Dangers of CRT Display

25 06 2008

// Well, this article is for those would are still using CRT(Cathode Ray Tube) monitor including me(i am currently using a Samsung SyncMaster 753s). Over the past few years, CRT have been used fewer and fewer in computers. Big companies like Dell, Macintosh, among others have stop the production of CRT displays. CRT displays are cheap but do you really know its dangers?

What is a CRT ?

The technology used in most televisions and computer display screens. A CRT works by moving an electron beam back and forth across the back of the screen. Each time the beam makes a pass across the screen, it lights up phosphor dots on the inside of the glass tube, thereby illuminating the active portions of the screen. By drawing many such lines from the top to the bottom of the screen, it creates an entire screenful of images (definition from webopedia).

The 5 Dangers of CRT (Computer Display)

1. Prolonged use of CRT cause nausea, vomiting, headache and confusion.

2. You can feel extremely tired due to electromagnetic radiation from CRT and can even suffer from memory loss, ringing in the ears and more.

3. Damage your eyes (cataracts, retina damage, eye cancer).

4. Illumination levels can strain and stress the eyes and reduce visual acuity.

5. Some of the larger or long term effects of electromagnetic radiation can include skin rash, nerve damage, joint pain, muscle spasms, digestive problems, blood cells which leak hemoglobin and brain tumors.

Reduce CRT effects of health

Here are some good practices which you must follows if you want to reduce the consequences :

1. Take mini breaks to focus on objects at various distances in the room.
2. Do figure 8 exercise with head letting the eyes change focus as the head moves.
3. Palming exercise – hold palms over eyes.

The palming exercise will teach you to relax your eyes, which in turn will bring healthy energy to your eyes.

First, rub your hands together until they feel warm (about 15 to 20 seconds). Then place your cupped hands over your closed eyes, being careful not to touch your eyes with the palms of your hands. The fingers of each hand should overlap and rest gently on the center of your forehead. Don’t create any unnecessary pressure on your face. If your arms get tired, rest your elbows on a table.

Sit quietly for one to two minutes with your hands over your eyes. The more relaxed you become, the blacker the darkness you will see with your eyes closed.

(More on eyes exercises below)

4. Ergonomics – Set up workstation so screen is level with eyes or at most 10″ down. Please note that bifocal wearers may need to lower monitor a couple of inches.
5. Make sure sunlight or bright lights are not directly behind you so there is no glare.  Better to be at the side.
6. Make sure the screen is not the only illumination in the room – turn on other lights or arrange for natural light.
7. Use a no glare screen

8. Adjust brightness and contrast to optimum comfort.

9. Tilt top of the monitor back 10 to 20 degrees.

Eyes Exercises

Eye Comfort Exercises

  1. Blinking (produces tears to help moisten and lubricate the eyes)
  2. Yawning (produces tears to help moisten and lubricate the eyes)
  3. Expose eyes to natural light


  1. while seated, brace elbows on the desk and close to the desk edge
  2. let weight fall forward
  3. cup hands over eyes
  4. close eyes
  5. inhale slowly through nose and hold for 4 seconds
  6. continue deep breathing for 15-30 seconds

Eye Movements

  1. close eyes
  2. slowly and gently move eyes up to the ceiling, then slowly down to the floor
  3. repeat 3 times
  4. close eyes
  5. slowly and gently move eyes to the left, then slowly to the right
  6. repeat 3 times

Focus Change

  1. hold one finger a few inches away form the eye
  2. focus on the finger
  3. slowly move the finger away
  4. focus far into the distance and then back to the finger
  5. slowly bring the finger back to within a few inches of the eye
  6. focus on something more than 8 feet away
  7. repeat 3 times

We know that our eyes are an important factor in all of our lives. We sometimes take sight for granted but can you imagine not being able to see everyday things normally. These little measures can help to keep your eyes healthy.