The monitor should look up into your eye by around 10-15 degrees, so that you look down and your eye is relaxed. Looking up to the monitor will cause you a stiff back.
6. Constant shifting of vision from document to keyboard to the computer screen, particularly if you are not skilled in typing, will cause neck, back and eye strain. Hence position all reference material as close as possible to the screen to minimize head and eye movements and focusing changes. This is particularly helpful for people working on data entries.
7. Anything bright will cause eye strain; hence you should look at a reasonably dull background so that the contrast between the background and on-screen characters should be high.
8. Most offices are closed spaces with hardly 10 feet around. An eye relaxes only if it looks beyond 20 feet. Computer users should take a break every half an hour or 45 minutes, to peer from a window to view a distant object for at least 3-4 minutes. This is particularly important for short-sighted people. This also causes the eyes to blink and lubricate themselves.
9. Don’t keep scrolling down the screen without breaks. Consciously pause, blink at least twice and continue the scrolling so that the eye is kept moist and will not head towards dryness and fatigue symptoms.
10. Those sitting at the computer all day should stand up, move about, and exercise frequently. Sitting, stretching, and doing joint rotation exercises can help reduce eyestrain.
11. Glare on walls, reflections on the computer screen and excessively bright light can cause eyestrain. Ideally the light source should be either right on top of your monitor or behind it. Also diffused lighting with low intensity bulbs is best. There should be no reflections on the screen from overhead lights, windows or desk lamps.
12. Clean the monitor surface periodically because you find most computer terminals full of finger stains and static dust. So you are seeing through a dull medium which is a strain on the eye.
13. Any windows should be at right angles to the computer screen, rather than behind it or in front of it.
14. If you wear glasses or contacts, make sure the correction is right for computer work.
How does the use of anti-static coating, that is, an additional dark screen, on computer monitors, help? Dr.Azim explains, “These don’t work by cutting off radiation because in any case the radiation from computers is not high. But these screens help by enhancing the contrast and making it comfortable for the eyes.”

How do you ensure you don’t suffer from eye strain? Dr.Azim advocates consultation with an ophthalmologist or eye specialist “If you have frequent headaches, blurred vision for distance, double vision, tired, dry or burning eyes, eye discomfort for long periods or if you have increasing difficulty reading small print.”

Explaining the prevention aspect Dr.Azim emphasizes, “For people without glasses who may or may not have the symptoms of eye strain, complete eye check up once a year is advisable. For wearers of glasses, this is a must every year though it does not necessarily imply their glasses may be changed every year!

Can there be any complications from untreated eye strain? “If the dryness is severe and prolonged, it can cause eye damage, but this kind of damage is more common in dryness caused by other pathological diseases, infections, trauma and chemical burns,” assures Dr.Azim.

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