LED lights can permanently damage the retina and disturb natural sleep rhythms, France's government-run health watchdog has said.

The French Agency for Food, Environmental and Occupational Health and Safety (ANSES) warned powerful LED lights are 'photo-toxic'.

In a 400-page report, the body cautioned it can cause an irreversible loss of retinal cells and lead to a common cause of blindness.

ANSES urged officials to revise the maximum limit for exposure to LED lights, which emit 'blue light' at much higher quantities.

LED phone, tablet and laptop screens do not pose a risk of eye damage - but the intense bulbs used in car headlights may, it suggested.

The French Agency for Food, Environmental and Occupational Health and Safety (ANSES) warned exposure to an intense and powerful LED light is 'photo-toxic'

The report distinguished between acute exposure of high-intensity LED light, and 'chronic exposure' to lower intensity sources.

While less dangerous, even chronic exposure can 'accelerate the ageing of retinal tissue' and contribute to poor vision, the agency said.

Long-lasting, energy efficient and inexpensive, LED technology has gobbled up half of the general lighting market in a decade.

And industry experts predict its share will continue to rise, topping 60 per cent by the end of next year.

LED uses roughly a fifth of the electricity needed for an incandescent bulb of a comparable brightness.

The basic technology for producing a white light combines a short wavelength LED such as blue or ultraviolet with a yellow phosphor coating.

HOW CAN YOU REDUCE YOUR BLUE LIGHT EXPOSURE? USE a blue light filter on your phone, tablet or computer to shield skin and eyes at night, advises Dr Alejandro Sanchez de Miguel, a postgraduate researcher at the environment and sustainability institute at the University of Exeter. APPS which filter blue light towards the evening include f.lux for your computer and phone. Others such as Twilight or the ‘night mode’ setting on your device will reduce blue light emitted at any time. EVERYONE should wear factor 50 suncream with five-star broad spectrum protection, to block UVA and UVB light, as well as iron oxides, which protect against blue light, says Dr Andrew Birnie, a consultant dermatologist and skin cancer specialist at the William Harvey and Kent and Canterbury Hospitals. VITAMIN C serums can also provide antioxidant protection against blue light, says consultant dermatologist Dr Emma Wedgeworth. AVOID using your phone or PC in the dark, as your pupils will dilate and take in more blue light, says Dr Ajith Karunarathne, an assistant professor in the University of Toledo’s department of chemistry and biochemistry. Advertisement

The whiter or 'colder' the light, the greater the proportion of blue in the spectrum.

LEDs are used for home and street lighting, as well as in offices and industry. They are also increasingly found in auto headlights, torches and some toys.

LED phone, tablet and laptop screens do not pose a risk of eye damage, Francine Behar-Cohen, an ophthalmologist, said.

He explained they have a lower risk because their luminosity is very low compared to other types of lighting.

But these back-lit devices - especially when they are used at night or in a dark setting - can 'disturb biological rhythms, and thus sleep patterns'.

Because the crystalline lens in their eyes are not fully formed, children are particularly susceptible to such disruptions, the ANSES noted.

Interfering with the body's circadian rhythm is also known to aggravate metabolic disorders such a diabetes, as well as cardiovascular disease and some forms of cancer, noted Dina Attia, a researcher and project manager at ANSES.

In addition, a stroboscopic affect in some LED lights - provoked by tiny fluctuations in electric current - can induce 'headaches, visual fatigue and a higher risk of accidents,' the report said.

For domestic lighting, ANSES recommended buying 'warm white' LED lighting, limiting exposure to LED sources with a high concentration of blue light, and avoiding LED screens before bedtime.

ANSES also said that manufacturers should 'limit the luminous intensity of vehicle headlights', some of which are too bright.

Finally, the agency cast doubt on the efficacy of some 'anti-blue light' filters and sunglasses.

The UK's chief medical officer Dame Sally Davies has previously said blue light is an 'important area of investigation'.