Computer Vision Syndrome and Ergonomics

As technology increases and there is more and more screen time from computers, phones, and tablets; our eyes will be one of several areas in the body that will suffer the price.  Computer Vision Syndrome (CVS) is defined by the American Optometric Association as “a group of eye and vision-related problems that result from prolonged computer use”.  They list the symptoms of CVS as:

  • Eye irritation (Dry eyes, itchy eyes, red eyes)
  • Blurred vision
  • Headaches
  • Backaches
  • Neck aches
  • Muscle fatigue

Many causes of CVS are thought to be from poor ergonomics.  Here are some ergonomics risk factors that might contribute to CVS:

  1. Using a computer screen – Computer screens are made up of pixels which are essentially dots of light.  Dots of light don’t have borders that are clearly defined, making it hard for your eyes to focus on them.  This can lead to eyestrain, more so than reading on paper does.  A research article, “Effects of Display Resolution on Visual Performance” by Martina Ziefle finds that reading performance is significantly better with paper than with screen and that reaction times and visual fatigue increased with lower resolution screens (less pixels per inch).
  2. Glare on your screen – Glare can be caused by direct sources, e.g. the sun shining on your screen; or by indirect sources, e.g. light reflection off of the screen from a light or a window or from a surface such as a desk or a wall.  If you have glare on your screen, you won’t be able to see what you’re working on very well.  This can result in squinting, eye fatigue, and muscle cramping from moving your head, neck, shoulders, and back to avoid the glare.
  3. Screen too dark or too light – It is hard for the eyes to adjust to areas of high contrast.  For example, it would be hard on the eyes to have a really bright screen in a dark room or a poorly lit screen in front of a bright window.  Putting strain on your eyes like this could result in headaches and fatigue.
  4. Sitting too close or too far away from your screen – If you sit too close to your screen, it is hard for your eyes to focus which results in eye strain.  If you sit too far away, you will squint, strain, and move forward to see the screen.  This can result in eyestrain and muscle fatigue associated with leaning forward.
  5. Using too small of a font – Many people work with fonts that are too small for their eyes to see.  When fonts are too small, you will lean forward and strain your eyes so you can see.
  6. Using the screen for too long without a break – If you focus on your screen for a long period of time, your eyes will be strained from looking at the same focal point.  Your eyes need to vary in the distance they look at throughout the day so they get a break.
  7. Using the screen for too long without blinking– Studies show that computer uses blink less when working on a computer than they would normally.  Blinking less results in dry, irritated eyes.
  8. Wearing improper glasses or contacts – Wearing glasses or contacts that don’t allow your eyes to focus properly will result in eyestrain and blurred vision.

Now that you know what can cause CVS, here are some ergonomics tips for avoiding it:

  • Use as high a resolution screen as you can.  Alternate computer work with other tasks to avoid prolonged exposure.
  • Place your screen perpendicular (at a right angle) to the window for the least amount of glare.
  • Tilt your monitor down slightly to reduce glare from overhead lights.
  • Use opaque blinds to block sun from your screen.  Make sure the blinds block out all the sun – rays can creep through the perimeter of the blind.
  • To allow natural light in without glare, used vertical blinds for east/west facing windows, and horizontal blinds for north/south windows.
  • Check surfaces for glare.  Change surfaces to light-coloured, matte surfaces if possible.
  • Adjust your monitor brightness for the type of light you’re in.
  • If you have control over the amount of lighting, reduce the lighting for computer work.
  • Avoid large contrast changes around your screen.  Don’t place your monitor in front of the window and don’t use your smartphone in bright sunlight.
  • Sit an arm’s length away from your monitor.  Sit a bit farther away for larger screens.
  • Look to a far distance beyond your computer monitor (beyond 20 feet) every 20 minutes for at least 5 seconds.  Then close your eyes for 5 seconds to reduce dryness.
  • Increase your font as much as you need to see properly.
  • Get your eyes checked regularly and keep glasses and contact prescriptions updated.  Inform your doctor about your screen habits.
  • Monitor your screen habits.  The more time you spend in front of a screen, the greater your chance for CVS.

Luckily, CVS is not thought to cause any permanent damage to the eyes.  By making the changes above, your eyes should be happy and healthy and back to normal in no time.  Screen time is great, but not when it affects your vision.