Your eyes face many dangers every day. Wind and artificially heated hair can dry out the eyes, dust, pollen, and windborne particles can damage the cornea, and exposure to even a small amount of ultraviolet light has been shown to increase the risk of developing cataracts, the most common cause of blindness worldwide for adults over the age of 40. However few are aware that seemingly innocuous blue light, with which we come into contact every day, could also be a potential cause of concern.
Research in the 1980’s showed that exposure to certain wavelengths of light can increase the secretion of melatonin, a hormone produced by the pineal gland that is thought to help regulate sleep and wake cycles. This discovery has led to a number of clinical benefits, and today light therapy is routinely used to treat a number of issues ranging from depression to eating disorders to age-related dementia. In fact, exposure to high energy, short-wavelength blue light is believed to boost alertness, help memory and cognitive function, and even elevate mood. However, this can be a double edged sword. The body functions optimally within certain specific cycles, called circadian rhythms, and these circadian rhythms are strongly affected by changes in light exposure. For example, we know that melatonin is naturally present at low levels during the day, begins being released a few hours before bedtime, and peaks in the middle of the night. Exposure to any light before bedtime, particularly the more powerful wavelengths at the blue-violet end of the spectrum, can cause a circadian delay, suppressing melatonin production and resetting the body’s internal clock to a later schedule. In studies, this resulted in participants taking longer to fall asleep, experiencing less REM sleep over the night, and taking longer to wake up in the morning. While the underlying reasons are still unclear, multiple clinical studies have found a link between the disruption of the body’s natural circadian rhythms and several diseases, including types of cancer (breast, prostate), diabetes, heart disease, and obesity.
In addition to disrupting the body’s natural sleep cycle, blue light could also be potentially damaging to the eyes themselves. While the lens of the eye ordinarily filters out the most damaging ultraviolet wavelengths, it does not block the visible violet and blue wavelengths that are only slightly less intense. Some believe that this intense light can, over time, have a damaging effect on the light sensitive cells that make up the retina. Several studies have concluded that blue light, more than other wavelengths of light, may increase the long-term risk of age-related macular degeneration, a common disease that affects central vision and is the leading cause of severe vision loss among people over the age of sixty. The jury is still out, and some believe that there is not yet enough evidence to show a definitive causal link between blue light exposure and retinal damage, specifically macular degeneration. However, we believe that protecting your eyes from over-exposure to particularly intense light sources of any kind is one of the best ways to keep your vision strong and sharp.
All of this is particularly relevant given the increasing popularity of electronic devices. Short wavelength blue light appears comparatively brighter to human eyes, making this among the most energy-efficient colors of light to produce. Compact fluorescent lamps and advanced, energy-efficient lightbulbs are more efficient primarily because they produce a greater percentage of blue light than is normal. Moreover, many of today’s electronic devices, like cell phones, tablets, and flat-screen televisions, use LED back-light technology to help enhance screen brightness and clarity, and these LEDs emit very strong blue light waves. Many think that this may be one of the reasons for the steady increase in complaints of eye fatigue and computer vision syndrome among office workers. Because blue lights are energy efficient and cost effective, we are all being exposed to more sources of blue light for longer periods of time.
In order to avoid some of these potential concerns, it can be advisable to dim the brightness of devices or make use of programs that filter out short-wavelength light in the evening, but the best and least popular answer is still to simply avoid your devices before going to sleep. Giving your eyes some extra time to rest and recuperate, particularly when they are exposed to intense light sources, can benefit long term eye health. If you have other questions about the health of your eyes, or would like to schedule a comprehensive eye exam, please contact Georgia Eye Physicians and Surgeons to make an appointment with Dr. William Segal or Dr. Marc Lay. Be sure to follow us on Facebook, Twitter, and Google+ for more information on how to keep your vision clear.