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Computer vision syndrome (CVS) is caused by using digital displays — including computer monitors, laptops, tablets, e-readers, and smartphones — for too long without a break, without blinking enough, at an improper distance, or before sleep.
Symptoms include dry eyes and headaches, along with other kinds of strain that lead to overall fatigue.
While you can make the recommended lifestyle and environmental changes recommended for CVS without a diagnosis, an optometrist or ophthalmologist will be able to tell you if CVS is impacting your vision, making a refraction error worse (like temporary myopia), and what else you can do about it, like using special blue light-filtering glasses or attending visual therapy sessions to protect your eyes.
What Is Computer Vision Syndrome?
Computer vision syndrome (CVS) has an ominous ring because it is a serious type of repetitive strain injury that affects your vision, along with other aspects of your physical health. The condition is also called digital eye strain.
The average American worker spends seven hours a day in front of a screen of some kind — at work, during transit, and at home. Much of this screen time is white-collar labor, but increasingly, communication with loved ones and hobbies like gaming involve using a digital screen too.
CVS is characterized by:
- Eye, head, and neck discomfort
- Use of computers, tablets, smartphones, or e-readers that emit specific frequencies of blue light
- Using the eyes in specific patterns, like reading left to right repeatedly
- Trying to focus on bright objects that may be too small or too far away, like text on a small screen
Why Are Digital Screens Harder on the Eyes?
Using digital screens puts a particular type of strain on the eyes that reading and writing tasks without computers do not. With digital screens becoming increasingly important parts of our lives, it is equally important to know how to reduce the impact this kind of strain has on your vision.
Reading words on a computer screen is a different experience than reading printed words on a page.
Digital screens emit blue light, which is brighter and more intense than the yellow spectrum of light associated with daylight or some types of lightbulbs. Letters on a computer screen are not as defined as those on a printed page, and the contrast may be reduced. For example, a website may have a gray tinted background with darker gray letters, which could lead to eye strain.
Glare on the screen from bright lights or reflections on the screen may make it harder to stare at the screen when you need to look at the text or images for a longer period of time.
The distance between your eyes and your computer may contribute to an increased risk of computer vision syndrome. While you can safely hold a newspaper, magazine, or notebook closer to your face to see what you’re doing, the viewing range that is safe and effective for a computer screen is different. Your chair or desk may be at the wrong height for you, which contributes to difficulty seeing.
The setup at a computer or when you use a tablet or phone can also add to other types of physical strain like neck or shoulder tension. This increases muscle tension elsewhere, including around your eyes. The back-and-forth motion of your eyes across a screen can be very repetitive, leading to specific muscle strain.
If you do not get regular vision exams to manage existing eye problems, or you have an undiagnosed eye condition affecting your vision, struggling to read words on a computer screen can make eye strain worse.
Symptoms of Computer Vision Syndrome
If you spend two or more consecutive hours in front of a computer per day, you may develop computer vision syndrome (CVS).
Common symptoms of computer vision syndrome include the following:
- Eye strain
- Blurry vision
- Dry eyes
- Eye fatigue
- Neck and shoulder pain related to head and eye tension
Some people may experience dizziness, motion sickness, or tiredness after working with a digital screen for too long.
What Causes CVS?
There are several potential causes of these symptoms, including:
- Poor lighting in the room.
- Glare from the digital screen.
- Improper viewing distance, either too close or too far away.
- Poor seated posture.
- Uncorrected vision problems.
- Blinking less than normal.
Often, CVS results from a combination of these issues. Your seat may cause you to tilt forward, you may be sitting in too dark a room, and a refractive error like nearsightedness may be getting worse, for example.
Many people who stare intently at what they are working on do not blink enough, and this appears to be a very common cause of dry eye and eye strain among those using bright digital displays. The average healthy eye should blink 15 times per minute, but people who use computers or laptops are likely to blink a third as often while they are working.
Reading, writing, or performing close activities like sewing can also cause eye strain, but computer vision syndrome is unique in both causes and daily impact. With smaller, portable screens being used more often, you may add additional strain to your eyes, neck, head, and shoulders by viewing tablets or phones at uncomfortable angles.
How Is Computer Vision Syndrome Diagnosed?
To determine if you suffer from CVS, your optometrist will conduct a few tests.
- Patient history assessment: This will help your eye doctor understand your current level of screen use, your experience of vision problems, and any underlying health issues you may have.
- Visual acuity measurements: This includes the Snellen chart and other types of tests to determine your overall eye health and what might contribute to your eye strain.
- Refraction tests: These help your eye doctor determine your prescription, which can help them make recommendations about computer and other screen use to reduce the impact on your visual acuity.
- Eye focus tests: These are used to see how well your eyes focus on objects near and far, and to determine how the eyes move together.
Risks From Untreated CVS
Most symptoms associated with CVS are temporary, and they go away a few hours after you stop using the digital screen. If problems leading to consistent eye strain are not resolved, repeated experience of these issues can lead to reduced visual acuity after stopping work on the screen, and this may get worse.
A study found that most people who used flat screens as video display units (VDUs) reported eye symptoms of some type, which could lead to eye strain, including CVS. Of the 116 participants, 72 percent reported eye symptoms after using flat screens for an extended period; 23 percent reported moderate to severe symptoms, indicating that eye strain lasted after using the screens and impacted their life.
Symptom frequency included:
- 14 percent reported tired eyes.
- 12 percent reported sensitivity to bright light.
- 10 percent reported blurry vision in the distance (temporary myopia).
- 9 percent reported dry eye, irritated or burning eyes, or other eye strain.
- 8 percent reported difficulty refocusing from one distance to another or experiencing a headache
- About 4 percent reported blurry vision at close or intermediate distances (temporary hyperopia).
Another study found that about 20 percent of regular computer users experienced transient myopia, or temporary nearsightedness, after an extended period of using their computers. This is caused by accommodative problems involving the middle structures of the eye, like the lens, and surrounding eye muscles, which are overworked to focus on the specific task in front of you.
Other problems can be caused by ocular surface mechanisms. Extended periods of suffering from dry eyes due to not blinking enough can increase irritation and inflammation, which may trigger further conditions including uveitis.
Poor sleep quality and insomnia are other issues associated with digital eye strain. One study found that 80 percent of Americans report using digital devices, including television, at least an hour before going to bed. The blue light emitted from such devices can trigger a stronger sense of wakefulness in the brain, which reduces the ability to fall asleep or stay asleep. About 55 percent of people use some kind of digital screen within an hour after they wake up, which contributes to a higher risk of eye strain throughout the day.
Changes to underlying vision problems (from refractive errors like farsightedness or myopia), inadequate focusing in the eyes or eye coordination problems, and aging eyes, including the development of presbyopia, can all contribute to an increased risk of strain when using a computer for a lengthy period of time.
These treatments and prevention approaches can help:
- Try the 20-20-20 Rule. Work on a digital screen for 20 minutes; then, take a break for 20 seconds, preferably looking at something 20 feet away. This will give your eyes a needed break.
- Check your setup. Adjust the level of your screen in relation to your eyes, along with how your workspace is set up, to reduce the overall strain on your body, not just your eyesight. Sitting about arm’s length, or 25 inches, from your computer screen is the recommended safety distance.
- Consider antiglare screens. Antiglare screens can help to reduce or prevent CVS.
- Assess light levels. Making sure the light level in the room around your workspace is appropriate can help to manage eye strain.
- Take short breaks to blink. When you use a computer screen for a long time, you may not blink enough because you are concentrating on your work. This can lead to dry eye, which may be temporary. On a long-term basis, it can cause irritation and inflammation of the eye.
- Apply eye drops. These can help if your eyes feel too dry, itchy, or irritated. If you have chronic dry eye, you may consider using a humidifier for the room.
- Have your vision checked. You may need an updated glasses prescription.
- Consider blue-light glasses. There are specific lenses for glasses that reduce the amount of blue light from computer screens that hits your eyes, which can reduce eye strain and improve sleep because it does not impact the circadian rhythm as much after dark.
- Try vision training. If you follow your optometrist’s instructions and have made lifestyle changes to manage computer vision syndrome but are still struggling with pain, blurry vision, and dry eye, you may need to undergo visual therapy called vision training. This is a structured program that teaches you routines and exercises to improve your visual abilities, especially while you work.
How to Limit Your Child’s Screen Time
In today’s increasingly digital world, parents can find it very difficult to limit their children’s screen time. While there isn’t a set amount of screen time that is recommended to protect the eyes, excessive use of screens has been linked to higher rates of myopia, digital eye strain, and sleep issues.
Here are some tips to limit your child’s use of screens:
- Set boundaries. Establish clear rules with your child for the amount of screen time they can have on a daily or weekly basis.
- Create “safe” zones. Designate areas of the house, like the kitchen or dinner table, that are free of electronics.
- Model good behavior. Put your phone away more often. Your kids will follow your lead.
- Use parental controls. There are many apps that can regulate use on phones, tablets, and computers. Set these up so you aren’t guessing about the amount of time your child uses electronics.
- Set hours. To promote good sleep, it’s a good idea to limit the use of electronic screens in the hours before bedtime.
- Get outside. Kids move less when they are on screens too much. Encourage other activities, particularly those that get them outside and moving.
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Understanding and Preventing Computer Vision Syndrome. (December 31, 2008). Malaysian Family Physician.
Eyestrain: Overview. (October 18, 2018). Mayo Clinic.
Visual and Ocular Effects From the Use of Flat-Panel Displays. (June 18, 2016). International Journal of Ophthalmology. Digital Eye Strain. The Vision Council.
Screen Use for Kids. (June 2021). American Academy of Ophthalmology.