How do smart phones damage your eyes?

23 July 2019

Author: Kate Green

How smart phones can damage eyes with blue light

The age of the smartphone


Smartphones have become a staple item in everyday life, with 80% of UK consumers owning one in 2018. This number is sure to continue rising as the years go by, and smartphones become more affordable and therefore more accessible. They’re useful for just about everything; checking train times, snapping a quick photo, getting involved in the family group chat, or even – as the mobile was first intended for – making a phone call. All of this has resulted in the average adult spending 8 hours and 41 minutes on digital devices each day. For some individuals, however, this number is likely to be far greater. Many jobs require people to be sat in front of computer screens for 35-40 hours a week, even without your own personal use of a smartphone outside of work hours. While this is great for staying connected with people, arranging transportation, and getting work completed quickly and efficiently, what is the impact on our health?


What is blue light?


As the 2010s have been dubbed “the decade of the smartphone”, it’s no surprise that extensive research has been conducted in this area. One finding which seems to be mentioned everywhere is “blue light”. This is the light which is emitted from our phones, tablets and laptops and, sadly, it has been found to have negative effects on our eye health. Studies suggest that it has “a potential to lead to macular degeneration”, bypassing the pupil and cornea to beam directly into the retina. The blue light is thought to affect your central vision as it kills off photoreceptor cells in the retina. Unlike some other cells in your body, once these cells die, they cannot regenerate. This means that any damage done to them is permanent.


Blue light also comes from sunlight, which we’re all aware is bad for our eyes. We even wear sunglasses to help shield our eyes from it – so should we be doing the same with our screens? Blue light is particularly toxic as it has a shorter wavelength than other colours of light, meaning it has more energy. Blue light also prevents your body from releasing melatonin, the chemical your body needs to feel sleepy. As blue light also comes from the sun, it tricks our brains into believing it’s still day time, making it more difficult to sleep. Using your screen when in dark surroundings can actually exacerbate its effects, leading Apple to introduce “night shift” featuring a more yellow-toned screen, and Samsung to offer a “blue light filter”.


What is age-related macular degeneration?


Excessive screen usage and exposure to blue light has been found to accelerate the development of age-related macular degeneration (AMD). AMD mostly occurs after the age of 60, but experts believe that, as time goes on and screen usage increases, this will be brought forwards. In fact, it’s predicted that by 2040, 288 million people will be affected. As we previously mentioned, blue light destroys the eye’s photoreceptor cells and therefore hinders central vision. Some newer studies, however, suggest that blue light instead “promotes the growth of poisonous molecules” in your eyes, causing AMD. This is because it is beamed directly into your retina, causing much more damage than other less intense forms of light.


Symptoms of AMD are usually seen in your central vision in the form of distorted or blurred objects. As the condition progresses, black spots may appear in your central vision, blocking your view. Other symptoms can be colours appearing faded, hallucinations, and straight lines appearing wavy.  AMD is one of the world’s leading causes of blindness, so it’s important to understand how your lifestyle choices – such as screen use – may affect its development.


What are the symptoms of computer vision syndrome?


Aside from AMD, a milder side effect of high screen use is a condition called Computer Vision Syndrome (CVS). There are multiple symptoms including:

  • Blurred vision
  • Headaches
  • Pain in shoulders and neck
  • Dry and red eyes
  • Difficulty in concentrating
  • Making errors


First and foremost, CVS tends to develop as a result of reduced blinking. When staring at screens, we tend to blink a lot less, causing our eyes to dry out and rid themselves of a protective layer of moisture. When we’re using screens, we also tend to focus and refocus our eyes repeatedly. Things move around on the screen, demanding more effort from our eyes, often leading to eye strain. CVS is said to occur after looking at screens for more than two hours a time but, if you consider how many people work in office- or computer-based jobs, it becomes clear how large a problem CVS is becoming.


How can you reduce the symptoms of CVS?


As this is such a large-scale issue, lots of research has been conducted in how to minimise the effects CVS has on your everyday life and overall health. In terms of comfort for your eyes, it’s recommended that you keep your screen a minimum of an arm’s distance away and increase the font size, to reduce eye strain. Eye experts also place importance on the “20-20-20 rule”. Every 20 minutes, look at an object 20 feet away, and focus your eyes on it for 20 seconds. This relieves your eyes from the brightness of your screen, and ensures that you keep them used to focusing on objects a further distance away than your computer monitor.


Some people liken CVS to repetitive motion injuries, as your eyes are likely just performing the same sequence of movements over and over again. To make things as comfortable as possible for yourself, it’s recommended that you turn down your screen brightness, and have your computer monitor at least 18 inches away from you, with the top of the screen positioned at eye level. This will reduce eye strain, and also improve your posture, helping with neck and back pains. You should also make an effort to blink more, minimising the impact of the dry eye that comes with CVS. Up to 90% of people who work with a computer screen show some CVS symptoms, so you’re not alone, but it’s important to know how you can reduce its effects on your overall health.


When is your risk greater?


People with pre-existing vision problems are at a greater risk of developing CVS. It is also likely to exacerbate conditions like dry and red eyes, made even worse if you work in low lighting. It goes without saying that the more time you spend looking at screens, the great your risk of developing issues is. Over 83% of people surveyed about their screen usage said they used digital devices for over 2 hours a day, and over half of respondents use more than one device at the same time.


In 2019, it’s become a normal part of life. We’re becoming more dependent on our phones, computers and tablets all the time. We need them for work, play, socialisation – just about every part of our daily lives involves some form of screen. Rather than limiting what we can and can’t do with them, it might be more realistic to look at how to mitigate the negative effects. Utilising different coloured tones on our digital screens, as we’re already seeing with Apple, could be the answer, and certain eyewear is already proven to help.


Ultimately, we don’t know the long-term effects of being exposed to screens for almost every waking minute of the day. We can, however, tackle the short term impacts. If you sit up a bit straighter, blink more often, and practice focusing your eyes on varied distances, you’re already doing more than most to preserve your sight in this digital age.

Back to Blog