Does the lighting in your classroom give you a headache? Do the children in your class complain of headaches when they read? It could well be due to the lighting you have installed.

In the past, many schools had fluorescent lighting. This could cause headaches and eye strain because it used to flicker rapidly at 100 times per second.

It’s not something that affects everyone, but around 10-20 per cent of people are sensitive to rapid invisible flicker (particularly those who experience migraines and those on the autistic spectrum).

The flicker gives them headaches and interferes with the control of eye movements, disturbing reading. This issue was caused by the magnetic circuitry used to control the lamps. The lamps created a lightning flash down the tube first in one direction then in the other, twice with each cycle of the AC electricity supply.

Over the last three or four decades, most buildings and most schools (although not all) have since replaced magnetic circuitry with electronic high-frequency circuitry.

Or they may have switched to LED lights instead.

Not all lights are equal

Unfortunately, the recent change from fluorescent lighting to LED lighting has occurred without any adequate control or regulations on flicker levels, and so some LED lights are sold that flicker, some even more than fluorescent lights used to.

Furthermore, there is no way you can tell when ordering. LED lighting that flickers has the same retail price as the lighting that does not. I visited four primary schools in Norfolk recently and every one of the schools had flickering LED lighting.

Regulations are being worked on to address this but will not be ready until later this year.

For now, it means there are still concerns that LED lights are causing headaches and eye strain - and in some cases even impairing reading, as recent research suggests.

A slow-motion solution

If - as a teacher or education leader - you are worried about this, what can you do?

Thankfully you likely own a device that can detect the issue - your smartphone.

Because, while the flicker is too rapid to see with the naked eye, you can use your phone’s video slow-motion function (which can record at 240 frames per second) to see if a light is flickering. Record for a few seconds and play it back - if there’s flicker, it should be quite obvious.

Frustratingly, some of the latest iPhone models don’t show up the flicker because the camera software suppresses it, so if you are the proud owner of the latest model you may want to double-check with an older device or an Android smartphone.

If you do see a flicker, you may want to ask about having the lighting replaced - although given school budgets are stretched in most areas, it may not happen overnight.

Ideally, though, you can stop the problem at source by asking a retailer to ensure what they are selling is flicker-free. Sadly though oftentimes products are advertised as such even when they are not.

It may then be a case of asking the supplier to send you a slow-motion video of the light in operation to prove the claim.

It may feel like a strange request, but given the health issues caused by flickering lights, it’s worth getting it right.

Professor Arnold Wilkins is Emeritus Professor in the Department of Psychology at the University of Essex

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