Eye strain occurs when your eyes become tired from activities such as driving or reading for extended periods of time. By far the most common cause of eye strain today, however, is from computer use.
 

This condition is known as computer vision syndrome or CVS, defined as a collection of eye and vision problems directly related to computer use. While eye strain related to computer vision syndrome is usually temporary, if it’s not treated it can cause significant discomfort and lead to reduced productivity and reduced job satisfaction.
 

Why do we get computer eye strain?
A computer screen requires the eyes to subtly but continuously refocus. This is exacerbated when the eye switches to focus on objects in the distance and then back to the screen, giving the potential for eye strain.
 

Eye strain and computer use are also closely related because of the long periods of time that computers are used in an average workday. Such a wide variety of tasks are now performed on the computer, including typing, reading, filing and communicating and this means there are fewer natural breaks for the eye and more risk of developing eye strain. 
 

Working in front of a computer also causes the eye to blink less, which causes the moisture in the eyes to evaporate, resulting in dry eye syndrome.   Looking at a large horizontal screen can decrease blinking further still.
 

What increases eye strain risk?
Not everyone who uses a computer develops eye strain but several risk factors make it more likely:

  • Flickering images: if your screen image tends to flicker rather than stay steady, this can put increased strain on your eyes.
  • Small images: if your screen resolution is too high, objects on the screen become smaller, which means your eye has to work harder to focus on them.
  • Background lighting: if the lighting in your office is too bright, this can cause eye strain. This is a particular problem is your screen is in front of a window on a bright day. Alternatively, if the lighting is too dim, the contrast with the bright screen can also put strain on your eyes, more so if you are switching between reading what is on the screen and looking at paperwork.
  • Distance from the screen: sitting too close to the screen or too far away can cause eye strain.
  • No breaks: Working for long periods of time without taking breaks from looking at the screen increases eye strain.

Other pre-existing eye conditions can increase your risk of developing eye strain. These include wearing glasses or contact lenses to correct another vision problem such as long-sight or short-sight, or if you have a condition such as glaucoma or cataracts.

Recognising the symptoms of eye strain
The symptoms of eye strain as a result of computer vision syndrome can vary, but usually include:

  • Blurry or double vision
  • Burning, sore, or itching eyes
  • Watering eyes
  • Headaches
  • Neck or back pain
  • Increased light sensitivity

Preventing eye strain from computer use
You can do several things to reduce the risk of eye strain that comes from computer use:

  • Adjusting the screen resolution: if you need to lean forward to read the words on the screen, you’re most likely straining your eyes, so decrease your screen resolution in order to make text and images larger.
  • Choosing your monitor type: flat screen monitors cause less eye strain than those with round screens. Larger monitors with a diagonal measurement of over 19 inches will also help reduce eye strain.
  • Adjust brightness: make sure that your screen is bright enough not to have shadows, but not too bright that it’s hard to discern contrast and to read grey text on a white background, for example.
  • Adjust background light: avoid light shining directly on your screen, whether it is from a lamp or sunlight. If you can’t avoid direct light, a shade cover for your monitor can help minimise the glare and reflection.
  • Get cleaning: keep your office or room where your computer is clean and free from dust, which can irritate tear ducts and lead to dry eyes.
  • Assess your screen distance: make sure you’re not too close or too far away from the screen – a generally accepted standard is to have your screen 20 to 40 inches away from the tip of your nose.
  • Assess your screen height: the centre of the screen should be just below eye level so that you don’t have to look upwards to focus, which can increase eye strain. If your monitor height can’t be adjusted, use a chair that can be raised or lowered.