Computer vision syndrome

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Some possible ways to alleviate eye strain due to CVS
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  • Updated.jpg This entry is out of date, and will not be updated July 2017


See also Print vs. electronic book technologies | Information technology topics | iPhone5 for physicians | Wearable computers

Computer vision syndrome (CVS) is defined as "...a group of eye and vision-related problems that result from prolonged computer use. Its symptoms include headaches, blurred or blurry vision, neck and back pain, redness in the eyes, generalized fatigue, eye strain, dry eyes, irritated eyes, double vision, polyopia, and difficulty refocusing." In addition to the ergonomic and cognitive issues related to extended computer use in the digital age, the mounting evidence reveals that online readers (those who read from a screen) do not retain information as readily as print readers. The difference has now been demonstrated in the primary grades. Clearly, the Internet has had a huge influence in our everyday communicating, and it has changed how we read and acquire knowledge.

In today's world people read different types of print and digital texts daily, which seem to be reconfiguring our brains (see Wästlund, 2007; Wolf, 2008). The research reported by Jakob Nielsen, an expert on website usability, shows that reading on screens is more tiring and remembered more poorly than reading on paper (How Users Read on the Web). In PNAS, a 2014 study showed that using an e-reader before bedtime "... prolongs the time it takes to fall asleep, suppresses levels of the sleep-promoting hormone melatonin, reduces the amount and delays the timing of REM sleep and alertness the following morning. Use of light-emitting devices immediately before bedtime also increases alertness at that time, which may lead users to delay bedtime at home.

In 2013, Slate and Scientific American both published articles on this topic. In the Slate article was this memorable quote: "...our online habits continue to reverberate in the workings of our brain cells even when we’re not at a computer. We’re exercising the neural circuits devoted to skimming and multitasking while ignoring those used for reading and thinking deeply...". The take home message is that most of us understand and remember text better when read on paper rather than a screen. According to the SA article, even though e-readers and tablets are becoming more popular as these technologies improve, reading on paper has many advantages.Also Keim B. Why the smart reading device of the future may be paper. Wired Magazine. 1 May 2014.

What causes computer vision syndrome?


Computer vision syndrome is caused by our eyes and brain reacting to characters on the screen differently from how they react to characters on a printed page. Human eyes have little problem focusing on most printed material, which is characterized by dense black characters with well-defined edges. Healthy eyes can easily maintain their focus on the printed page. Characters on a computer screen, however, don't have the contrast or well-defined edges described above. Consequently, these characters (pixels) are brightest at the center and diminish in intensity towards the edges. This makes it very difficult for eyes to maintain their focus and remain fixed on these images.

According to the American Optometric Association (AAO), CVS is a growing problem due to the ubiquity of workplace computers and mobile devices. Many of the symptoms experienced by computer users, however, are temporary and subside after stopping computer work. Some individuals experience continued reduced visual abilities such as blurred vision, and other problems related to eye strain. When nothing is done to address the cause of eye problems, symptoms continue and worsen. Prevention or reduction of vision changes due to computer usage involves taking steps to control lighting and glare on your computer screen, establishing optimal working distances from the computer screen and maintaining proper posture.

If you experience vision problems (or eye strain) and believe that they are due to working with computers, you are advised to visit your family doctor for a referral to an optometrist. Even minor vision problems should be properly addressed if they do not resolve on their own after rest and time away from staring into computer screens.

Will a glare screen help?

Glare screen filters will help somewhat, but they do not solve your computer vision problems completely. These filters affect glare from the computer screen but not the visual problems related to the constant refocusing of your eyes as you work in front of a computer screen. Once your eyes can focus clearly at the plane of proper distance on the computer screen, they experience relief from the fatiguing effects of staring into a computer. Anti-reflective coating is recommended for all computer eyeglasses. The coating prevents glare and reflections that interfere with focusing on the screen.

If you work in a brightly lit office, you may benefit from a light tint applied to your computer lenses. This cuts the amount of light that reaches your eyes and provides relief in some cases. But tints and filters don't address the underlying cause of computer eyestrain.


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