Computers and the Eye

Computers are used by many people at work. Computer eye strain has become a major job-related complaint. There are a set of symptoms that occur among computer users. These include decreased vision, burning and stinging and sensitivity to light. These symptoms have been called Computer Vision Syndrome (CVS).

Frequency of CVS

Various studies have shown that between 25 % and 93 % of computer users get computer vision syndrome.

The cause of CVS

Several factors may result in this syndrome. They may be environmental, personal or a combination of both.

Environmental factors

The angles at which users look at the computer screen, and the amount of light in the area of the computer is important. If there is low humidity in the room it may make the symptoms more severe.

Personal factors

If the eye sight is not corrected with the right eye glasses it may result in CVS due to fatigue. Middle aged and older people have presbyopia – which means they cannot adjust their focus quickly. They sit at the wrong distance from the screen to be able to see correctly.
Working for a long time at the computer will make patients with dry eyes feel it more acutely. This is because they do not blink often enough. Normally patients blink 18 times per minute. Computer users blink only 4 times a minute therefore the tears dry up faster and are not produced quickly enough.

10 steps to reduce computer eye strain and the symptoms of CVS

1. The eyes should be properly tested.
   A routine eye examination can identify refractive problems that could lead to eye strain and discomfort. The patient should tell the optometrist how often and long computers are used at home and at work
2. There should be proper lighting
   If it is too bright from outdoor sunlight coming into the room or from harsh interior light, eye strain can develop. When using the computer, the light should not be about half that found in most offices. Close the curtains or blinds to block out the light from outside or use lower intensity light bulbs. The computer should be positioned so that the windows are at the side instead of in the front or back.
3. Minimize the glare
   Glare on walls as well as reflections on the computer screen can also cause computer eye strain. An anti-glare screen can be installed on the monitor to avoid the glare.
4. Upgrade the computer screen
   Old tube-style monitors can be replaced by flat panel liquid crystal display (LCD), like those on laptop computers. These LCD screens are easier on the eyes and often have an anti-reflective surface. Old screens can cause a ‘flicker’ which often is not noticeable but can lead to eye strain.
   A bigger display is easier to read and causes less strain on the eyes
   Adjust the brightness and contrast on the computer screen.
   As a test – if the white background on the screen looks like a light source it is too bright. If it seems dull and grey, it may be too dark. The screen can be adjusted so that there is high contrast between the characters and the background. The text size and colour can also be changed for comfort.
5. Blink more often
   Blinking rewets the eyes to prevent drying out. If dry eyes are persistent problem artificial tears e.g. Optive, Tears Naturale or Teargel can be instilled. Decongestant eye drops that make red eyes white should be avoided as they are not formulated to reduce dryness and can cause rebound redness in the eyes.
   Recommend that, every 20 minutes, patients blink slowly (as if falling asleep) 10 times. This helps to rewet the eyes.
6. Exercise the eyes
   Looking far away relaxes the focusing muscle inside the eye to reduce fatigue. Advise patients to look at an object 20 meters away for 20 seconds every 20 minutes.
   Another exercise is to look at something far away for 10 to 15 seconds, then look at something close up for 10 to 15 seconds and repeat this 10 times. This prevents the focusing ability of the eye to ‘lock up’ after prolonged computer use.
7. Take frequent breaks
   Taking minibreaks during the day helps to reduce CVS and neck, shoulder aback pain. During these breaks advise that the patients, stand up, move about and stretch the arms, legs, back, neck and shoulders to reduce tension and muscle fatigue.
8. Modify the work station
   If the patients need to look back and forth between a printed page and the computer screen, this can cause eye strain. The page should be on a copy stand next to the screen and be lighted properly. Suggest they use a desk lamp that does not shine into their eyes or the computer screen. Ensure that the humidity in the work environment is not too low. This will increase the incidence of dry eyes.
9. Improper posture during computer work also contributes to CVS. The workstation and chair should be adjusted to the correct height. The screen should be about 50 to 60 cm from the eyes. The screen should be a little bit below the eyes for comfortable positioning of the head and neck.
10. Consider computer eye glassesThis can be suggested if the patients wear contact lenses or bifocal or progressive lenses. Contacted lenses can become dry and uncomfortable during prolonged computer work. Bifocal or progressive lenses are often not the optimal for the distance to the computer.

Conclusion

Computer Vision Syndrome can be reduced or eliminated by the adjustment and placement of the computer, proper workspace design, lighting control and good vision care. Symptoms associated with this syndrome may be improved with artificial tears.