Is Computer Vision Syndrome the same as
Visual Stress?

Fact: Computers are the number 1 cause of eyestrain in the workplace.

Computer Vision Syndrome is not the same as Visual Stress, being prevalent to some degree among the majority of people who use the computer for extended periods on a daily basis (see below). For visual stress sufferers, the underlying symptoms will remain after practical steps to remove the causes of CVS have been removed (see anti-glare screens and lighting).

Computer vision syndrome (CVS)

Computer Vision Syndrome is a complex of eye and vision problems that are experienced during and related to computer use, is a rapidly growing repetitive strain disorder affecting up to 90 percent of workers who are using computers for more than 3 hours per day.

Computer eye strain and computer vision syndrome are caused by the way our eyes and brain react to characters on a computer screen. Characters on a computer screen don't have the same degree of contrast and definition as printed text: they are created by combinations of tiny points of light (pixels), which are brightest at the centre and diminish in intensity toward their edges, making it more difficult for our eyes to maintain focus on the images. Instead, our eyes tend to drift involuntarily to a reduced level of focusing called the "resting point of accommodation" (RPA), and then strain to regain focus on the screen. This continuous flexing of the eyes' focusing muscles creates the fatigue and eye strain that commonly occur during and after computer use

The human eye is that of a hunter-gatherer spieces (98% of all humans are born farsighted), and the human body is designed for movement.  Our eye muscle systems are in their most relaxed state when we use our vision for distance objects and space, and it is unnatural for us to maintain a sitting posture for long periods of time.

As a result, working at a computer for a long period of time without breaks can cause unnatural strain and other cumulative negative effects on the user including the worsening of farsightedness, nearsightedness, astigmatism, eye-focusing disorders and poor eye coordination.

Common symptoms of CVS are:

• Eyestrain
• Blurred vision
• Difficulty concentrating
• Headaches
• Red, dry or burning eyes
• Increase in nearsightedness
• Slow refocusing
• Excessive fatigue
• Neck, shoulder and back pain

Causes:

• Extending short distance focusing
• Reduced average blinking time
• Poor lighting
• Poor posture
• Excessive glare

Big Feet and Policemen

I remember an old logic question from my school days: "If all policemen have big feet, is everyone with big feet a policeman?". The answer (like the assumption, of course) is, needless to say, no. It's the same with CVS and Visual Stress: everybody who suffers from Visual Stress is likely to experience Computer Vision Syndrome, but not everyone with CVS is a Visual Stress sufferer. However for the 20% who are, the symptoms are likely to be exacerbated if they are not addressed.