How to help children guard against blue light? Support from Vision Kids!

Between LEDs and digital screens, our children are increasingly exposed to blue light. There is no shortage of concern about the possible effects on their health: both the retina and circadian rhythms could suffer. But how can they be defended? Screens and filtering lenses seem to do little, while boosting the intake of nutrients that make up the eye's natural defenses has proven to be a more promising strategy.

The use of LED lights has increased gradually from the 1990s to the present, abetted by a dutiful attention to the economic and ecological costs of ambient lighting. As a result, our exposure to blue light, of which LEDs are particularly rich, has increased. 

The proliferation of digital tools such as computers, tablets and smartphones has also made its contribution; in fact, the backlighting system of their screens involves precisely the use of LEDs.

Considering that, nowadays, we also spend more than 90 percent of our time indoors, often in front of such screens or exposed to artificial lighting, the question arose: does increased exposure to blue light have any effects on our eyes and health more generally?

In fact, the use of digital screens has been associated with undesirable effects on vision. For its part, blue light triggers reactions in most tissues of the eye, particularly the cornea, lens and retina. 

Depending on the type of blue light one is exposed to, temporary or permanent damage may occur, and although in the immediate term the consequences of exposure may be insignificant, experts in the field are concerned about the possible consequences in the long term, especially for children, who, it is likely, will spend a greater portion of their lives exposed to large amounts of blue light.

In addition, although of concern is the increase in exposure to blue light from artificial sources, it is good to remember that this light is found everywhere in our environment and also comes from the Sun, the Moon and flames. 

The intensity of this natural blue light varies throughout the day and is highest at midday and lowest at sunrise and sunset; it is also influenced by latitude, altitude, weather conditions, and season.

The human organism has evolved to take advantage of variations in the intensity of this component of light to regulate its circadian rhythms, that is, those functions that need to be synchronized with the flow of the hours of the day, such as the sleep-wake rhythm. It is, therefore, fair to wonder whether increased exposure to blue light may also affect these rhythms.

So let's try to understand the possible risks associated with increased exposure to blue light and how they can be abated, focusing primarily on the structure of the eye that seems most at risk: the retina.

What is the retina in the eye and how it works

The retina is a structure composed of as many as ten layers within which are cells capable of capturing and deciphering visible light (400-700 nm). 

In its innermost part are the nerve fibers of the optic nerve, through which signals picked up by the retina are transported to the brain and distributed to its different areas. 

The outermost part (the pigment epithelium), on the other hand, is critical for supplying the retina with the nutrients needed for the proper functioning of the two structures classically associated with vision: the cones and rods; it is also critical for its development, for counteracting the oxidative stress generated by exposure to light, and for several other processes important for the proper functioning of the eye.

Cones and rods capture light, but they are not the only retinal cells capable of doing so. Deeper down, in fact, there are also intrinsically photosensitive retinal ganglion cells (ipRGCs), within which melanopsin, a pigment that absorbs mainly precisely blue light, is concentrated.

Stimulation of hypRGCs by blue light plays an important role in a response to light that is not associated with image perception. Thus, blue light comes into play in both vision and other processes associated with light exposure. 

What is blue light and what are the effects on the eyes

But what, exactly, is blue light? It is the electromagnetic radiation with the highest energy among the wavelengths in the visible spectrum. In turn, it can be divided into two categories: blue-violet light (380-450 nm, also known as "high-energy violet") and blue-turquoise (450-500 nm). 

Most research has focused on blue-violet light, but blue-turquoise light can also reach the retina, reducing levels of melatonin (a substance important for sleep regulation) and thus affecting circadian rhythms. In addition, light stimulates the release of dopamine and serotonin, two neurotransmitters that also affect mood.

Regarding the effects of blue light on ocular structures, the shorter wavelengths can alter the surface of the eye by generating oxidative stress and inflammation and inducing cell death. 

In the retina, prolonged exposure to blue light increases reactive oxygen species, promotes deposit formation and microvascular changes-all associated with vision problems typical of aging. Photoreceptors diminish, lipids oxidize, and cells die.

In addition, blue light can also damage the lens of the eye, especially as it ages, causing it to gradually yellow and darken, posing a risk of cataracts.

Studies to date suggest that even brief exposures at doses considered safe can affect the functioning of cones and rods, and that blue light can trigger toxic phenomena even at intensities normally found in our homes.

Some research has focused on digital screens, noting chronic damage, for example, following exposure to those on phones for more than 8 hours a day for more than 5 years. The damage appears to involve all layers of the retina and appears to be cumulative and time-dependent.

In addition, more recent studies also suggest effects beyond vision, suggesting, for example, a role for blue light in the onset of migraine.

How to protect yourself from blue light

Today, the brightness of screens is 100 times lower than the dose considered potentially dangerous; however, of concern is the cumulative effect of this exposure over the long term.

Therefore, the first way to protect children from possible harm from exposure to blue light is to limit it, for example by avoiding the use of LED lights with a high blue light component in environments where they spend a lot of time. Better to prefer warmer lights rather than cooler lights, and reduce exposure to screens before bedtime and during the night to avoid disturbing their circadian rhythms.

The effectiveness of strategies such as the use of screens and filter lenses is uncertain: studies conducted have not found significant retinal benefits.

Instead, it may be helpful to increase the eye's natural protective systems, consisting of the pigments in the macula (lutein and zeaxanthin), which work synergistically with antioxidants such as vitamin C , vitamin E and zinc to limit the oxidative stress generated by blue light.

How to protect children from blue light with nutrition

Both lutein and zeaxanthin cannot be synthesized by the human body; therefore, they must be taken from outside.

These are carotenoids found in fruits and vegetables (especially green leafy ones) and can be taken with dietary supplements, which can be used to protect the supply of lutein and zeaxanthin that is abundant in children's eyes but tends to diminish as they age.

Lutein and zeaxanthin absorb blue light, prevent the formation of reactive oxygen species and help eliminate them. They also counteract inflammation that exacerbates light-induced damage and may prevent the proliferation of blood vessels typical of some eye diseases. 

Their benefits for retinal health are suggested by numerous studies, which have also considered intake through dietary supplements.

Vitamin C is present in several tissues of the eye, while vitamin E is particularly abundant in the membranes of retinal cells. Both prevent oxidative stress and protect cell membranes.

Finally, zinc also has recognized antioxidant properties and is particularly abundant in the eye; along with lutein, zeaxanthin, and vitamins C and E, it is considered a key nutrient in protecting the eye from blue light-induced damage.

The best way to protect children from the side effects of this component of light seems, therefore, to take advantage of the properties of nutrients that are abundant in our Mediterranean diet and can also be easily taken through well-formulated dietary supplements.

Bibliographic references:

Antemie RG, Samoilă OC, Clichici SV. Blue Light-Ocular and Systemic Damaging Effects: A Narrative Review. Int J Mol Sci. 2023 Mar 22;24(6):5998. doi: 10.3390/ijms24065998

Cougnard-Gregoire A, Merle BMJ, Aslam T, Seddon JM, Aknin I, Klaver CCW, Garhöfer G, Layana AG, Minnella AM, Silva R, Delcourt C. Blue Light Exposure: Ocular Hazards and Prevention-A Narrative Review. Ophthalmol Ther. 2023 Apr;12(2):755-788. doi: 10.1007/s40123-023-00675-3