Much of our days, we use screens of all sizes for work, shopping, finances, entertainment and more which improves the quality of our lives. Screen use has been steadily building over decades. Clearly, as is often the case with most tools, there are safe and unsafe ways to work with screens which are integrally correlated to our health, wellbeing and productivity.
“Viewing a computer or digital screen often makes your eye muscles work significantly harder. As a result, the unique characteristics and high visual demands of computer and digital screen viewing make many individuals susceptible to the development of vision-related symptoms.” Equally important to seasoned safety professionals is how, quite often, many people will tilt their heads at odd angles or they bend toward the screen in order to see it clearly. These prolonged awkward postures often result in pain in the neck, shoulder or back.
Computer Vision Syndrome (CVS), also known as Digital Eye Strain (DES), is a condition which often results from chronic unmanaged use of digital devices such as computers, smartphones, and tablets due to the repetitive need for viewing text and images often at very small scale.
Even in this Age of Wellbeing in the workplace, including all of it’s benefits for employees and employers well-understood, unfortunately, most experts find CVS prevalent, among the top five threats to Knowledge Worker Wellbeing. In fact, a growing number of experts agree that Computer Vision Syndrome holds the distinction of being called the number one occupational hazard for knowledge workers of the 21st century, see below.
Common CVS Symptoms
- Eye strain and discomfort
- Dry eyes or excessive tearing
- Blurred or double vision
- Headaches, migraines
- Neck, back and shoulder pain
Your intrepid author, also now managing CVS after ignoring it too long, came across an illuminating study recently published in Nature: “Prevalence of Computer Vision Syndrome: A Systematic Review and Meta-Analysis“. More than a one-off individual study, this was a painstaking comprehensive meta-analysis reviewing the most recent 745 research studies on the topic from 20 countries.
From this study “The pooled prevalence of computer vision syndrome was determined to be around 66%“. Generally, two of every three of your coworkers has some degree of Computer Vision Syndrome. The study continued “Although computer vision syndromes are becoming a major public health concern, less emphasis is given to them, particularly in developing countries.“
Some helpful framing of the issue from the study includes:
- The massive growth of digital devices has become an integral part of daily life, and millions of individuals of all ages are at risk of CVS.
- In developed nations, engagement with digital devices has increased substantially in recent years across all age groups.
- Digital device use has increased in developing countries, resulting in a high burden of CVS due to low accessibility, low utilization of personal protective equipment, and limited break time while using electronic devices.
- CVS is a major public health problem leading to occupational hazard, an increased error rate, impaired visual abilities, reduced productivity, and low job satisfaction.
- A review of the literature showed that factors associated with CVS can be classified as personal factors, which include poor sitting position, inappropriate eye-to-screen distance, insufficient working procedures, improper viewing angle and distances, age, medical diseases, and long duration of computer usage.
- The environment and computer factors such as improper workstations, poor lighting, contrast, and resolution rooms, slow refresh rate, glare of the display, excessive screen brightness, and imbalance of light between the computer screen and surrounding working room.
- CVS has an effect on reduced productivity and visual and musculoskeletal impairment and a negative impact on cardiac rhythms and sleep patterns.
What is it about Blue?
Another related issue concerns “blue light“. Blue light is everywhere, including in sunlight. Computer and laptop screens, flat-screen televisions, cell phones, and tablets use LED technologies with high amounts of blue light.
As far as blue light contributing to CVS, studies haven’t produced any compelling evidence although you’ve probably noticed that the world’s largest equipment manufacturers now offer software to adjust the amount of blue light emitted from their screens. You can even find that on your iPhone.
This is because there have been a number of significant studies producing evidence that blue light certainly guides our body’s circadian rhythms (our natural wake and sleep cycles). During daylight, blue light from the sun wakes us up and stimulates us. Too much blue light exposure at night from your phone, tablet or computer, however, makes it harder to get to sleep.
Now that we’ve dutifully mentioned blue light, we’ll leave that for future studies and return to the very well-understood and studied realm of CVS.
CVS Scope and Depth
While the list of CVS studies is long, another recent article on the topic from The American Optometric Association (AOA): Computer Vision Syndrome confirms the scope and depth of the issue for knowledge workers. Guidance from the article includes:
- Many individuals experience eye discomfort and vision problems when viewing digital screens for extended periods.
- The level of discomfort appears to increase with the amount of digital screen use.
- The average American worker spends seven hours a day on the computer either in the office or working from home.
- Viewing a computer or digital screen is different than reading a printed page. Often the letters on the computer or handheld device are not as precise or sharply defined, the level of contrast of the letters to the background is reduced, and the presence of glare and reflections on the screen may make viewing difficult.
- At greatest risk for developing CVS are those persons who spend two or more continuous hours at a computer or using a digital screen device every day.
- Some individuals may experience continued reduced visual abilities, such as blurred distance vision, even after stopping work at a computer.
- Important factors in preventing or reducing the symptoms of CVS have to do with the computer and how it is used.
- This includes lighting conditions, chair comfort, location of reference materials, the position of the monitor, and the use of rest breaks.
CVS and Musculoskeletal Disorders
Further, from the AOA article, “Some people tilt their heads at odd angles because their glasses aren’t designed for looking at a computer or they bend toward the screen in order to see it clearly. Their postures can result in muscle spasms or pain in the neck, shoulder or back.“
This is consistent with other studies shared in previous articles where it’s been confirmed how people often adjust their posture to compensate for visual challenges encountered while working at their computers.
You probably already know that prolonged awkward and static postures are very highly correlated with increased risk and reported injury.
CVS Mitigation, Best Practice Behaviors
In the AOA article and in most other articles from experts in the field, you’ll find Mitigation Strategies include:
- Location of the computer screen. Most people find it more comfortable to view a computer when the eyes are looking downward. Optimally, the computer screen should be 15 to 20 degrees below eye level (about 4 or 5 inches) as measured from the center of the screen and 20 to 28 inches from the eyes.
- Reference materials. These materials should be located above the keyboard and below the monitor. If this is not possible, a document holder can be used beside the monitor. The goal is to position the documents, so the head does not need to be repositioned from the document to the screen.
- Lighting. Position the computer screen to avoid glare, particularly from overhead lighting or windows. Use blinds or drapes on windows and replace the light bulbs in desk lamps with bulbs of lower wattage.
- Anti-glare screens. If there is no way to minimize glare from light sources, consider using a screen glare filter. These filters decrease the amount of light reflected from the screen.
- Seating position. Chairs should be comfortably padded and conform to the body. Chair height should be adjusted so the feet rest flat on the floor. Arms should be adjusted to provide support while typing and wrists shouldn't rest on the keyboard when typing.
- Rest breaks. To prevent eyestrain, try to rest eyes when using the computer for long periods. Resting the eyes for 15 minutes after two hours of continuous computer use.
- Eye exercises. For every 20 minutes of computer viewing, look into the distance for 20 seconds to allow the eyes a chance to refocus.
- Blinking. To minimize the chances of developing dry eye when using a computer, try to blink frequently. Blinking keeps the front surface of the eye moist.
The risk mitigation list above is practical and doesn’t involve large expense. Beyond the basic workstation improvements, you probably already know that the best defense against threats to knowledge worker wellbeing is helping them learn automatic healthful behaviors.
The only remaining question involves how do you help the people you’re responsible for to learn to make those behaviors into automatic habits to improve their wellbeing.
Science and history have shown that you can improve these safety behaviors through a point-of-use operant conditioning positive reinforcement tool being used.