How can you avoid eye strain caused by computer work?

The eyes of Visual Display Unit (VDU) workers are placed under great strain. All these hours spent peering into a screen can be exhausting. In addition, they work in light, dark, humid or dry environments. This may result in headaches, itchy eyes and a blurred vision. What causes these symptoms, and which practical actions can you take to alleviate them?

Excessive strain on the eyes increases the likelihood of symptoms such as headaches and watery or bloodshot eyes. How much such a strain will impact individuals is rather personal since some people are more resilient than others. Plus, not everyone has an equally perfect eyesight. External influences, such as light, viewing distance and humidity, will also play a role.

Light: the 1-3-9-rule

Depending on how much light falls on the eyes, small muscles cause the pupils to dilate or constrict. If these muscles need to work hard, they get tired. Extremely bright or dark workplaces are not a good idea anyway. But great variations in light intensity also place the eyes under strain.

For this reason, it is important for the lighting conditions to remain more or less constant when the viewing angle changes. In this respect, the 1-3-9 rule is very useful. It sets a light intensity ratio based on three areas in the field of vision: the central zone, the zone just around it and the periphery. To minimise eye strain, the second zone should not be more than 3 times, and the periphery not more than 9 times brighter or darker than the central zone. This saves the pupils from having to adjust constantly, which in turn reduces visual fatigue.

What can you do about it?

  • As an employer, you are legally required to provide adequate lighting for your employees.
  • Adjust the brightness of the displays to the office environment. If employees are using two screens simultaneously, these should be set as bright as possible.
  • Open or close curtains or blackout blinds to respect the 1-3-9 ratio.

Distance: look beyond the length of your nose

In order to see something close up, the lens of the eye must change shape, getting fatter to form image. As we get older, our eyes strain more in forming that image.

Someone working on a computer looks at a screen from a short distance for most of the day. When your employees are chatting with their colleagues next to them, even if their vision focuses on a different distance, their eyes are still perceiving it as ‘close’. It will take a distance of 6 metres for the eyes to relax.

What can you do about it?

  • Divide the office space in such a way that employees can look far.  Arrange desks so that workers have their backs against the wall and don't place cabinets or plants in front of windows.
  • Inform your employees on the need to look in the distance from time to time to give their eyes a rest.

Humidity: blinking can't hurt

The third factor is simple: when your employees stare at a screen, they blink less. In addition, there is not enough humidity in many office environments. Together, these two conditions can contribute to dry eye symptoms.

What can you do about it?

  • As an employer, you are legally required to ensure a sufficient level of humidity in the workplace, adapted to the physical efforts of your employees and the type of work.
  • Remind your employees to blink, by placing small (playful) stickers on their monitors (for example: make sure your eyes don’t dry up, blink from time to time or wink at a colleague).

What are the optimum working conditions for VDU users? Trust our experts

You can call our experts to conduct an indoor climate study or light analysis . In addition, your VDU workers can optimise their workplace and reduce risks by taking the e-Survey or with the help of the e-coach VDU work online tool.