In the modern world, computer use is almost universal. Since a lot of today’s jobs involve prolonged computer use, people have more exposure to screen time than ever before. The high prevalence of vision-related problems among visual display units (VDU) workers adds another worry for many employers. As our society continues to move towards even greater use of computers, we can help employers ensure that their employees stay healthy and productive. Keeping up to date with all the research is essential to staying competent and being a great resource for your clients. There’ve been a large number of studies focused on visual discomfort in visual display unit (VDU) workers. So in this post, we’re going to look at some of the recently published studies about VDU that I think are interesting and useful for you to know.

Why You Should Leverage These Studies

Before I dive into the discussion, I just want to tell you first why I want to talk about this. For many of us Ergonomics Consultants, I know that there's a really common situation that can happen, especially when you're first starting out: people don't know that you exist and that you’re the go-to expert for ergonomics in your city. That's what I want to shed light on today’s post by giving you some up-to-date information that you can put in your back pocket when you’re talking to prospects in your city, conducting an ergonomics assessment, or doing a lunch-and-learn in the organization you’re working with. There are so many ways you can leverage the research that I'm going to share with you below.  Let’s start!

Computer Vision Syndrome (CVS)

Most people nowadays have jobs that require sitting in front of a computer screen for long periods of time. That can place serious strain on your eyes. This increase in exposure to digital screens comes with an increase in eyestrain and other vision problems related to computer vision syndrome (CVS). CVS is the most common workplace hazard today, which affects 60 million people around the world, and there’s an increase of one million cases of CVS each year.

Many causes of CVS are thought to be the result of poor ergonomics. In fact, this study revealed that excessive computer exposure, poor ergonomic practices, and improper viewing angle are the ergonomic risk factors that contributed significantly to the development of CVS. Interestingly enough, the researchers found that less than 3 hours of computer use was associated with lesser risk of developing CVS. This particular study is focused on CVS among bank workers, and the findings showed that bankers had a high prevalence of CVS (72%). The most reported symptoms were headaches (73.4%), eyestrain (65.5%), and itching (63.3%). Additionally, female bankers were almost three times more likely to be associated with CVS.

Most research about CVS is centered on analyzing occupations related mainly to office work. Nurses and other healthcare professionals are also exposed to digital screens like tablets and laptops in hospitals, but very few published studies have explored the effects of VDU exposure on the visual health of healthcare workers. This one significant study analyzed the implications of CVS on healthcare workers. 

The key themes that emerged from this study included:

  1. Healthcare workers are more susceptible to CVS. The prevalence of CVS was 56.75%, with nurses being the most affected occupational group (61.75%). 
  2. Being a woman also doubles the probability of experiencing CVS in nurses. It’s associated significantly with female sex and morning shifts plus on-call in the physicians and surgeons group. 
  3. A seniority between 10 and 20 years is one factor that affects the CVS in this occupational group.
  4. Difficulties in handling the software applications (which require high concentration and intense visual demands) were another risk factor for the CVS in the nurse group.

I know that CVS is more of an occupational hazard, but it doesn’t only affect those who work in front of a computer for long hours. The major risk factor for CVS is excessive use of digital devices, and CVS related to online classrooms during the lockdown further accentuated this problem. That’s why it’s also important to look at the prevalence of CVS among the adolescent population. This one study I found shared some interesting findings about CVS in students. Here are the results:

  1. The awareness of and practices for using digital devices and preventing CVS were poor in more than half of the college students in the study. 
  2. Health students had better knowledge than other students. 
  3. Those using a smartphone as their main device had worse knowledge than users of other devices. 
  4. The digital device usage norms showed better practices by females and health students than males and students in other departments.

Preventative Measures for CVS Symptoms

There are several things VDU users can do to reduce the effects of CVS. A few small changes can help ease the symptoms and avoid new problems. Firstly, adjusting your workstation to achieve proper posture is important. You can also tweak your PC settings by adjusting the brightness, contrast, and font size until you find what’s comfortable for you. People tend to blink less often when using a computer, which can result in tear film instability and ocular inflammation, promoting dry eye disease (DED). Taking frequent breaks and blinking regularly allows you to refocus on texts without straining your eye muscles. 

In a recently published study, researchers evaluated different methods for preventing VDU-associated DED and ocular discomfort and assessed their effectiveness. The results of this study showed that most preventive measures for VDU-related DED were aimed to increase blink rate or directly prevent tear film instability, ocular inflammation, mucin loss, or ocular surface damage. Using an adjustable chair, taking frequent breaks, ergonomic training, blink animations, and omega-3 supplementation also improved the symptoms of DED. 

Using special pairs of computer glasses can also help prevent CVS, especially for those who have vision problems. In recent years, new spectacle lens designs with a progressive power profile have been introduced for pre-presbyopes with CVS. These “accommodative support” (AS) lenses are a low-add progressive addition spectacle lens designed to ease symptoms in CVS. This one study aims to investigate three things: if AS lenses improve CVS symptoms, if binocular vision and accommodative functions predict a benefit from AS lenses, and if wearing AS lenses for 6 months impacts on binocular and accommodative functions. Like any other studies, this study used a questionnaire to assess CVS. The researchers applied the Computer Vision Syndrome Questionnaire (CVS-Q), developed by a Spanish group. The result of this research study revealed that:

  1. Very few of the optometric variables correlated significantly with the improvement in CVS-Q scores after wearing AS lenses for 3 and 6 months. 
  2. Over 3 months and 6 months, the improvement in CVS-Q is no greater in those wearing accommodative support (AS) lenses than in a control group (Single Vision). 
  3. Immediately on changing from SV lenses to AS lenses, most of the control group reported a preference for AS lenses.
  4. AS lenses don’t have any adverse effects on accommodative or binocular function.

Assessing CVS

There are several questionnaires experts use to assess the severity of CVS. Aside from the CVS-Q, another popular option is the 17-Item Computer Vision Symptom Scale Questionnaire (CVSS17). This next study aims to validate the Italian version of the 17-item Computer Vision Symptom Scale questionnaire. The results of the study suggest that the questionnaire has good validity, discriminatory power, internal consistency, and reliability. The test can be applied to measure the vision-related quality of life in VDU users in an Italian setting both for clinical and research purposes. So if you’re interested in using the CVSS17 or CVS-Q, by all means, check it out. Or leave a comment below if you've ever used this tool before. 

In another study, the psychometric properties of the Italian version of the CVS-Q, the CVS-Q IT, was also validated using Rasch analysis. The CVS-Q IT is the first linguistic, validated version of the original CVS-Q. Their findings indicate that the CVS-Q IT is a simple, valid, and reliable scale for the assessment and diagnosis of CVS in the adult digital-device-using population in all types of studies. So if you're interested in diagnosing digital eye strain, then I want to encourage you to check out this study. 

And that’s it! I hope you get better insights about the effects of VDU use and tools to assess CVS from this post. Use these studies the next time you talk to your clients so you can make better recommendations and be a great resource for them.

If you’re interested to see more up-to-date research, the Accelerate program could work for you. We release curated literature reviews about ergonomics every month. Accelerate members really love this because it saves them time and money to constantly search and find peer-reviewed research. But the curated literature review is just one of the five offerings that you'll get when you enroll in the Accelerate. To see what else this program has to offer, just head here to sign up



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