Computer Vision Syndrome

Computer Vision Syndrome

Computer Vision Syndrome

   Written by Seamus Flynn, Optometrist

Computer vision syndrome is a group of eye related symptoms that occur as a result from over exposure to blue light from digital devices such as smartphones, tablets and laptops. It is also know as digital eye strain.  

This is not a new phenomenon but the incidence has been growing rapidly particularly over the last year and it corresponds directly with the increase in usage of digital devices.

The more digital devices used and the longer the time spent on screens the more severe the symptoms of computer vision syndrome are.


Blue light emitted from LED digital screens have high energy wavelengths which causes a stress on the visual system. When viewed for two hours or more a day it leads to symptoms of digital eye strain as the eyes are not able to recover adequately from the constant tension and muscle contractions necessary to maintain focus on an object at a close distance. Viewing a computer screen differs significantly to reading from a book as the text is not as defined, the contrast is usually poorer, and the viewing angles vary considerably. All of these issues can lead to symptoms of CVS as the eyes and the visual system has to work harder to be able to see clearly.

Other Causes include

  • Insufficient lighting
  • Glare from the screen.
  • Incorrect viewing distances.
  • Poor seating posture.
  • Uncorrected vision problems.




The symptoms of CSV are

  • Eyestrain,
  • Sore, Burning Eyes
  • Blurred vision.
  • Increased sensitivity to light
  • Dry eyes.
  • Sore neck shoulders or back

 computer vision syndrome blue light glasses


Computer vision syndrome can be diagnosed by your optometrist during an eye examination.

Your optometrist will take a detailed medical and lifestyle history. They will check your exposure to digital devices and question about your working distance, posture, lighting conditions, quality of the screens used and other environmental factors

They will then do a refraction test to see if there is any uncorrected visual problems such as short sightedness or far sightedness.

Next they will do a binocular vision assessment to see if both eyes are working well together. Checking if they converge together and fully and if they are both synchronized well in terms of focus and movement in all gazes.

In some cases cycloplegic eye drops may be used to paralyse the ciliary muscle in order to get a better idea of how the eyes are working, moving and focusing together.



Treatments of computer vision syndrome usually revolve around treating the underlying cause.

If an eye examination reveals an uncorrected prescription for close work than glasses should be worn while using digital devices.

If there are binocular vision problems then exercises or surgery should be advised to correct the insufficiencies.

Wearing blue light glasses blocks the harmful, high energy blue wavelengths from the screens which causes a stress on the visual system and leads to the symptoms of visual eye strain.

Fixing any environmental causes such as lighting problems, the position of the screen, glare or poor posture can also help alleviate symptoms.



The 20-20-20 rule is a very useful rule to follow when using digital screens for prolonged periods of time.

It states that for every 20 minutes of work on a digital screen you should take a 20 second break and look up and focus on an object at least 20 yards away.

This will relax the muscles that are constantly working in order to remained converged and focused at the digital screen.

Make sure that you are wearing corrective lenses if you have a prescription, that your posture is good, you have good lighting and that you are wearing blue light glasses if using a screen for two hours or more a day.

Another important thing to consider is blinking more often.

When we do close concentrated work we unconsciously blink far less than when we are looking in the distance. This results in our eyes getting dry and irritated as we are not replenishing or tear film as much as usual. That is why it is a good idea to consciously blink more than you normally would if you are using digital screens and it will make your eyes more comfortable.



A 2021 study (1) showed that 98% of undergraduate medical students suffered from a least one symptom of computer vision syndrome within the last three months. 

As we are using digital devices more and more in our work, school and home lives which makes it even more important for people to be aware of the prevention methods of computer vision syndrome.