Elizabeth Saenger, PhD
When you drive at night, and see the glare of streetlights, or read your email right before going to bed, you might have trouble going to sleep. That’s because the light you see tells your eyes that it is still day, and not the right time to secrete the sleep hormone melatonin.
Protective eyewear would help you keep the melanopsin in your retina from telling your inner clock that it was day. Melanopsin, a light-senitive protein in the eye not to be confused with the melatonin secreted in the brain, helps regulate your circadian rhythms. Protective eyewear screens out the blue light from the street lights, your laptop, and so on. Melanopsin can thus let your body react as if it were night. As a result, you would be able to get to sleep more easily at bedtime.
But would children or teens ever need protective eyewear? Surprisingly, the answer is that they are more vulnerable to artificial light than adults.
Children who are exposed to light at night are especially vulnerable to its unintended consequences. That is because children have bigger pupils, and clearer lenses, than adults. As a result, their eyes literally take in more of the light that is present. For example, a ten-year old will take in twice as much light as an adult of 45, and ten times as much as an adult of 90.
Not only do children absorb more light, but their reactions are more long-lasting. A 2018 study found that preschoolers exposed to bright light an hour before bedtime decreased their production of melatonin by almost 90%. Even when the light was dimmed again, most children did not secrete even 50% of their baseline level of melatonin. Bedtime for Children explains more.
This means that to get the best sleep, children should be shielded from bright light at least an hour, and many experts say two to three hours, before bedtime. If the environment cannot be controlled, protective eyewear can be the answer.
Teens can also benefit from protective eyewear given features of their life-style. This is obviously true for hanging out with friends at brightly-lit malls on Saturday night. Yet protective eyewear can shield teen eyes from lower levels of light at night at home well.
The right kind of amber glasses can be uniquely helpful for teens because teens undergo several changes in adolescence which can interfere with their sleep.
For example, teens have increased sensitivity to evening light, which encourages them to stay awake. They also secrete much less melatonin, and it enters the bloodstream later in the evening, prompting later bedtimes. (For other changes in adolescence that affect circadian rhythms, see How to Understand the Teenager in Your Life.)
In addition, surprising as it may seem, teenagers need more sleep than children.
The overall effect of these biological changes, and needs, mean that teens are at risk for getting insufficient sleep. Insufficient sleep means they may not do as well on tests, are more likely to suffer “drowsy driving,” and so on. The occurrence, and severity, of these problems can be reduced with protective eyewear.
Thus, although technology often disturbs the circadian rhythms that have governed mankind for centuries, it has also provided a scientific solution for correcting the problem.