Computer vision syndrome (CVS) can tax your eyes

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    Louisville Courier-Journal

    Thursday, May 31, 2007

    NEW hEALTH ISSUES

    Computer vision syndrome (CVS) can tax your eyes

    By Linda Stahl
    lstahl@courier-journal.com
    The Courier-Journal



    Webmasters, watch out. BlackBerry users, beware.

    Anyone who spends long hours reading and writing on video screens, big and teeny, can suffer from computer vision syndrome.

    Sufferers experience such problems as:

    • Headaches.

    • Eyestrain and aches inside the eyes.

    • Dry, irritated eyes.

    • Blurred vision.

    • Neck and shoulder pain.

    • Sensitivity to light.

    • Temporary inability to focus at a distance, sometimes called pseudo myopia.

    While computer vision syndrome isn't a diagnosed disease, such as glaucoma, the term is useful for communicating what some patients experience daily, said Kent Daum, associate professor of optometry at the University of Alabama-Birmingham.

    Daum and others who study this syndrome say it's something people can work to eliminate.

    Furthermore, eliminating the discomfort and frustration of computer vision syndrome can improve job performance by reducing errors, improving comprehension and interpretation, and increasing productivity.

    Computer vision syndrome began to emerge in the mid-'80s when computers got popular and by the '90s was recognized as a serious issue in the work environment.

    The eyes react well to most printed material that consists of solid black letters on a white background.

    But on a video display screen, the image isn't as good as printed copy.

    "The blacks aren't as black and whites aren't as white. You can't focus as well, and your eyes get tired quicker," Daum explained.

    The characters on a computer screen, called pixels, are brightest at the center and diminish in intensity toward their edges. This makes it very difficult for our eyes to maintain focus and remain fixed on these images.

    But that's just one reason why computers tax our eyes.

    "The position of a screen is really different than if you were reading a book or newspaper," Daum said. "We are used to looking down to read."

    Jeffrey R. Anshel, an optometrist in California who consults with companies about using computers without straining eyes, said, "Offices were basically designed for paperwork, which means focusing on a horizontal surface, but with computers we have a vertical system and that makes focusing different."
    Small screens

    Now, we not only are challenged by the use of desktop computers and laptops but also by the intense use of tiny-screened electronic gadgets such as PDAs and cell phones.

    These small devices have the potential to accelerate the onset of computer vision syndrome, Anshel said.

    The text of these smaller images is not as clear as on larger screens, and bright light makes the screens fade out.

    "If you read on a park bench or while walking through a brightly lighted store, the screen is washed out, and that tends to make problems more prominent," Daum said.

    The one advantage of handheld devices is that they can be held at a comfortable reading distance and looked down on as you would when reading a book.

    Anshel likes people to think about how Homo sapiens have used their eyes as hunter/gatherers and then as members of the industrial age. Now in the age of information technology, the demands on our eyes have changed while our life expectancy has lengthened.

    Anshel and Daum said some people tend to have worse problems with computer vision syndrome.

    Men and women over 40 have eyes that are less flexible and resilient because of the aging process and thus have more complaints. And women over 40 experience particular problems with dry eyes because, as their hormones decline, their tear mechanisms decline as well.

    To reduce symptoms, people usually must take several approaches.

    Getting optimal reading aids is a first step. Daum said that two-thirds of people who are nearsighted or farsighted or have astigmatism don't have their condition corrected.

    That is a major problem that computer vision sufferers must face.

    Second, they should consider wearing special occupational or computer glasses when working at a video screen.
    Computer glasses

    Anshel said that while people often wear trifocals while working at the computer, their trifocals have a very narrow part of the lens that works when focusing on the computer screen. Thus they end up tilting their head back, which contributes to neck aches and other problems.

    Anshel said lens companies sell "occupational progressives" that have two separate focal points.

    An eye-care professional can prescribe lenses with a top focus that's appropriate for you at your computer. He needs to know the distance of your eyes from the screen, which can range from 18 to 28 inches. The bottom of your computer glasses will be able to focus on reading material, which is usually a distance of about 16 to 21 inches.

    Daum said the only disadvantage is that while you can see the computer and your reading material beautifully, you won't be able to focus on someone standing at the office door.

    You will need a second pair of glasses that accommodate all distances of focusing.

    There are other areas that must be dealt with:

    # Proper lighting and reduction of screen glare.

    # Proper positioning of computer screen.

    # Treatment for conditions that exacerbate computer vision problems, such as dry eyes.

    Your behavior is also important, including getting plenty of rest before intensive computer work and taking breaks.

    "These computer vision problems are real problems, and we can solve these problems," Daum said. "I hope people who are having troubles get their eyes checked first and foremost and work on achieving comfort."

    Generally speaking, you don't have to worry about permanent damage to your eyes, Daum said, but you shouldn't put up with being uncomfortable and frustrated.

    And research is mounting that shows if you don't deal with computer vision problems, your performance will suffer, which could have serious consequences.