The Ergo Corner: Computer Vision Syndrome
These tips will help you avoid eye strain on the line or in the office.
Many computer users complain of eye problems such as dry and itchy eyes, eyestrain, and blurred vision. We now have a new term to describe this problem: computer vision syndrome (CVS).
Other symptoms of CVS include headaches and neck and shoulder strain. The amount of computer use is correlated with the level of discomfort: The longer you’re on a computer, the greater the symptoms.
What is it about computers that causes so much trouble for our eyes? It’s complicated, but here’s the shortened version:
Blink rate. When you’re staring at a computer screen (this includes laptops and tablets), you don’t blink as often as you normally would. This means your eyeballs dry out more quickly when you’re surfing the Web or reading e-mails.
Solution? Blink. A lot. So go ahead and flutter those baby blues (or browns). And if anyone looks at you funny, just tell ‘em you’re keeping your eyeballs moist. If this doesn’t work, artificial tears may be needed to supplement your natural tears.
Screen characters. No, this doesn’t refer to Coyote and Road Runner. Screen characters are the letters and symbols that are displayed on the computer screen. They’re often too small to read comfortably, so we either strain our eyes to see them (and thus develop eyestrain), or poke our heads forward to see more clearly (and thus develop neck and shoulder strain).
Solution? Make the characters bigger. In Web browsers, pressing both the “CTRL” and the “+” keys (at the same time) will increase the font size. In other programs, such as MS Word, there’s a slider bar in the lower right corner that allows you to change the magnification.
Refresh rate. Reading text on a computer monitor is very different than reading the same text printed on paper. Although the image on the monitor may appear static, it isn’t. Photons constantly sweep across the screen, “refreshing” each pixel. This “refresh rate” happens so quickly that we usually never even notice it, at least not consciously. But our eyes are finely tuned to minor changes in brightness and clarity. The eye muscles work very hard to keep everything in focus.
Solution? Give your eyes a rest every now and then. Look away from your computer when you’re on the phone. Get up and walk a few paces, or look out a window. Focus on objects further than 6 feet away. This not only helps your eyes, it gives your whole body a break from that static posture you’ve been holding for hours.
There are several ergonomic factors that can impact the severity of CVS:
- poor seating posture.
- poor screen placement (wrong height or distance).
Pay attention to the physical location of the computer screen, your posture, and the lighting parameters to reduce the strain on your eyes.
What do you think? Have you ever experienced CVS? What are your suggestions for reducing eye strain?
Delia Treaster, Ph.D., is a certified professional ergonomist and writes on various ergonomic issues, drawing on decades of experience in occupational ergonomics. She has been an ergonomic contractor with Humantech, one of the largest workplace ergonomics consulting firms in the United States. Prior to working for Humantech, Delia was an ergonomic consultant for the U.S. Postal Service, a senior ergonomic specialist with Travelers Insurance, and a research scientist at Battelle Memorial Institute. She has a master’s degree in human factors engineering and a Ph.D. in biomechanics from Ohio State University.
E-mails to Delia can be sent to email@example.com.
Editor’s note: “Ergo Corner” is part of a series of guest spots by industry experts that will appear regularly on ASSEMBLY’s blog page. Check back frequently to read more commentaries from Delia, as well as contributions on product testing, automated assembly systems, electronics assembly and robotics.