Staring at a computer screen for hours at a time won't ruin your vision, but after a while it can produce tired, scratchy eyes, loss of focus, dry eyes, neck and shoulder pain or headaches. In addition to the physical discomfort, there can be a loss of productivity, eye experts in Durango say.The condition is called computer vision syndrome, known as CVS in the industry.
"It's an artificial strain because in a relaxed position the eyes focus 20 feet away, which is like standing with your arms at your sides," said optometrist Mark Miller at High Country Optical. "But concentrating on a computer screen 18 to 30 inches away strains the convergence muscles and focusing mechanism. It's like holding your arms out from your sides like a bird."
Optometrist Lee Ann Hoven at Advanced EyeCare said continually focusing and refocusing on the characters on the screen tires the eyes.
"Computer-screen characters don't have the contrast or well-defined edges like printed words," Hoven said. "So your focus can't remained fixed."
An optical industry group, The Vision Council, estimates that 140 million Americans use a computer at work. Nearly 90 percent of those who are on a computer at least three hours a day suffer eye strain.
Temporary relief for computer-induced eye strain can be found through techniques such as:- Tilting the screen so it's 15 degrees below the line of sight. Looking up requires more muscle than looking down. Also, the glare is less if the screen tilts down slightly.
- Making sure the work station has proper lighting.
- Blinking to activate the glands that wet the eyes, which tend to become dry from lack of motion when the eyes focus on the screen.
- Resting the eyes by looking across the room or out the window every 10 to 15 minutes. Limit yourself to a 20-minute maximum for looking at the screen in one stretch.
- Getting up and moving around for a few minutes every hour.
Miller recalled that computer eye strain was being discussed when he graduated from optometry school in 1996 but it wasn't yet known as CVS. Now, optometrists recommend special glasses for CVS.
Hoven said it's difficult to find a single lens that's good for driving, reading and working on the computer. "Typically, glasses for computer work are calibrated for the distance from eye to screen, are tinted and have an anti-reflective coating on both sides of the lens."
Hoven said Advanced EyeCare uses a laboratory in Salt Lake City to make prescription lenses. But the company also buys lenses from companies with proprietary lens formulas such as GUNNAR Optiks or the PRIO Corp.
Tracy Henderson at Eyewear Durango, a distributor of GUNNAR Optiks lenses and frames, said timely attention to troubled vision is important.
"If you address the problem early, it won't become a syndrome," said Henderson, a 24-year optician certified by the American Board of Opticianry.
Henderson said GUNNAR Optiks can make prescription readers or a "progressive" lens that's allows users to work on the computer, read material on the desk and walk around the office.
Miller said the choice of prescription glasses or simply readers adapted for computer use depends on the individual.
Some people can find glasses that serve for general use as well as computer work, while others will need a pair for each use.