Blue light and our eyes
In much the same way as smoking or a sedentary lifestyle has become a concern for primary care physicians, blue or high energy visible (HEV) light has become a concern for eye care providers. More recently, HEV light has become the new UV light. Although we have yet to fully understand the magnitude and impact or HEV on ocular health, we certainly know that it is everywhere. HEV light is high frequency radiation in the violet-blue emission range from 400 nm - 500 nm. Most common and recognizable sources of HEV blue light are from the sunlight, compact fluorescent lamps (CFL), and light-emitting diode (LED) screens like computers, tablets and cell phones.
In terms of our ocular health, UV light affects the anterior part of our eyes causing skin cancers of the eyelid, pinguecula, pterygium, photokeratitis (i.e., sun burn of the cornea), and dermatochalasis (i.e., droopy eyelids). It also contributes to cataract formation. Blue or HEV light on the other hand, penetrates deeper into the retina causing photo-oxidative changes. Over time, this cumulative oxidative stress can contribute to age-related macular degeneration, the leading cause of blindness in people older than 55 years old.
The most prevalent source of UV and blue light is the sun. But did you know that the most common indoor sources of blue light exposure comes from CFLs and LEDs? The CFLs are those "screw-in" fluorescent bulbs that have essentially replaced incandescent light bulbs. LEDs are found in virtually every single electronic device that has a screen, such as computers, smartphones and tablets. Unfortunately, studies have shown that these same everyday electronic devices emit the highest levels of HEV blue light. And although the exposure to HEV light is not new, the amount of exposure time each day has drastically increased in recent years.
According to some studies, kids 8 to 18 years old are spending 7.5 hours per day viewing LED backlit screens. Kids also tend to have larger pupils, allowing more of the HEV blue light to penetrate into their eyes. Furthermore, kids under the age of 18 years old are at even greater risk because their crystalline lenses have not fully developed sufficient ocular lens pigment (OLP) and melanin, allowing blue light to enter at full strength.
Besides the risk to the retina, excessive HEV blue light exposure can also cause eye strain and fatigue at the end of the day. It has been postulated that blue light is "myopically" defocused in front of the retina, thereby causing eye strain and fatigue for those using these electronic devices for numerous hours a day. By filtering out these harmful blue light, the eyes feel more relaxed.
So far, we have learned that HEV blue light can lead to long-term retinal damage and eye strain. A more surprising finding about constant blue light exposure is how it can affect a person's ability to fall asleep. According to a recent Harvard Health Publication, exposure to blue light after dark affects our circadian rhythm (i.e., our internal clock). While light of any kind can suppress the release of serotonin ("sleep" hormone), blue light does so more powerfully.
Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours). Consequently, this lack of sleep can lead to loss of focus and concentration, irritability and hyperactivity, especially in kids. In adults, this sleep disturbance has been shown to lead to chronic conditions such as diabetes, obesity, heart disease, depression, stroke and cancer.
Now that we know the negative effects of HEV blue light, what do we do about it? Since the use of CFLs in light bulbs and LEDs in electronic devices are not going away anytime soon, we need a way to filter and block out this harmful light. Fortunately, treatments that offer protection against UV and HEV light have recently proliferated. These treatments include special anti-reflective treatments (ARTs) and specialty lenses infused with ocular lens pigment and melanin. In our practice, we offer a variety of these treatments and would be more than happy to discuss which one is best suited for you. To schedule an appointment and learn more about the dark side of blue light, click here.
In terms of our ocular health, UV light affects the anterior part of our eyes causing skin cancers of the eyelid, pinguecula, pterygium, photokeratitis (i.e., sun burn of the cornea), and dermatochalasis (i.e., droopy eyelids). It also contributes to cataract formation. Blue or HEV light on the other hand, penetrates deeper into the retina causing photo-oxidative changes. Over time, this cumulative oxidative stress can contribute to age-related macular degeneration, the leading cause of blindness in people older than 55 years old.
The most prevalent source of UV and blue light is the sun. But did you know that the most common indoor sources of blue light exposure comes from CFLs and LEDs? The CFLs are those "screw-in" fluorescent bulbs that have essentially replaced incandescent light bulbs. LEDs are found in virtually every single electronic device that has a screen, such as computers, smartphones and tablets. Unfortunately, studies have shown that these same everyday electronic devices emit the highest levels of HEV blue light. And although the exposure to HEV light is not new, the amount of exposure time each day has drastically increased in recent years.
According to some studies, kids 8 to 18 years old are spending 7.5 hours per day viewing LED backlit screens. Kids also tend to have larger pupils, allowing more of the HEV blue light to penetrate into their eyes. Furthermore, kids under the age of 18 years old are at even greater risk because their crystalline lenses have not fully developed sufficient ocular lens pigment (OLP) and melanin, allowing blue light to enter at full strength.
Besides the risk to the retina, excessive HEV blue light exposure can also cause eye strain and fatigue at the end of the day. It has been postulated that blue light is "myopically" defocused in front of the retina, thereby causing eye strain and fatigue for those using these electronic devices for numerous hours a day. By filtering out these harmful blue light, the eyes feel more relaxed.
So far, we have learned that HEV blue light can lead to long-term retinal damage and eye strain. A more surprising finding about constant blue light exposure is how it can affect a person's ability to fall asleep. According to a recent Harvard Health Publication, exposure to blue light after dark affects our circadian rhythm (i.e., our internal clock). While light of any kind can suppress the release of serotonin ("sleep" hormone), blue light does so more powerfully.
Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours). Consequently, this lack of sleep can lead to loss of focus and concentration, irritability and hyperactivity, especially in kids. In adults, this sleep disturbance has been shown to lead to chronic conditions such as diabetes, obesity, heart disease, depression, stroke and cancer.
Now that we know the negative effects of HEV blue light, what do we do about it? Since the use of CFLs in light bulbs and LEDs in electronic devices are not going away anytime soon, we need a way to filter and block out this harmful light. Fortunately, treatments that offer protection against UV and HEV light have recently proliferated. These treatments include special anti-reflective treatments (ARTs) and specialty lenses infused with ocular lens pigment and melanin. In our practice, we offer a variety of these treatments and would be more than happy to discuss which one is best suited for you. To schedule an appointment and learn more about the dark side of blue light, click here.