Download don`t let them put a strain on you

DON’T LET THEM PUT A
STRAIN ON YOU
By Sue McAteer, CPOT
Computerscan’t live with them, can’t live without them. If
you are one of the millions of Americans who either work or own a computer, laptop, or
a PDA (personal digital assistants) you could be experiencing Computer Vision
Syndrome (CVS). While CVS isn’t a diagnosed disease, the term is useful for
communicating what patients experience on a daily basis.
CVS can be caused by the eyes and brain reacting differently to characters on a screen.
These characters, called pixels, are brightest at the center and diminish intensity toward
the edges. The intensity change makes it very difficult for the eyes to focus and remain
fixed onto these images. This continuous flexing of the eyes may create fatigue, burning
and a tired-eyes feeling that are common after long hours at the computer.
The American Optometric Association defines CVS as “the complex of eye and vision
problems related to near work which are experienced during or related to computer use”.1
There are many compelling reasons why we need to become more aggressive in
diagnosing and treating the ocular and related symptoms that come with computer use.
Symptoms of CVS can be quite varied but generally include some or all of the following:
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Headache – due to eye strain
Aches & Pains – especially of the shoulders and neck due to poor posture
at the computer because the wearer is sitting at an unnatural position or
angle in order to obtain good vision
Dry Eyes – due to reduced blinking
Tired Eyes – due to strain focusing on the screen
Blurred Vision – due to decreased tears and focusing difficulties
Working at a computer requires a great deal of eye movement and eye focusing. The
constant re-focusing effort stresses the eye muscle, leading to computer-related vision
problems. It can impact greatly on individuals’ comfort and productivity, whether they
are at work, school or home.
How can you distinguish between regular eye fatigue and CVS? Do you get headaches
when you use the computer? Or complain about sore neck, shoulder and back? The CVS
diagnosis requires two or more symptoms on a daily basis following computer use, as
opposed to an occasional eye strain and blurry vision.
In order to identify computer-related problems, you need to ask the right questions of
your patient during the case history. Consider using a separate questionnaire that asks
specific questions regarding computer use, such as the working distances of the screen.
The standard reading distance is around 16 inches, but at many computer stations, the
actual working distance of the monitor is much further away. Ask the patient to measure
their distance with a tape measure from their eye to the screen, so that the doctor can
determine the best prescription. You should also inquire about lighting, windows, lamps
and overhead lights because lights reflecting off a screen can cause glare leading to
eyestrain and headaches. Also, poor ergonomic setup is another cause of head, neck,
shoulder and back pain. Make sure the monitor is neither too high nor too low. One’s
arms should be parallel to the floor when typing, and feet should be flat on the floor or
footstool. Maintaining good posture while seated at a desk will help in eliminating some
neck and back problems.
There are many other ways to ease eye strain such as:
 Blink more; their is a tendency to blink less while staring at a screen
 Use lubricating drops to keep the more comfortable
 Take a break every 10 minutes for every hour on the computer. Try to
look at something at a distance to give your eyes a break
 Clean the computer screen
 Increase the font size of the document so that it easier to read
 Use a light screen with dark letters
 Place documents on a holder near the screen, both equal distances from
your eyes
 Eliminate glare. Glare screen filters may help somewhat, but they will not
always solve computer vision problems.
 Recommend anti-reflective coating for computer glasses. An AR coating
prevents glare and reflections on the front and back of the lenses.
Contact lens wearers (especially those over 40) may need to wear glasses over their
contact lenses for computer use. Contact lens wearers need to remember to blink while
they work at their computer. Computer use can result in a decrease of blinking to almost
one third of the normal rate, while the straight-ahead gaze needed to look at a screen
exposes more of the eye to the air. Combined, this causes the eye to dry out and become
itchy much faster than usual, especially when a contact lens is resting on the cornea. If
frequent blinking is not enough to eliminate the dryness, then an optometrist can
recommend the use of lubricating drops especially made for contact lenses.
Getting the right reading aids will also help with CVS. Consider wearing special
computer glasses when working at the monitor. Wearing trifocals or progressive addition
lenses while working at the computer may add to neck and back strain due to the need to
tilt the head back to view the computer through the appropriate portion of the lenses.
KIDS AND COMPUTER VISION SYNDROME
Adults are not the only ones who suffer from computer vision syndrome. The average
American child spends one to three hours per day on the computer doing homework,
talking online with friends and playing games. Many school-aged children have
computer access at home and spend much of their time sitting in front of the computer.
Parents often encourage children as young as two or three years old to use the computer.
Visual demands in school require the integration of a number of different vision skills:
visual acuity (sharpness of vision); visual fixation (eye aiming); accommodation
(focusing); binocular fusion (forming a single image); convergence (turning of the eyes);
field of vision (side vision); and form perception (recognizing shapes). These systems
can be stressed and overworked if not used efficiently. Computer viewing complicates
how children use their eyes in school because these visual skills are not yet fully
developed - making any near point activities that much more difficult.
Studies have shown that computers can have a negative impact on a child’s vision. Many
children who use computers need corrective eyewear to work comfortably at the
computer at home or in school.
Children can experience many of the same symptoms related to computer use as adults.
Sitting for hours in front of a computer screen stresses a child’s eyes because the
computer forces the eyes to focus and strain a lot more. Because most children work at a
computer either at home or school each day, we are seeing vision problems that were not
known years ago.
Parents need to be aware of the vision problems associated with computer work.
Computer use demands fine motor skills from young eyes that are not well developed.
According to the American Optometric Association, children have a limited degree of
self-awareness, and may be on the computer for hours with few breaks, resulting in eye
focusing and eye strain.2 Children assume that what they see and how they see is normal
even if their vision is problematic. Since computer workstations are often arranged for an
adult, the viewing angle should be adjusted for children; the computer screen should
angle downward slightly. Also, children may experience neck, shoulder and back pain
due to the difficulty of reaching the keyboard or placing their feet on the floor.
Some tips to follow to prevent Computer Vision Syndrome in children are:
 Workstations should be arranged to suit a child not an adult. The
recommended distance between the monitor and the eye is 18-28 inches
for children.
 Check the lighting for glare on the computer screen.
 Limit the amount of time that a child can continuously use the computer.
A 10 minute break every hour will minimize the development of focusing
problems and eye irritation caused by improper blinking.
 Parents and teachers should be aware of any behavior that indicates
potential problems such as frequent rubbing of the eyes, head turns and
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other unusual postures or complaints of blurriness or eye fatigue.
Avoidance of the computer may also be an indication of discomfort.
Most importantly, every child should have a regular comprehensive eye
exam, including near-point (computer and reading) and distance testing.
The American Optometric Association Clinical Practice Guidelines
recommend children’s eye examinations at the following intervals: at 6
months of age, 3 years of age, before entering school, and every two years
thereafter.
There is no question that computer use has become a way of life. Although CVS has not
been found to cause any permanent damage to the eyes, its painful symptoms can affect
performance at work and at home. As time goes on, computers will continue to be an
integral part of our lifestyle. In order to maintain comfortable, healthy and stress free
vision, regular eye exams and proper computer prescription lenses will insure prolonged
visual comfort.
Bibliography
1. American Optometric Association. http://www.aoa.org/x5374.xml
2. American Optometric Association. Impact of Computer Use on Children's
Vision, June, 1997. http://www.aoa.org/x5379.xml
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any
form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior
written permission of the publisher.
Copyright© 2011 by The American Optometric Association
DON’T LET THEM PUT A STRAIN ON YOU
Test Questions
To receive one hour of continuing education credit, you must be an AOA Associate
member and must answer seven of the 10 questions successfully. This exam is
comprised of multiple-choice questions designed to quiz your level of understanding
of the material covered in the continuing education article, “Don’t Let Them Put a
Strain on You”.
To receive continuing education credit, complete the information below and mail with
your $10 processing fee, $10 per hour of CE before December 31st of this year to the:
AOA Paraoptometric Section, 243 N. Lindbergh Blvd, St. Louis, MO 63141-7881
Name __________________________________ Member ID number _______________
Address_________________________________________________________________
City _____________________________ State _________ ZIP Code ________________
Phone __________________________________________________________________
E-mail Address ___________________________________________________________
Card Type ______________________ Exp. Date _______________________________
Card Holder Name ________________________________________________________
Credit Card Number ____________________________ 3 Digit Security Code _________
Authorized Signature______________________________________________________
Select the option that best answers the question
1. What doe s CVS stand for?
A. Computer Vision Syndrome
B. Computer Vision Symptoms
C. Complete Vision Syndrome
D. Complete Vision Symptoms
2. How many symptoms are needed to diagnose CVS?
A. 1
B. 2
C. 6
D. 3
3. What is the standard reading distance?
A. 14
B. 16
C. 15
D. 20
4. On average, how many hours does a child spend on a computer a day?
A. 3-5
B. 5-7
C. 4-6
D. 1-3
5. What should be parallel to the floor when you type?
A. Legs
B. Shoulders
C. Arms
D. Face
6. CVS has been proven to cause permanent eye damage?
A. True
B. False
7. For every 45 minutes at a computer, how often should an adult take a break?
A. 15-20 minutes
B. 10-15 minutes
C. 30 minutes
D. 5-10 minutes
8. What is the recommended distance for children at the computer?
A 21-27
B. 16-20
C. 18-28
D. 20-25
9. Computer use can result in a decrease of blinking to almost
A. 1/2 of the normal rate
B. 1/3 of the normal rate
C. 1/4 of the normal rate
D. It doesn’t decrease, it increases blinking
10. Binocular Fusion is the
A. Eyes working independently from one another
B. Forming a single image
C. Ability to see things far away
D. Sharpness of vision
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any
form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior
written permission of the publisher.
Copyright© 2011 by The American Optometric Association