Why too much blue light from your screens can be harmful


The blue light emitted from our screens can strain our eyes and make them dry. — 123rf.com

Blue light exposure has become a hot topic due to the amount of time that we spend in front of a digital screen every day.

Recent research indicates that adults spend an average of more than 12 hours a day in front of our smartphones, tablets, TVs and computers (and that doesn’t include usage during the MCO!).

Blue light is also known as high-energy visible (HEV) light as it is of a short wavelength that produces high amounts of energy.

HEV light can be found near the ultraviolet (UV) end of the light wavelengths that can be seen by human eyes.

Blue light surrounds us in our everyday life. It is naturally emitted by the sun and artificially emitted by digital screens.

The reason we see the sky as being blue is actually because of this type of light.

When these shortwaves from the sun strike against air molecules, it creates what our mind interprets as a blue sky.

Blue light is also responsible for regulating the circadian rhythms of our bodies, i.e. the sleep/wake cycles.

Negative effects

Because of our constant overexposure to blue light from our digital screens, it can have negative effects on our health, such as:

> Sleep cycle disruption

Due to its effect on our circadian rhythm, our sleep routine is at risk of being disrupted when we are overexposed to blue light at night.

Research conducted by Harvard University in the United States found that after more than six hours of exposure to blue light (compared to green light), blue light was responsible for shifting circadian cycles by twice as much as green light.

Blue light also suppressed twice the amount of melatonin than green light.

Melatonin is a hormone that regulates our sleep cycle.

Decreased levels of melatonin makes it difficult for us to fall asleep.

> Dry eyes and strain

One of the main effects of blue light is that it can cause eye strain and dry eyes after prolonged periods of exposure.

It potentially tires out the retinas when the eyes are exposed to it on a regular basis.

This is mainly due to the rapidly changing glare that forces the eyes to focus harder.

Symptoms can include a burning or stinging sensation, eye irritation, redness and sensitivity to light.

In addition, you may experience headaches, blurred vision, and neck and shoulder pain.

These are also the symptoms of another problem related to blue light: computer vision syndrome.

Also known as digital eye strain, this is a condition we have all probably encountered at some point or the other.

It is when your eyes are so fatigued, you need to rest them.

Fortunately, the symptoms of computer vision syndrome are mostly temporary, and will disappear if you space out the use of your devices and take regular breaks.

If the symptoms persist however, it may be a sign of more serious eyesight issues and a check-up with an eye specialist is highly recommended.

This might include a detailed examination that:

  • Assesses your work space situation, including lighting, distance from devices, time spent in front of screens and seat positioning.
  • Tests your visual acuity to determine if your near or distance vision has been affected before determining a diagnosis.
  • Identifies any vision problems that have gone untreated, such as astigmatism, farsightedness or nearsightedness.
Save your sight

Blue is one of the colours towards the UV end of the visible light spectrum, clearly represented by rainbows, which have increasingly shorter wavelengths with correspondingly higher energy. — ReutersBlue is one of the colours towards the UV end of the visible light spectrum, clearly represented by rainbows, which have increasingly shorter wavelengths with correspondingly higher energy. — Reuters

In this day and age, it is impossible to avoid digital screen time, whether it is working on our laptop, looking at our phone, watching TV or movies, and even checking our smart watches!

We love to stay connected, but the potential price to pay for that is a deterioration of our eyesight or a condition like computer vision syndrome.

One simple preventive method is to blink more often while using a screen.

Blinking helps to moisturise and refresh your eyes, thus helping to prevent dry eyes and strain.

Using artificial tears to lubricate your eyes, especially if you already have dry eyes, is also helpful.

Do note that you should apply them regularly, even when your eyes feel fine, in order to ensure that your symptoms don’t recur.

Another method is to follow the 20-20-20 rule, i.e. look at something 20 feet (6m) away for at least 20 seconds every 20 minutes.

You can set a repeating alarm on your smartphone to help you to remember to do this.

Cutting down on glare by adjusting the lighting around you and the brightness of your screen can help to reduce the strain on your eyes.

Glare and blue light can also be controlled, or even blocked, by using blue light screen filters or glasses that are designed to block HEV light.

Blue light glasses, which are specially-designed spectacles, do not require a prescription.

Good quality ones can block 100% of blue light on the lower spectrum, and up to 40% of blue light on the highest spectrum.

They are an increasingly popular way to protect one’s eyes against the artificial blue light and glare from all digital devices.

As there are no known side effects to wearing blue light glasses, it doesn’t hurt to try them and see if you find them helpful.

At the end of the day, cutting down on your screen time is still the best way to prevent digital eye strain and disruption of your circadian cycle.

While it may be unavoidable for work, do try to reduce the amount of leisure time you spend staring at a screen, whether it be surfing the internet, checking out your social media feeds or binge-watching the latest hot drama.

Datuk Dr Nor Ashikin Mokhtar is a consultant obstetrician and gynaecologist, and a functional medicine practitioner. For further information, email starhealth@thestar.com.my. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.

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