A study by researchers at a Madrid university which found that LEDs can be damaging to retinas has sparked a fresh health scare.
Dr. Celia Sanchez Ramos of Complutense University, who has been investigating what’s known as the ‘blue light hazard’, predicted ‘an epidemic’ of retina problems due to increased exposure to LED lighting.
The story has been picked up by the mainstream media, including the Daily Mail, which used the headline ‘Do ‘environmentally friendly’ LED lights cause BLINDNESS?’ on its homepage and illustrated the piece with a Philips MasterLED lamp.
Sanchez Ramos has been widely quoted warning of the dangers of LEDs in lighting and in computer, mobile phone and television screens.
‘This problem is going to get worse, because humans are living longer and children are using electronic devices from a young age, particularly for schoolwork, instead of paper,’ Sanchez Ramos said. ‘Eyes are not designed to look directly at light -- they are designed to see with light.’
LEDs expert Dieter Lang of Osram warned the lighting industry of the hazards of blue light from LEDs at an international conference in London last year. He said shorter wavelength light can damage the retina if it is too intense, and outlined ways for luminaire manufacturers to assess and mitigate these risks.
But the effect of blue light goes further, because of the way it guides our bodily rhythms.
PhotonStar’s Fenella Frost, also speaking at the Lighting Fixture Design conference, shared some dramatic examples of the effects of blue light (specifically at 460nm) at the wrong time of day. In studies on mice, the mice gained weight, were more likely to get cancer, and in one study lived for half as under natural daylight.
But even light sources with a warm colour temperature can include high levels of blue, so using warm light later in the day doesn’t necessarily solve the problem.
The issue of LED health hazards and their reporting in the media has sparked a furious on-line debate in the lighting business, with opinion sharply divided on the industry’s Lighting Talk discussion board on both how to react to stories about retina damage and the effects of LED lighting on hormones such as melatonin, and the circadian rhythm.
The warning bells were sounded by a French government watchdog in 2011, which reporter that the blue component of LEDs can be harmful to the eyes of vulnerable people and children.
The French Agency for Food, Environmental and Occupational Health and Safety (ANSES) said that long-term exposure to light at the blue end of the spectrum – especially light from LEDs – can cause ‘toxic stress’ to the retinas. A photochemical change in the eye – related to the amount of retina exposure to blue light – can result in what’s termed cellular oxidative stress, said the authors of the report.
Vulnerable groups include children, those with high photosensitivities, and those who work in high lux levels.
The report also criticised LEDs for their high glare. It pointed out that, because LEDs are point sources, they are more liable to exceed acceptable glare limits. It recommended that the Unified Glaring Rating should be dropped for LED sources because it is unsuitable.
The issue is set to be discussed again at this year’s Lighting Fixture Design conference, which takes place on 5 and 6 June in London.
Lighting Fixture Design conference 2013
Lighting Talk discussion group
Photo: Copyright James Jordan