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Blue light: Harmful or Beneficial?

Updated: Oct 1, 2020

Blue Light Filter

Short wavelength, high-energy light called blue light is part of our visible spectrum that is naturally emitted by the sun. However, another source of blue light is technology including fluorescent lights, flat screen TVs, and computer and smartphone screens. This has been a very controversial topic especially in the recent years. Although, the largest source of blue light is the sun, these other sources are important to consider because of the amount of time spent using them, especially at a time like this when most people are working from home and using these devices possibly more than ever before.

Limited exposure to blue light can actually have some advantages; for example, it helps in regulating our body’s natural sleep and wake cycle, improves memory and mood and increases alertness. However, some early studies have shown that too much exposure to blue light from technology especially at night has some negative effects on our eyes and sleep cycle. There is inconclusive research suggesting that:

1) It can cause dry eyes by damaging the corneal epithelial cells and the stability of our tear film.

2) The lens in our eye can easily absorb this short wavelength light causing it to change color and lead to cataract formation.

3) Blue light can also damage cells in the central area of the retina, called the macula and lead to problems with vision.

Having said that, blue light cannot be entirely blamed for causing dry eyes and eyestrain when attributed to the use of electronics, it’s the amount of time we spend on these devices. Ultimately, to reduce dryness and eyestrain, taking breaks often (it’s recommended to look at something 20 feet away for at least 20 seconds after every 20 minutes on electronic devices), sitting far away from the screen (about 25 inches) and remembering to blink often and focus on complete blinks (believe it or not, a higher prevalence of incomplete blinks is noted with focused computer work) can all be helpful.

Increased exposure to blue light in the evenings can cause a decrease in the hormone called melatonin, which is produced by our brain and controls our sleep cycle. This decrease in melatonin can negatively impact the quality of sleep, which is so important for proper brain function. In addition, it can be argued that staying awake late at nights on our phones/laptops can disrupt sleep as well by reducing the amount of sleep we get at night.

In conclusion, there is a lot of ongoing research about the effects of blue light on our eyes and we are unsure if blue blocking lenses have significant protective qualities or not for protection from eye disease. We do know, however, that blue light before bed can effect your sleep cycle. So, if you must use screens, including TV, 1-2 hours before bed, invest in some blue blocking glass or consider using night mode on your device. Feel free to discuss more about blue light and blue light protection with one of our optometrists in more detail at your next visit!



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