Computer vision syndrome (CVS)/Digital Eye Strain (DES)

This is perhaps the most relevant topic in todays era. I get so many queries on this issue ,hence decided to write this article for your benefit. Screens have become an integral part of everyone's life and they are here to stay. Be it entertainment, work, education we are spending more and more time on gadgets. Unlike the general impression that screens are bad for eyes ,its our wrong habits while using them that cause eye problems. CVS or DES is a term that describes eye related problems and the other symptoms caused by prolonged screen use. 

What are the symptoms of digital eye strain?

Visual: intermittent blurring, Slow refocusing, Light sensitivity
Asthenopic: Eye strain ,Headache ,Eye fatigue, Tired eyes

  • Ocular: Irritation, itching, redness, burning sensation, Tearing, contact lens discomfort
  • Systemic: Tension, Fatigue, Irritability, Nervousness, Errors due to focus loss, Drowsiness
What causes these problems?
  1. Constantly gazing at a near distance (at the monitor/mobile screen)
  2. Decreased rate of blinking
  3. Convergence Accommodation Fatigue
  4. Contrast /Brightness /Glare of screen

When we look at a near object both our eyes move towards each other (converge) to fixate at the target. Prolonged viewing of the monitor at close distance leads to fatigue of accommodative convergence and its weakness / insufficiency. This consequently leads to eye strain, pain and headache.
Decreased rate of blinking while working on computers leads to instability of the tear film of the eyes. This leads to feeling of dryness, irritation, redness and a reflex watering from the eyes.

Does the type of screen matter ? TV vs Computer vs Ipad vs Mobile?

Handheld devices differ from computers in viewing position and distance, screen size,luminance, and patterns of use.
Accommodation /Convergence is altered more with handheld device like mobiles and tablet use. So computers and TV may be a bit better then mobiles/tablets in terms of eyestrain/eye fatigue.
Reduced blink rate /amplitude and Tear film instability are consistently reported with all devices.

What is the solution?
  1. Proper Visual Hygiene
    • Monitor should be placed about 2-3 feet from the eyes (or at the farthest comfortable distance).
    • Do not gaze constantly at the monitor for long duration. Take your eyes off the screen every 10 minutes. Close your eyes for 20secs every 20mins
    • Every half an hour or so close your eyes for 1-2 minutes to give them rest.
    • Every hour take a 5 minutes break (stand &stretch or run some errand).
    • Make a conscious effort to blink more frequently as n when u can. Avoid sitting in front of an air conditioner facing its air draft while working on computer.
  2. Convergence Exercises
  3. If you are having eye fatigue /headaches, visit an ophthalmologist .She will examine your eyes to see if there is a refractive power or if the convergence muscles are weak. Wear proper prescription spectacles if required. Regular eye exercise can help to improve them .These exercises are advised for all computer professionals, students, office workers, etc.

  4. Lubricant Eye Drops
  5. Lubricant eye drops instilled 3-4 times a day help in soothing the eyes and relieving irritation and redness. Many preservative free eye drops are available in the market. These can be safely used on a long term basis also

How to do convergence exercises?

Sit on a chair upright and look at a far off small object. Hold out a pen at level with your eyes at an arm's length and look at its tip.Gradually bring the pen close to your eyes to a point where you feel a mild strain on your eyes. The tip of the pen should remain clear and single in appearance. Hold the pen in this position for about 5 secs and then again take it back to an arm length. Hold it here again, and then again bring the pen gradually close to your eyes.Repeat above step 10 times and then again look the far off small object. Again repeat the whole sequence.
In the beginning this exercise should be done for 5-10 minutes just once a day in the morning at a time when you are fresh and rested. After one week it should be increased to twice daily. Avoid doing the exercise when you are tired or are having a headache. In the initial period when you begin exercising the pain in the eyes and headache may increase, but this should not discourage you. As you continue the exercise you will gradually feel relief from the symptoms over 2-3 weeks.Continue the exercise for 2 months to build good eye muscle strength and reserves power.

Any tips on how to use computers/ laptops to minimize eye and body fatigue?

To avoid Glare : Reflections off your monitor can make your eyes tired.

  • Reposition your monitor so you don't have windows directly in front or behind your monitor
  • Adjust the brightness and contrast as per your comfort level
  • Regular fluorescent lights emit blue light, which makes it difficult for the eyes to focus, changing the color of the light can make the eyes more relaxed.
  • One can use a glare filter on screen
  • Large monitors are easier to see, font size can be increased
  • Keep your screen free of dust and smudges

To avoid Musculoskeletal issues: Neck pain, Backache, Wrist or arm stiffness

  • Keep monitor at eye level and at an arms length
  • Armrest- A soft, rounded edge so that wrists, elbow, forearms can be supported Keyboard / Wrists: Straight wrists & extended or closer to body with 0 - 20 up
  • Feet firm on the ground (sole & lower leg 90º) /angle b/w upper & lower arm ~ 90º
  • Back tilt- upper torso slightly bent backwards from the computer, firm upright support
  • Cushion for lower back support
Should You Be Worried About Blue Light and Computer Radiation?

NO! The amount of radiation coming from a computer /TV has never been demonstrated to cause any eye disease. A study reprinted by the National Library of Medicine found no measurable UVA or UVB radiation from computer monitors. The Radiation Protection Program at the Massachusetts Institute of Technology summarizes current research about computer monitors’ radiation by saying that "there are no data to suggest a health risk from exposure to the electromagnetic fields associated with the use of monitors."
There is evidence that blue light can interfere with humans circadian rhythms , making it harder to fall asleep. For some people, it can be a good idea to limit screen time before bed Or to filter out blue light from screens before bedtime using the night mode on smart phones to sleep better.

Do blue filter computer glasses work?

No ! Its a optical market driven fad. The internet is full of advertisements and articles on this but look at the source . There is no scientific validation. The experimental studies quoted are done on rats/mice exposed to very intense blue light ,close to eyes for hours and days or human retinal cells on a petri dish. In real time, there is hardly any measurable blue light emitted from screens (proven by spectro radiometer)which reaches eyes the retina cells are not directly exposed, cornea /lens before them cut off maximum blue light. Also by common sense you would understand that sun having the maximum blue light component would have been a much bigger threat then screens. If that doesn’t cause damage in all our eyes (due to various natural filters in eye ) how can screen radiation have long term effect .

For any persisting eye issue when on screens , it is best to visit an ophthalmologist and seek guidance. For any further query/ assistance, you can drop a mail to me: parul_ms@hotmail.com
- Dr Parul Maheshwari Sharma