Computer Vision Syndrome

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Computer Vision Syndrome
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(No Transcript)
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What is Computer Vision Syndrome? (CVS)

• A complex of eye or vision problems which are
  experienced during and related to computer use.

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Superior and lateral rectus muscles, optic nerve.
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Superior and inferior oblique muscles,
superior,inferior, and lateral rectus muscles,
with eye.
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Superior and inferior oblique muscles, medial and
inferior rectus muscles.
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Eye with rectus muscle attachments.
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Why are we concerned about CVS?

• 143M American workers work on a computer and
  estimates are
• - 88 suffer from computer eyestrain
• 90 of the 143M U.S. workers use computers today
  for more than 3 hours per day.
• This problem effects productivity by 4 to 19 .

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What are the symptoms of CVS?

• Eyestrain (sore or fatigued eyes)
• Headache
• Slowness in changing focusing distance
• Eye irritation (burning, dryness, redness)
• Neck, back shoulder pain

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The Problem

• It has multiple causes symptoms.
• Prolonged viewing is the most common cause and it
  has been proven to be unnatural for the human
  optical system.
• Humans blink approximately 22 times per minute.
  During computer use humans blink only 4 to 6
  times per minute.

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Other Problems

• Lower blinking rates cause eye moisture to
  evaporate (dry eye).
• Dry eye causes people to arch their foreheads in
  a effort see better, thus causing headaches.
• Many people assume awkward, unnatural postures,
  thus causing sore backs, stiff necks hurting
  shoulders.

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FAQs

• What Causes Computer Vision Syndrome?
• CVS is caused by our eyes and brain reacting
  differently to characters on the screen than they
  do to printed characters.

Our eyes have little problem focusing on most
printed material, which is characterized by dense
black characters with well-defined edges. Healthy
eyes can easily maintain focus on the printed
page. Characters on a computer screen, however,
don't have this contrast or well-defined edges.
These characters (pixels) are brightest at the
center and diminish in intensity toward their
edges. This makes it very difficult for our eyes
to maintain focus and remain fixed onto these
images.
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FAQs

• Will Glare Screens Prevent CVS?
• Glare screen filters may help somewhat, but they
  will not solve your computer vision problems
  because they only affect glare from the computer
  screen not the visual problems related to the
  constant refocusing of your eyes when working at
  a computer.
• Only when your eyes can focus clearly at the
  plane of proper distance on the computer screen
  can they experience relief from the fatiguing
  effects of CVS. An anti-reflective coating (AR)
  is also highly recommended on all computer
  eyeglasses. An AR coating prevents glare and
  reflections on the front and the back of the
  lenses that would interfere with focusing on the
  screen.

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FAQs

• Will Computer Eyeglasses Make the Screen Clearer?
• Yes, because they will eliminate the constant
  refocusing effort that your eyes go through when
  viewing the screen. It has also been proven
  clinically that having the correct prescription
  in computer eyeglasses increases productivity and
  accuracy.

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FAQs

• What About the Tints I've Heard of for Computer
  Lenses?
• If you work in a brightly lit office, you may
  benefit from a light tint applied to your
  computer lenses. This can cut the amount of light
  that reaches your eyes and provide relief in some
  cases. But tints and filters don't address the
  underlying cause of computer eyestrain.

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FAQs

• Does Every Computer User Need Computer Glasses?
• More than 70 of computer users need computer
  eyeglasses. In fact, according to a study out
  of the University of California, Berkeley,
  25-30 of children would benefit from computer
  eyewear.

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FAQs

• Will My Reading Glasses Work at the Computer?
• Not necessarily. In most cases your reading
  glasses are probably not going to do the job. The
  correct computer eyeglasses will optimize your
  comfort and productivity at the computer screen
  while also allowing you to read and see out at
  some determined distance (10-13 feet). Reading
  glasses are usually prescribed to read at a
  distance of 16"-18", but computer glasses are
  usually designed to work at 18" to 28".

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FAQs

• Can CVS Cause Other Body Pains?
• Headaches, sore neck, shoulders or back are
  common complaints and there are two main causes,
  one having to do with your vision and one not.
• Vision
• So where do the other aches and pains come in?
  These are often caused by trying to read the
  screen through the bottom portion of bifocals, or
  though half-eye reading glasses. You tip your
  head up or lean forward to see and this unnatural
  posture makes you sore.

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FAQs

• Isn't Ergonomics the Solution to Computer
  Eyestrain?
• Ergonomics is important changing one's computer
  workstation can certainly help to minimize other
  physical symptoms. But ergonomics cannot fix a
  visual problem. The proper prescription computer
  eyeglasses at the proper computer distance (18"
  to 28") is most important. This can be done only
  with the right computer lens prescription.

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10 Steps to Reducing Computer Eyestrain

• Get a computer eye exam.
• Use proper lighting.
• Eyestrain is often caused by excessively bright
  light coming in from outside and excessively
  bright light inside. When you use a computer,
  your ambient lighting should be about half that
  used in most offices. Eliminate exterior light by
  closing drapes, shades, or blinds. Reduce
  interior lighting by using fewer light bulbs or
  fluorescent tubes, or use lower intensity bulbs
  and tubes. If possible, position your monitor so
  that windows are to the side of it, instead of in
  front or back.

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10 Steps to Reducing Computer Eyestrain

• Minimize glare.
• You may want to install an anti-glare screen on
  your monitor and, if possible, paint bright white
  walls a darker color with a matte finish. Again,
  cover the windows when outside light cannot be
  reduced, use a computer hood. Have an
  anti-reflective coating applied to your glasses.
  This will prevent glare and reflections on the
  back side of your lenses
• Adjust the brightness of your computer screen.
• Closely match the brightness of the environment
  with that of your computer screen. Make sure that
  the text size and color are optimized for the
  most comfort.

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10 Steps to Reducing Computer Eyestrain

• Monitor Display Quality
• Refresh rate how often your monitor redraws
  the content on the screen. A too-low rate can be
  hard on your eyes, and a very slow rate causes a
  noticeable and irritating flicker.
• Resolution a monitor's pixel density the
  more pixels, the higher the level of detail.
  Generally, the higher the resolution the better.
• Dot pitch affects the sharpness of the
  display. The lower the number, the sharper the
  image. Most monitors have a dot pitch between
  0.25 mm (millimeters) and 0.28 mm 0.28 or lower
  is desirable.

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10 Steps to Reducing Computer Eyestrain

• Blink more often.
• Blinking is very important when working at a
  computer it rewets your eyes to avoid dryness
  and irritation. When working at a computer,
  people blink less frequently about five times
  less than normally, according to studies. Tears
  coating the eye evaporate more rapidly during
  long non-blinking phases and cause dry eyes .
  Office buildings may have excessively dry
  environments that also reduce tearing.
• Also try this exercise Every 30 minutes blink 10
  times by closing your eyes as if falling asleep
  (very slowly). This will help rewet your eyes
• Exercise and stretch your eyes.
• An hourly exercise to readjust your focusing is
  to look far away at an object for 10-15 seconds
  and then near for 10-15 seconds, rocking your
  focusing back and forth between near and far. Do
  this 10 times. Both of these exercises will help
  you prevent strained near vision and stretch your
  focusing muscles

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10 Steps to Reducing Computer Eyestrain

• Take frequent breaks.
• 20/20/20 every 20 minutes look at something at
  least 20 feet away for 20 seconds.
• Every 50 minutes on a computer, change tasks for
  10 minutes.
• Modify your workstation.
• If you need to look back and forth between a
  printed page and your computer screen, this can
  cause eyestrain. Place written pages on a copy
  stand adjacent to the monitor. Properly light the
  copy stand you may want to use a desk lamp, but
  make sure it doesn't shine into your eyes or onto
  the computer screen. Adjust your workstation and
  chair to the correct height. Purchase ergonomic
  furniture to insure proper screen locations and
  posture.

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10 Steps to Reducing Computer Eyestrain

• Exercise even when sitting.
• Anyone in a sedentary job, especially those using
  computers, should stand up, move about, or
  exercise their arms, legs, back, neck, and
  shoulders frequently. NIOSH recommends several
  sitting, stretching, and joint rotating exercises
  for computer users

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The Solution

• Keep computer screens slightly below eye level
• 20-26 inch from the screen
• Keep contrast brightness at moderate levels
• Keep screen clean
• Reduce screen glare
• Frequent short breaks
• Purposely blink rapidly

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Our eyes involuntarily move to the RPA, and then
strain to regain focus on the screen. This
continuous flexing of the eyes' focusing muscles
creates fatigue and the burning, tired-eyes
feeling that is so common after long hours at the
computer.