This summary of the scientific Opinion on 'Potential risks to human health of Light Emitting Diodes (LEDs)' by the Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) covers some of the Opinion's key points and goes more in depth than the one-page factsheet on the same topic, also available on this website. An abstract and a shorter but more technical summary are also included in the scientific Opinion itself. Information about data and methodology and the science behind LEDs and eye and skin optics are also found in the Opinion and are not covered here.
Navigation
- 1. Background
- 2. Are there any existing safety regulations concerning optical radiation?
- 3. Health risks
- 4. Conclusions
3. HEALTH RISKS
3.1. Is the general public at any risk from exposure to LED screens in TV sets, laptops, phones, tablets and toys?
Studies show that the radiance from screens is less than 10% of the maximum amount that would be within safe limits to still protect the retina from photochemically-induced injury, so the short answer is no. The general public does not risk getting eye injuries from optical radiation exposure from LED screens in normal use. The longer answer, however, is that evaluating the risk is not as simple as it might seem because of the many variables that have to be taken into account. The type of LED light used in screens, toys and car lighting contains blue light, and evaluating the risk of blue light damaging the retina requires considering the integrated radiance of the retinal image from the light source (the reflected glow of the light source seen in the eye itself), or the flux of radiant energy per unit area per unit solid angle. This changes, depending on if the light is looked at momentarily, with the eye looking directly at it for a brief time, or if it is viewed over extended time, when the retinal image is spread out over an increasingly large area of the retina because the eye will not remain fixed and staring at it, but will move around. So in fact, looking at lights longer does not necessarily pose a greater risk, because the eye will normally roam and blink, reducing the radiant energy that reaches each part of the retina.
The blue light component of the optical emission of LED lights is similar to an incandescent lamp, but the infrared emission will be greatly reduced or absent. This might influence the normal bioprocesses in humans and is still being investigated.
3.2. Are there any special concerns about the use of LED lighting in streetlights and vehicles?
Many street lights and other street fixtures now use LED lighting, mainly because it is energy efficient. However, poor quality LED lighting can appear harsh or can induce glare or scattering effects. The brightness of lighting should be appropriate to its use, and LED street lights do not need to be so bright as to replicate daylight, but should provide soft lighting for security and safety. Motorways might require brighter lighting than residential roads as well. The blueness of an optical radiation source like LEDs is often measured by its correlated colour temperature (CCT). The higher the CCT, the more blue-rich it is and the harsher and brighter it appears. However, this metric can provide misleading results for some LED sources.
As good lighting practice, high luminance LED lights should be diffused or shielded from being looked at directly to avoid glare. Some LED street lights have exposed LED elements that can be seen by road users within their normal field of view, such as when they are looking ahead. This may make viewers instinctively look away from the light source if it is too bright or have difficulty seeing the area near the light source.
Vehicle LED lights, particularly daylight running lights and headlights, can be a source of glare. They might also produce more glare when it is foggy. Glare occurs when light is scattered in the eye and it is more common when light sources emit high levels of blue light. This may make it difficult to see things that are near to the light source, especially for older eyes. When glare is so intense that vision is completely impaired, it is sometimes called disabling glare.
3.3. Are vulnerable groups like children and the elderly at any increased risk?
Children have a higher sensitivity to blue light and although emissions may not be harmful, light from blue-emitting LEDs may be very dazzling for young children. Some LED emission spectra may cause light-induced retina damage, which is a concern especially for children below about three years of age. There is, however, a European standard for electronic toys that limits the emission of optical radiation from toys.
Adolescents and teens in general are exposed to LED lights sources for long periods of time, spending time on their phones, tablets and computers, and they may also be exposed to new LED light sources, like virtual reality headsets, where the screen is very close to the eyes. The luminance of the light source in virtual reality headsets is very low, however, and the exposure limits are not likely to be exceeded. Manufacturers give guidance on the maximum duration of use for these types of headsets. While the scientific evidence does not show any increased risk to the eyes, there may be other effects, like disrupting normal sleep and wake patterns, which might be particularly important for this age group.
As people age, they may experience more difficulties with blue light sources. Some LED lights that pulse, result in phantom images when someone turns their head or if the eye is moved quickly. These effects can be distracting, and in some cases, older eyes might perceive lights to be blurred, which might cause difficulties, for example when the lights are used on destination displays on the front of buses. Older people also tend to experience glare more often, while younger people seem to experience flicker more often than their elders.
3.4. Does exposure to light from LEDs in the evening disturb natural sleep patterns?
All light affects the circadian rhythm, which is the body's 24-hour internal clock that alternates between sleepiness and alertness at regular intervals and is also known as the sleep/wake cycle. Most people naturally dim or turn off the lights to sleep; darkness is a cue for the brain and body to rest.
The widespread use of LEDs is relatively recent. Therefore, only a small number of studies have looked at the effects of LEDs versus traditional light sources on circadian rhythms. It is important to note that LEDs do not fall into one hom*ogenous class; their influence on the circadian system depends on their specific properties.
There is some evidence that normal use of LEDs or screens illuminated by LEDs during the evening can affect the circadian system influencing sleep quality. However, the influence of different wavelengths of light on the circadian system is not completely clear yet. In addition, the activity being carried out on phones and tablets and computers also plays a role – watching an exciting movie or reading a thriller, for example, may hinder someone's ability to drift off to sleep.
3.5. Does optical radiation from LED lights affect the skin?
Some LEDs emit a narrow but concentrated band of light in the UV or ultraviolet range – UV LED. Although UV-LEDs are not widely used by the general public for their UV output, they are being used for their UV properties by the cosmetic industry, both by nail studios and for home use, which are increasingly opting to use UV LED gel lamps rather than UV gel discharge lamps because of their efficiency. Neither type of nail lamp appears to significantly increase the risk of non-melanoma skin cancer. However, there is insufficient data on the possibility of premature skin ageing and the risk to the eyes of professional operators. This topic is reviewed in the 2012 Opinion 'Health Effects of Artificial Light', produced by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR).
