The disruptive effects of artificial light on sleep are well documented, and have received an increasing amount of attention in recent years—with good reason. Nighttime exposure to artificial light—which for the great majority of us happens without much thought or awareness—disrupts the body’s circadian rhythm, altering the 24-hour biological clock that controls our sleep-wake cycle. In addition to wreaking havoc with sleep, disruptions to circadian rhythms also have been associated with a number of serious diseases, including cancer, diabetes, depression and heart disease.
In particular, research in recent years has shown that blue wavelength light is especially harmful to circadian rhythm function. Studies have shown that blue wavelength light has uniquely harmful effects on humans, and suppress melatonin levels more vigorously than other light wavelengths. Unfortunately, many energy-efficient light sources produce high concentrations of blue light. Blue light is emitted by electronic devices, energy-efficient light bulbs, and other common light sources.
Research investigating blue-light blocking—most often in the form of goggles that filter out this particular wavelength of light—has shown promise. A new study of cataract patients indicates that artificial lens implants can help improve sleep. Scientists at China’s Sichuan University studied the effects of blue-light blocking artificial lenses implanted during cataract surgery. The study involved 40 patients who required surgery for cataracts in both eyes. Cataract surgery commonly involves removal of the eye’s damaged lens, and insertion of an artificial lens. Cataracts are a common condition among older adults—approximately 60% of people over the age of 60 experience cataracts. The study subjects—26 women and 14 men, with an average age of 74—were given artificial lenses with blue-light blocking capability. Researchers assessed patients sleep quality before surgery and again two months after surgery. They found patients’ sleep had improved significantly across several measures:
Lens replacement surgery is necessary for cataract patients. But there are other, less invasive ways to filter out blue-light that are also being investigated by sleep scientists. Research has shown the benefits to sleep of manipulating and controlling exposure to blue light:
This area of research is critically important, and I expect we will see a great deal more investigation into the effects of blue wavelength light on sleep and health. But you don’t need special goggles or eye lens implants to protect your circadian rhythms and your sleep from the negative effects of artificial light. Here are some low-tech suggestions that can help you:
Being aware of the effects of nighttime exposure to light and making some basic changes to bedtime routines can go a long way toward getting you the darkness you need to sleep well, even in this ever-bright modern age.
Michael J. Breus, PhD
The Sleep Doctor™