Computer Vision Syndrome



  Eye Care

New technology also brings new problems. Looking at a computer screen or video display unit for eight hours or more each day can be pretty stressful. This leads to problems with your eyes as well as with your posture.

CVS is defined as a complex of eye and vision disorders related to near work, which is experienced during or related to computer usage.

CVS is the single largest health hazard related to computer work today. If you are the kind of person who spends most of the time working on the computer everyday, you are likely to suffer from CVS. An estimated 800 million people in the world already do. Ignoring CVS can prove to be very costly, as it is known to cause serious immediate and long-term health problems.

What is Computer Vision Syndrome?
When working on the computer, your eyes move from the screen to the keyboard to your presentation on the table about 25,000 times. While doing this, your eyes are exposed to different intensities and frequencies of flicker of light. To survive this task, your eyes are required to adjust to the flicker of the monitor, accommodate (to remove blurred images), converge (to remove double images) and adapt (to various luminance's) 25,000 times a day approximately.

The strain your eyes are subjected to is equivalent of doing 50 push-ups every minute day-in and day-out. But the ordeal does not end there. Tired and beaten, your eyes are further punished by the harsh glare of the computer screen.

How Soon Does CVS Develop? Because working on a computer is a visually demanding task, often in a compromised visual environment, various forms of discomfort and decreased performance occurs.

1 hour / day 27%
1-2 hours 72%
2-3 hours 85%
3-4 hours 100%

Some of the common symptoms of CVS include:

  • Eye strain (sore eyes or eye fatigue)

  • Headache

  • Blurred vision

  • Slowness in changing the focus of eyes (distance to near and back)

  • Blur in the distance after near work

  • Glare (light) sensitivity

  • Eye irritation (burning, dryness, redness)

  • Contact-lens discomfort

  • Neck and shoulder pain

  • Back pain

The best way to avoid CVS is to take corrective action immediately by designing an ergonomically correct work place. That means proper lighting conditions that do not strain the eye, monitor level slightly lower than the line of vision, arm and palm rests to ease the pressure while typing, and an anti-glare screen if possible.

A few simple rules you can follow to ease the eye-fatigue while working on the video display terminal:

  • After every half hour, break eye contact with the computer display. Look out of the window or just walk around.

  • As the blink rate goes down while working on a computer, lubricating drops can be used to alleviate symptoms.

  • Use glasses that have an anti-glare coating.

  • Maintain a comfortable reading distance from the computer display. Do not peer into it. 2 to 2.5 feet (55-75 cm) is a safe distance

  • See that the lighting in the room is indirect and diffused.

  • A periodic checkup with an eye specialist to monitor any invisible injury to the eyes.

Eye problems

  • Dry eyes
  • Redness or irritation in the eyes
  • Discomfort for contact lens users
  • Eye fatigue

Precautions to be taken

  • For dry eyes, you can use artificial tears to wet the eyes
  • The most convenient position for our gaze is to look a few inches below eye level. When you are seeing at this level the shoulders, neck and eyes are at a comfortable position. Seeing things above eye level means craning your neck and opening your eyes wider than you normally do. Sitting like this through the day and for months or years together will create vision and posture problems. Lower your computer monitor 4-8 inches below your eye level.
  • Blink consciously every five minutes.
  • Take a two-minute break each half hour. Shut your eyes and roll the eyeballs behind closed lids.

Workstation arrangement

  • The monitor must be 20–30 inches from your face. This is considered ideal distance. If the distance is greater or less than this, it could indicate the presence of eye problems or cause problems in vision and posture eventually.
  • The monitor must be straight in front of you. Do not keep it at an angle.
  • The centre of the screen should be 6 inches below eye level.
  • The illumination should be such that the light does not reflect from the computer screen. If bright light from the window falls directly on to the screen, rotate your work station to avoid it. If this is not possible, sadly, you have to tone down the light coming in with blinds or shutters. Similarly with florescent lights. It is good to have your work area well lit but it becomes pointless if the bright lights are going to bounce off the computer screen.
  • Bright lights at the periphery of vision and from directly overhead may also be irritants. Organize the lighting so that the illumination is comfortable for you.

Corrective equipment

  • Computer glasses or spectacles with anti-reflective coatings can be used.
  • Anti-reflective screens can be fitted on to your monitor.

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