Computer Vision Syndrome

Computer Vision Syndrome

The prevalence of eye symptoms among computer users ranges from 25-93% as reported by various investigators. Computers have become indispensable in the workplace. The professionals spend increasing amounts of time sitting at their computer work-stations. At the same time productivity is increasing and workers are exposed to working at high speed and to tight deadlines.

The combination of fixed and constrained body postures, work overload and unsuitable workstations can lead to health problems. The most common complaints among computer users are aches and pains in the shoulder, forearm, wrist, hand, back and neck and eye strain.

Clearly a large percentage of computer workers experience eye symptoms and subsequently seek eye care. Computer vision syndrome is that set of eye care. Computer vision syndrome related to near work which are experienced during or related to computer use. These symptoms can include:

  • Head aches
  • Eyestrain
  • Blurred vision
  • Dry or irritated eyes
  • Neck aches
  • Back aches
  • Light Sensitivity
  • Double vision

These symptoms are often a result of a combination of three factors:

  • Your workplace conditions
  • Your working habits
  • Tour visual condition
Discomfort Factors
  • Nature of the task
  • Length of time spend at the computer
  • Reduced rate blinking
  • Lack of coordination between the design of the workstation and the design of the glasses or contact lenses used for the task.

Here are some examples of situations that usually increase user discomfort especially to the eyes.

  • Intense tasks such as games.
  • Tasks with few breaks from the screen.
  • Tasks which require constant looking from the copy to screen such as data entry.
  • Detailed tasks such as desk top publishing or Computer Assisted Design (CAD).
  • Eye level placement of screens causes eyes to be wide open causing faster drying.
  • Eye level screens are too high for most bifocal wearers unless they have specially designed glasses for this task.
  • Many glasses exacerbate the restriction of movement which is a consequence of most computer tasks causing neck, shoulder, and arm problems.

The average rate of blinking is 12 to 15 times per minute. This is frequently reduced during intensive tasks, leading to visual fatigue and dry eyes. Therefore, reading from a screen reduces blinking, which in turn, leads to discomfort.


Good lighting design can significantly help reduce discomfort due to glare. Light leaving the fixture can be directed so that it goes straight down and not into the eyes of the room occupants. This is most commonly accomplished with the louvers in the luminaries or fixture. An even better solution is indirect lighting in which the light is bounced off the ceiling - resulting in a large low luminance source of light for the room.

When you sit, the weight on your lower back is one and a half to two times bigger than when you stand. A good chair must accommodate your body sizes and must be adjustable in the following areas:

Height of the seat

When your feet rest comfortably on the floor, a 90 degree angle between upper and lower legs is desirable. In this position, your upper legs are virtually horizontal.

Depth of the seat

The clearance between the front edge of the seat and the back of your knee must fit a clenched first.


The backrest must support the area from the upper ridge of the pelvis to the shoulder blades. The curve in the backrest must support the hollow in your lower back. An adjustable tilt is desirable.