Impact: Essex research leads to safer lighting

The Challenge

The brightness of most electric lighting fluctuates continually, generating flicker which is not always seen, but which can have negative effects on health, including headache, fatigue, eye strain and in some instances, epileptic seizures.  

This is bad news for the individual, but could also have knock-on effects for business in reduced productivity if staff are off work, due to ill health.

What we did

Previously it had been thought that flicker was only harmful when it was clearly visible or when it was relatively slow (at a frequency of less than 200 Hz). But research by Professor Arnold Wilkins, and colleagues from our Department of Psychology, proved that much faster flicker (at a frequency of up to 11,000 Hz) may also be  damaging, even though we may not even be aware of it.

He demonstrated that high frequency flicker can form patterns when we move our eyes and the patterns, which can sometimes be seen, may interfere with how the brain controls eye movements. An example, of this is the LED taillights of cars, which at night may appear as multiple lights, even though in reality there are only two lights.

From this, he was able to determine what needed to be done to make energy-efficient LED lights safer, without necessarily increasing costs for manufacturers.

As he explained: “LED lighting is controlled by circuitry that provides a low-voltage electrical supply from the mains. This means some LEDs fluctuate and some do not, depending on the circuitry.

“It is perfectly possible for lighting circuitry to be designed so that any fluctuation is too fast, or too faint, for patterns to occur, and this has laid the foundation for new design specifications for LED lights that are safer and don’t cause discomfort.”

What we changed

Professor Wilkins research led to the Institute of Electrical and Electronic Engineers bringing out new industry standards for lighting in 2015. These became the Approved American National Standard in 2016.

These standards have led to innovation in lighting design and new regulations making lighting safer.

As a result, companies trading in more than 100 countries, are now producing billions of safer, more energy-efficient LED lights.