Recently, the number of mobile phone users has proliferated greatly, with the ‘phone’ becoming a staple item for many across the world. With the growth of technology and the increasing integration of technology into our everyday lives, we have spent more time looking at mobile devices. Despite the utility of using such technology, staring at their screens for too long can have repercussions on our health.
Blue light
Blue light is a high energy range of visible light with a wavelength range of 380 to 500 nm. We are exposed greatly to blue light due to the widespread use of light-emitting diode (LED) technology in screens. Therefore, the usage of mobile devices, such as phones, tablets and laptops are all conducive to increased exposure to blue light.
Blue light is necessary for good health: it can energize the body, enhance mood and improve cognitive awareness. It also regulates circadian rhythm - this is the natural process that regulates the sleep-wake cycle. Exposure to blue light during the day can maintain a healthy circadian rhythm, keeping the body awake and reducing daytime tiredness.
However, blue light has several negative implications if one is exposed to too much of it. Sunlight is a major source of blue light - during the night, we are exposed to less blue light, detected by light sensors in the eyes and skin. This prompts the body to release melatonin, a sleep-inducing hormone that prepares us for sleep and rest. When one is exposed to blue light in the evening, through screens, our body releases less melatonin, disrupting their sleep cycle and leaving them tired throughout the day.
However, blue light can also cause macular degeneration, as it can beam through the cornea and lens into the retina and damage its photoreceptor cells. As photoreceptor cells do not have the ability to regenerate, they are damaged permanently and thus result in irreversible vision loss.
How to limit blue light exposure
Use the 20/20/20 strategy- When viewing a screen on a device, try to follow the 20/20/20 rule. Every 20 minutes, focus on objects that are approximately 20 feet away. Focus on these objects for 20 seconds before using the device again.
Keep your eyes moist- Install room humidifiers or buy eye drops to prevent your eyes from becoming dry and irritated when viewing screens. Blinking more can also reduce dry eye, replenishing the layer of protective moisture in your eye.
Minimize the blue light on your screen- Turn on the night shift setting on your phone or computer to shift its display to the warmer end of the colour spectrum. This prevents blue light from affecting your circadian rhythm and disrupting your sleep schedule. Blue light filtering screens can also minimize blue light exposure- research from PubMed Central shows that they can block the glare of 30-60% of blue light when slipped over a screen.
Computer vision syndrome
Another side effect of high screen use is Computer Vision Syndrome (CVS), a condition which can result in blurred vision, headaches, pain in the shoulders and neck, dry and red eyes, difficulty in concentrating or staying on task, and making errors such as typos. CVS arises due to reduced blinking as a result of viewing screens. Reduced blinking can cause the eyes to dry and lose moisture, making the eye surface more sensitive and prone to irritation. In addition, viewing screens requires us to focus and refocus on different things on the screen, overworking our eyes and potentially causing eye strain. The positions and angles at which we view screens, as well as the environment in which we are viewing devices can put the visual system under significant stress. People who stare at their screens for two or more hours are at the most risk of CVS.
How to prevent CVS
Location of the computer screen: It is more comfortable for the eyes when the one is looking downward. The screen should be about 4 or 5 inches below eye level. However, positioning the screen too low can result in neck problems. The screen should also be around 20 to 28 inches from the eyes. This is because staring too closely at a screen overexerts the ciliary muscle, potentially causing eye strain. Focusing up-close can also reduce blinking and irritate the eyes.
Lighting: Reducing the glare of blue light from screens can reduce the stress placed on the eyes. Anti-glare screens can be implemented to minimize the intensity of light reflected from the screen. Brightness should also be reduced in order to reduce the tension and strain on optic muscles.
Posture: Sit straight and don't view phones at an angle- this can injure your neck and back.
Increase font size: Make the content on your screen easier to read, to reduce eye strain. The optimum font size for viewing is around three times larger than that of the smallest font you can read.
Use the 20/20/20 strategy.
In conclusion, as screens and mobile devices are becoming exceedingly important, we must be more aware of the negative implications that the viewing of such screens can give rise to. Taking breaks, optimizing posture, adjusting viewing distance, improving lighting and blinking more are all steps that you can take to preserve your valuable eyesight in the current digital age.
Sources:
Writer: Isaac Chow
Editor: Shen Tan
Artist: Holly Liu
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