Computer Vision Syndrome (CVS)

Computer eyes, or Computer Vision Syndrome (CVS), is a collection of eye and facial symptoms that can occur after prolonged use of a screen, such as a computer, tablet or smartphone. It is not an eye disease in itself, but a combination of symptoms related to the way your eyes function whilst using a screen.

When you look at a screen, your eyes have to constantly adjust their focus, move between different distances and cope with glare, contrast and screen flicker. What’s more, you blink much less frequently than usual whilst working at a screen. This causes your tears to evaporate more quickly, which can make your eyes feel drier.

Common symptoms of CVS

Symptoms vary from person to person, but are common among people who spend several hours a day working in front of a screen. Typical symptoms include:

• Tired, heavy or burning eyes
• Dry or irritated eyes
• Blurred or double vision
• Headaches
• Sensitivity to light
• Difficulty focusing
• Tension in the neck, shoulders or back

The symptoms are usually temporary and subside after a period of rest, but may return when working at a screen again. In people who already wear contact lenses or are prone to dry eyes, the symptoms may be more severe.

Causes and risk factors

CVS is caused by a combination of factors. The distance from the screen, posture, lighting, screen glare, sub-optimal spectacle prescription and the duration of screen-based work all play a part. Humidity, air conditioning and draughts can also contribute to dry eyes whilst working.

People with uncorrected vision problems, such as short-sightedness, long-sightedness or astigmatism, are at increased risk of developing CVS symptoms. Their eyes have to work harder to see clearly, which leads to fatigue more quickly. Age also plays a role: from around the age of 40, the eye’s ability to accommodate decreases (age-related long-sightedness), making it more difficult to focus at close range.

As far as is known, computer vision syndrome does not cause permanent damage to your eyes. The symptoms are functional and relate to the way you work and how your workplace is set up. Nevertheless, it is wise to pay attention to prevention and ergonomics, especially if you spend long periods in front of a screen every day.

Workplace ergonomics and screen use

A well-organised workspace can help reduce many symptoms. Ensure your screen is at eye level or slightly lower, at a distance of about an arm’s length. Avoid glare by not placing the screen directly opposite a window and, if necessary, use an anti-glare filter. Ensure there is sufficient and even lighting in the room, without harsh contrasts.

Adjust the brightness and contrast of your screen so that it is comfortable to read, and increase the text size if necessary. Take regular breaks following the 20-20-20 rule: every 20 minutes, look at something at least 20 feet (about 6 metres) away for 20 seconds. This helps your eyes to relax and refocus.

Blinking and eye moisture

Consciously blinking more often whilst working at a computer screen helps to keep your eyes moist. If you suffer from dry eyes whilst working, it may help to increase the humidity in the room or reduce draughts and air conditioning. Drink plenty of water and avoid staring for long periods without blinking.

Prescription strength and eye tests

Have your eyes checked regularly by your optician or optometrist, especially if you notice you’re having trouble focusing or if you experience symptoms whilst working at a computer screen. An incorrect prescription or an outdated correction can make the symptoms worse. Some people benefit from special computer glasses, with a prescription tailored to the working distance.

Contact lenses and computer use

If you wear contact lenses and suffer from dry or tired eyes whilst working at a computer screen, it may help to pay attention to the type of lens and how you look after them. Ensure your lenses are clean and fit properly, and do not wear them for longer than recommended. Some people alternate between lenses and glasses, particularly during long working days.

If you have persistent symptoms or are unsure about your eyes or your prescription, please have them assessed by your optician, optometrist or ophthalmologist.