What Is Blue Light And How Does It Affect Your Eyes?
Although people associate blue light (or high energy visible light (HEV, wavelength 380 – 500 nm) with computers and phones, the largest source of blue light is the sun. Other sources include:
- fluorescent light,
- compact fluorescent lightbulbs, and
- LED light.
We spoke to Dr Dirk J. Booysen of Dirk Booysen & Associates Inc. to find out more about the influence of this kind of light to our eyes.
“Approximately one third of visible light is considered HEV or “blue light’. Exposure to ultra violet light (wavelength 100 – 380 nm) increases the risks of cataracts, growths on the eye, and cancer. Currently we know very little about the effects of blue light on the eye, and it may therefore be premature to take preventative measures against this kind of light. What we do know is that it scatters more than other visible light and penetrates the cornea readily to reach the retina. Due to this scattering, is not easily focused by the eye, leading to reduced contrast and digital eyestrain. The fact that this type of light easily penetrates all the way to the retina may increase the risks of macular degeneration,” Dr Booysen explains.
Blue Light and Light therapy – it’s actually good for you!
While preventative measures may be more harmful than the blue light itself. It is well documented that some exposure to this light is essential for the following functions:
- it contributes to good health,
- it boosts alertness,
- it helps memory and cognitive function, and
- it elevates mood.
Light therapy (containing blue light) is used to treat seasonal affective mood disorder (a type of depression associated with changes in seasons also known as S.A.D.) and blue light is also important in regulating circadian rhythm – the body’s natural wakefulness and sleep cycle. Exposure to blue light during daylight hours helps maintain a healthy circadian rhythm. Too much blue light late at night while reading on an iPad, e-reader or computer, can disrupt this cycle, potentially causing sleepless nights and daytime fatigue. Not enough exposure to sunlight (including blue light) in children could affect the growth and development of their vision and increase the risk of short-sightedness in teens and young adults.
So how can you maintain good eyesight?
The best way to protect your eyes against digital eyestrain from blue light in devices is to take regular breaks using the “20-20-20” rule. This is how it works: for every 20 minutes, shift your eyes to look at a distant object at least 20 feet (6 meters) away for at least 20 seconds.
However, if you are using your iPad, smartphone, or computer constantly, a convenient way to reduce blue light digital eyestrain is to use a blue light filter on your screen or in your spectacle lenses. It must be noted that more research is needed before it can be established whether these filters are truly effective. Therefore the consensus is that until scientific evidence proves that they are effective, filters for this type of light should not routinely be recommended for use with digital devices.
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Click here to find out more about this kind of light therapy.