Over the last 50 years, there has been an exponential increase in the number of digital devices owned by households and used by people in their everyday lives. In a survey report by the United States Department of Commerce Economics and Statistics Administration, their results showed that over a period of just 30 years, the percentage of American households with a computer have increased by more than ten-fold . Specifically, in 2016 their survey reported that 89% of American households owned a computer, increasing from just 8% in 1984.
The impact of computer use on eye health
Prolonged use of digital devices such as computers is known to result in an eye condition called digital eye strain (DES), also known as computer vision syndrome (CVS). DES is a collection of symptoms that result from prolonged digital screen exposure or improper device use. These symptoms include red eyes, eye discomfort and pain, headaches, and dry eyes. Its effects are usually temporary and will resolve themselves once you have taken your eyes away from the digital device screen for an hour or two. But DES and its symptoms can be debilitating and lead to a decrease in visual performance, to the point that it hinders your productivity and efficiency as a worker or student.
A study by Clayton Blehm et al. found that 20 percent of computer users experienced transient myopia at the end of their working day . Myopia (near-sightedness) is a visual impairment where you can see near objects clearly but far away objects appear blurry. Transient means that the symptoms are not permanent.
It is recommended that if you must engage in digital device use for long periods of time, you can lessen your ocular symptoms by using the 20-20-20 rule . A rule where you take a break every 20 minutes, to look at something 20 feet away (about 6 metres) for at least 20 seconds. This technique ensures that your focal muscles around the lens in your eye do not become strained from the fixed viewing position that often comes with using a computer for a long period of time continuously.
How does your workstation setup affect DES symptoms?
There are several factors of your workstation that may cause DES symptoms, which include the following:
Glare from the computer screen or surroundings
Glare occurs when the light of your surroundings is too intense for your eyes to adapt, resulting in the loss of visual performance and sometimes discomfort. While your iris (the coloured part of your eye) naturally mediates the amount of light entering the eye through the pupil (the black part of your eye), the muscles can become strained if forced into an excessively bright lit environment. Glare can come from any light source. To minimise glare while you are working, you should ensure that the lighting of your workstation is appropriate. It should be bright enough that you can see well without straining your eyes, but it shouldn’t be so bright that it creates ocular discomfort. Ideally, the brightness of your digital screen should roughly be equal to the brightness of your surroundings.
Placement angle of your computer
With computers coming in a wide variety of styles and sizes, the angle of the screen within your workstation setup is a vital consideration that may affect your visual performance. The angle of your fixed viewing position when you are looking at a screen can drastically increase symptoms of dry eye disease (DED). If your computer is positioned higher than your eye level, the front surface of your eye is more exposed than normal and this can dry out your eye . The abnormal increase in the exposed surface area of the front surface of the eye (also called the cornea) means that when you blink, there is not enough tear film to adequately lubricate the cornea. This is because your eye is used to producing enough tear film to lubricate the cornea when it is not overexposed. Making sure that your computer is placed level or slightly lower (15-20 degrees lower) than your eye level will help decrease the chances of developing DED symptoms.
Font size of text
Yuliya Bababekova et al. noted in their publication on the Optometry and Vision Science Journal  that the font size of text on your digital screens should be 3 times bigger than the minimum font size that your eyes can see. This ensures a more comfortable reading experience and better sustained visual acuity. Visual acuity refers to the clarity and capabilities of your vision. While not directly connected to the physical distance of your computer, having a large enough text size minimises the strain placed on your eyes, which may decrease the risk of developing visual symptoms.
Distance between the eyes and the screen
The distance at which you are viewing material on your computer can contribute to premature visual fatigue and DES. It is advised that computer screens be placed at a distance of at least 60cm from the eyes to avoid excessive strain on the eyes.
All in all, when positioning your computer, consider where you will be straining your eyes the least, without exacerbating any musculoskeletal symptoms from poor posture. For more information on how best to protect your eyes, it is advised to consult with your eye care professional.
 Camille Ryan. Computer and Internet Use in the United States: 2016. American Community Survey Reports. United States Census Bureau, U.S. Department of Commerce Economics and Statistics Administration. 2016.
 Clayton Blehm MD, Seema Vishnu MD, FRCS, Ashbala Khattak MD, Shrabanee Mitra MD, Richard W Yee MD. Computer Vision Syndrome: A Review. Survey of Ophthalmology. 2005.
 Kiersten Boyd. Computers, Digital Devices and Eye Strain. American Academy of Ophthalmology. 2020.
 Sukanya Jaiswal BOptom, Lisa Asper PhD OD, Jennifer Long MSafetySc PhD FAAO, Abigail Lee BOptom, Kirsten Harrison BOptom, Blanka Golebiowski BOptom PhD. Ocular and visual discomfort associated with smartphones, tablets and computers: what we do and do not know. Clinical and Experimental Optometry, Volume 102, Issue 5, page 463-477. 2019.
 Yuliya Bababekova, Mark Rosenfield, Jennifer E. Hue, Rae R. Huang. Font Size and Viewing Distance of Handheld Smart Phones. Optometry and Vision Science: Volume 88, Issue 7, page 795-797. 2011.