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Blue Light Research Update

Posted by Amanda Dexter on Feb 18, 2016 12:00:00 AM


We are all very aware that light is made up of electromagnetic particles that travel in waves. These waves emit different amounts of energy depending on the length of the wave. Shorter wavelengths emit higher amounts of energy, while longer wavelengths emit less energy.

Each wavelength is represented by a different color and is grouped into a certain category based on its range of wavelengths. These categories include gamma rays, x-rays, ultraviolet (UV) rays, visible light, infrared light, and radio waves. All of these groups combined make up the electromagnetic spectrum. 

The human eyes are only sensitive to a range of wavelengths in the electromagnetic spectrum  known as visible light. Visible light is made up of several different colors; violet, indigo, blue, green, yellow, orange, and red. The blue end of the spectrum is made up of shorter wavelengths, and therefore produces a higher amount of energy, as compared to the longer wavelength (red) end of the spectrum. 

Several studies have shown that exposure to the blue end of the visible light spectrum can interfere with sleep patterns. Some research also notes that long-term exposure can be damaging to eye health. Because of this, the topic of “blue light” has become very popular in the general public; therefore, you are likely to have several patients ask about blue light and how to prevent its harmful effects. 

Where Does Blue Light Come From?

Blue light represents a range of light from about 380 to 500nm in the visible light spectrum. Most people associate the presence of blue light with electronic devices with digital screens, such as TVs, computers, laptops, smart phones, tablets, etc. However, blue light also comes from fluorescent and LED lighting, as well as the sun. 

In its natural form, blue light does have some beneficial effects. Blue light from the sun helps to regulate your natural sleep and wake cycles, boosts alertness, helps heighten reaction times, memory, and cognitive function, it elevates moods, and has also been shown to increase the general feeling of well-being. 

Although blue light does have some known benefits, chronic exposure to higher amounts of blue light from our changing environments and increased exposure to electronic screens can have potentially serious harmful effects, such as sleep disruption, eyestrain and fatigue, and damage to ocular structures. 

What Effects Does Blue Light Have on Sleep?

In the modern age of technology, it is not uncommon for the someone to come home after a long day of work (usually on the computer) and wind-down by watching television, reading an e-book, or using their tablet or smart phone to update on social media. These habits allow the average person to be exposed to a high concentration of blue light throughout the day. Studies have shown that this particular spectrum of light causes a reaction that sends a signal to an area of the brain that is responsible for the production of melatonin, and ultimately tells it to stop producing this substance. 

As we all know, melatonin is responsible for sleep timing and circadian rhythms. At night, our levels of melatonin are supposed to rise in anticipation of sleep. However, exposure to blue light will suppress this normal production of melatonin and shift sleep cycles, lengthening the time is takes for someone to fall asleep at night, and taking more time for a person to wake in the morning. Additionally, research has shown that blue light not only decreases the production of melatonin, but also reduces the total number or REM sleep minutes during the night (remember that REM sleep is considered the most restorative form of sleep). 

Changes in sleep patterns and circadian rhythms can also have serious health implications. Our circadian rhythm also controls individual clocks that dictate the function of our body’s organs. When this natural rhythm is disrupted, people are at higher risk of all sorts of things such as heart attacks, obesity, type-2 diabetes, and various cancers. Difficulty sleeping has also been linked to mood problems, depression and anxiety, and increased risk of accidents. 

Can Blue Light Damage the Eyes?

Some scientists believe that chronic exposure to blue light can lead to early cataracts and age-related macular degeneration; however, the results have been inconclusive. What we do know is that we are seeing a much greater number of patients with macular degeneration and earlier cataracts, so the risk factors are clearly changing, but researchers have been unable to directly correlate this with an increase in exposure levels of blue light. 

How Can I Minimize the Effects of Blue Light?

Many of us use blue light emitting devices for several hours during a typical day of work, and then are exposed to more blue light as we wind-down from our work day. Most of us simply cannot turn off all of our digital devices, but there are several things that we can do to try and minimize our exposure. 

  • Dim the brightness of your devices as much as possible. This can easily be done by adjusting the levels on all of your monitors and screens. 
  • Download programs that filter out short-wavelength light. The newest apple update for the iPhone will have this as a new feature. 
  • Reversing the print on your e-readers so that the page is dark and the text is light may help cut down on blue light emission. 
  • Avoid devices as much as possible before going to bed! The worst thing that you can do is lay in bed and look at Facebook before trying to fall asleep!
  • There are several new types of lenses that selectively filter out blue light that can be used for people who spend several hours per day viewing monitors. 

-Dr. Dexter 

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Topics: Blue Light



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