Recently, leading optometrists in the United States have issued warnings in a new, more robust public awareness campaign about the danger that blue light can cause in children’s eyesight. They report that upwards of 100,000 adults and children will become legally blind because of blue light’s adverse effects.
Blue light is emitted by video display terminals, computer screens, notebooks, tablets, laptops, smart phones, and other electronic devices. Moreover, its damaging effects are cumulative.
But, what has research in the past revealed about the effects of blue light? While blue light provides the benefits of “boosting attention, reaction times, and mood,” Harvard Health Publications adds the following caveat: “Study after study has linked exposure to blue light at night [with increased risk of] several types of cancer (breast, prostate), diabetes, heart disease, and obesity.”
Exposure to blue light at night tends to suppress the body’s production of melatonin, which is the hormone that influences circadian rhythms. Harvard Health Publications, for instance, has published that lower melatonin levels is associated with certain types of cancer and cardiovascular problems. When performing clinical studies to see the effect of 6.5 hours of blue light exposure, Harvard researchers found that “the blue light suppressed melatonin for twice as long as green light and thereby shifted circadian rhythms by twice as much.”
The danger of blue light, however, does not end there. Blue light also adversely affects the health of eyes, especially those of children.
According to Houston optometrist, Dr. Sophia W. Barnes, “Children are vulnerable because they have large pupils and pristine lenses.” She then emphasized, “The American Academy of Pediatrics states that no child under the age of two years should be on any computer device. And I would extend the limitation to children five years of age.”
The American Academy of Pediatrics (AAP) documents that, on average, today’s children spend seven hours a day on entertainment media. The AAP has previously warned that “excessive media use can lead to attention problems, school difficulties, sleep and eating disorders, and obesity, [as well as] provide platforms for illicit and risky behaviors.” Now, the AAP adds the risk of permanent eyesight damage to the list of reasons why screen time must be limited.
The Professional Eye Care Associates of America (PECAA) categorizes blue light into “good” and “bad.” If blue light falls under the 465 – 500 nanometer (nm) range, then it is “good” – which constitutes the beneficial aspect, mentioned earlier, of blue light and how it boosts attention during daylight.
Meanwhile, “bad” blue light is of a shorter wavelength range, 320 – 460 nm. The scientific term for “bad” blue light is High-Energy Visible (HEV) light. HEV is of particular concern to many eye care professionals because this “is the radiation transmitted to the crystalline lens of the human eye.”
In ophthalmology, or the branch of medicine dealing with eye disease, blue light’s HEV wavelength range is identified as “the most harmful wavelength to the retina.” It has been implicated as a cause of macular degeneration.
Dr. Paul Karpecki, the Director of Education for PECAA, has even admonished: “Studies have shown that [“bad”] blue light frequencies (similar to what we are exposed to with LED cool blue or even tablets and smartphones) are 50 – 80 times more efficient in causing photoreceptor death than green light.”
The PECAA likewise reports that children should spend less time on computers, tablets, or playing video games not only to minimize sleep disorders in children, but also to protect the health of children’s eyes. Recall that blue light affects circadian rhythms, which in turn leads to sleep issues. But, what is more alarming is that children are more susceptible to blue light because they physiologically lack ocular lens pigments in their crystalline lens. Consequently, their eyes absorb more of these HEV rays and thereby lead to higher risk for damage in children’s retinas, some that manifest later in life.
Since blue light adversely affects health, eye care and medical professionals are wanting a widespread technological push to selectively filter blue light. Until then, screen time and media use by children must be limited as a preventative measure.