Review Article
Computer vision syndrome
Alam AKMS
The ORION Medical Journal 2009 Sep;32(3):692-693
Definition
According to the American Optometry
Association, Computer Vision Syndrome
(CVS) is the complex of eye and vision
problems related to near work which are
experienced during or related to computer
use. CVS is characterized by visual symptoms
which result from interaction with a computer
display or its environment. In Most cases,
symptoms occur because the visual demands
of the task exceed the visual abilities of the
individual to comfortably perform the task. If
these symptoms occur without significant
usage of computer they cannot be termed as
CVS.
Introduction
The revolutionary technological advancement
has made an impact in almost every aspect of
our lives. Our daily tasks, office works,
medical facilities, accounting, designing,
database management and experimental
works have all been greatly facilitated by this
rapid pace of development in computer
technology. The personal computer (P.C) thus
becomes a single device which has made a
great revolution in all aspect of our lives.
Approximately 100 million people in the
world are using computers now. In USA 71%
of children work with computer in school. In
India about 20 million PCs are in use. In our
country the use of computer is increasing day
by day. The cost of diagnosis and treatment of
CVS in USA alone exceeds 2 billion annually
which indicates a reflection of importance to
think about this new emerging medical and
visual problem.
Pathophysiology
CVS is contributed by several factors:
1. Decreased blinking reflex: Studies have
shown that the normal blink rate in human
1. Dr. A.K.M. Shariful Alam, DO (DU), MS
(Ophthalmology), Registrar, Department of
Ophthalmology, S.S.M.C. Mitford Hospital, Dhaka
The ORION. Vol 32, Issue 3, September 2009
eyes is 16-20 blinks/min. For persons
working on the computer it is decreased to 68 blinks/minute. This leads to dry eyes.
2. Prolonged near focusing efforts: Puts strain
on ciliary muscles of the eye and leads to a
feeling of tiredness in the eyes. This can be a
setting for early presbyopia.
3. Repeated head posture change/fixation in a
wrong posture: Puts strain on the neck
muscles and cervical spine.
Symptoms
Eyestrain (non-specific ocular discomfort),
fatigues, headache, blurred near vision,
blurred distant vision, dry or irritated eyes,
neck pain and/or backaches, diplopia (double
vision), difficulty in re-focusing the eyes.
Visual/ocular signs
Accommodative disorders, early presbyopia,
binocular vision dysfunctions, refractive
errors: hyperopia, astigmatism, myopia, dry
eyes, conjunctival congestion (redness).
CVS associated musculo-skeletal disorders,
Cumulative Trauma Disorder (CTD) or
Repetitive Strain Injury (RSl): Carpal Tunnel
Syndrome, bursitis, neck tension syndrome
(muscle strain), tendon disorders- De
quervain's disease, tenosynovitis- trigger
finger.
Environmental factors of computer
workstations
Contrast and resolution of the display,
viewing distances and angles, adjustability of
workstation, room lighting, sustained
viewing.
Relationship of CVS to RSl or CTD
(Musculoskeletal disorders)
Symptoms are work related and associated
with repetitive activity. Problems are related
to disorders of muscles, tendons, bones, or
nerves. Problems occur or are aggravated by
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repeated movements. A lengthy period of
time is required for the problems to develop
and for the individual to recover.
Diagnostic tests
Tear film Break-up time (TF-BUT):
Examined under slit-lamp with a red free
light. Fluorescein dye is used. Normal->10
seconds.
Schirmer Test-1: Special graduated paper
strip is used. Normal value- >10mm in 5
minutes.
Rose Bengal Staining: To detect corneal and
conjunctival epithelial defect in dry eyes. A
positive result is highly significant for CVS.
Management
Proper History
Symptoms, duration, aggravating and
relieving factors. Nature of work, computer
exposure time. Existing workstation setting,
furniture, lighting, etc. Per-existing ocular or
musculoskeletal diseases. Examinations.
Refractive status-near, intermediate and
distant. Ocular motility, Versions and
Vergence. Thorough neuromuscular work-up.
Differential diagnosis
1. Cervical spondylitis
2. Migraine
3. Anxiety Neurosis
4. Dry Eye Syndrome
Investigations
1. X-ray of cervical and lumbo-sacral spine
for exclusion of pre-existing spinal disease
2. TF-BUT, Schirmer-1
3. Rose Bengal test
Treatment
A. Counseling regarding
1. Awareness building
2. Work environmental modification
B. Computer eyewear
C. Tear substitute
A. Counseling: 10
computer eye strain:
steps
for
relieving
The ORION. Vol 32, Issue 3, September 2009
1. Get a computerized eye exam before start
using computer. Repeat once a year.
2. Use proper lighting. Eliminate exterior
light by closing drapes, shades or blinds.
Reduce interior lighting by using lower
intensity bulbs and tubes.
3. Minimize glare: To install an anti-glare
screen on your monitor. Paint bright white
walls a darker color with a matte finish.
4. Upgrade your display. Use LCD monitor
instead of a CRT monitor.
5. Adjust the brightness and contrast of your
computer screen.
- The brightness of the screen should be the
same as the work environment. Contrast
between screen background and on- screen
characters should be high.
- The text size and color should be optimized
for the most comfort.
6. Blink more often.
- Every 20 minutes, blink 10 times by closing
your eyes as if falling asleep (very slowly).
7. Exercise your eyes: Follow 20-20-20 rule
i.e after every 20 minutes, look at 20 feet
distance for 20 seconds.
8. Take frequent breaks- two 15-minute
breaks -four additional five-minute "minibreaks" throughout the work day (6-8 hrs).
9. Modify your workstation.
- Proper posture during computer work.
Ergonomic furniture. Position computer
screen 20 to 24 inches from your eyes. The
center of your screen should be about 10 to 15
degrees below your eyes. Top of the screen
tilted back slightly (10-20 degree) away from
the operator.
10. Consider computer eyewear and avoid
contact lens use during computer work.
B. Computer eyewear
Customized eyeglasses specific for use during
work on a computer screen. Anti-reflective
coating in the lenses should be used.
PresbyopiaSingle
vision
lenses.
Intermediate/near bifocals. Special multifocal
lenses. Computer Eyewear should also be
considered if a person have CVS related
symptoms in: Latent hypermetropia, Low
astigmatism, Heterophoria, Convergence
insufficiency, Disorders of accommodation
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before 40. Person may not require spectacle
correction for general vision needs.
C. Tear Substitute
Considered if 1. Symptoms occur/aggravated
during computer work. 2. TF-BUT- <10
seconds. 3. Schimer-1- < 10 mm in 5
minutes. 4. Rose Bengal Test- Positive.
Commercially available Tear SubstitutesSodium Carboxymethyle Cellulose. Povidon
Solution, Dextran 70
solution 2%,
Hydroxypropyl
Methyle
Cellulose
(Hypromellose) 0.5% etc.
Children and computer vision syndrome
The average American child now spends 1 to
3 hours per day on the computer. 90% of
school age children have computer access at
home or in school. 54 million children in the
United States alone use a computer at home
or in school. 25% to 30% of computer user
children need corrective eyewear. A study in
Singapore found that in 3 years the
percentage of 7 to 9 years old with myopia
had doubled, to 34%.
Twenty years ago, most children
played outside, and their distant vision
was more important.
Today it is a "Near Point World". In
Bangladesh also, Specially, in upper
middle and upper class, children spend
on an average 1-3 hrs in front of a
computer/video display terminal.
Children have a limited degree of self
awareness.
Children
are
very
adaptable. Obviously the size of the
children are smaller than adults.
Five tips for preventing computer vision
syndrome in children
1. Before starting school, every child should
have a comprehensive eye exam, including
near point (computer and reading) and
distance testing.
2. Workstations should be arranged to suit a
child-not an adult.
3. The recommended distance between the
monitor and the eye for children is 18-28
inches.
The ORION. Vol 32, Issue 3, September 2009
4. Any behavior that indicates potential
problems: Parents and teachers should be
aware of eye redness. Frequent rubbing of the
eyes. Head turns and other unusual postures,
or complaints of blurriness or eye fatigue,
avoidance of the computer.
5. Most importantly, have your child's eyes
examined by a computer vision specialist.
Conclusion
In this computer era there is no scope to avoid
this modern technology rather its use is
expanding everyday in the perspective of
digital Bangladesh along with global
digitalization. If we can make awareness
among the computer users regarding its
proper uses in respect of optimum amount of
work time, proper setup & work positions,
related health & eye problems which may
occur and some training and tips to the users
to solve the common problems can be
provided, at least 50% of the computer vision
syndrome & closely related problems will be
minimized. Rest of the problems which may
be more specific & individualized need close
co-operation between computer users and
expert, trained ophthalmologist so that
maximum work can be done with comfort
with or without minimum discomfort. Here
another point should be kept in the mind of
the guardians of the children who are very
much habituated to work on a video display
terminal for hours together for their any
behavioral change, ocular complaints,
headache, even visual defects which may be
ignored by the children easily for their more
adaptiveness. But the parents should be very
consious to identify their problems and should
take proper measure by consulting with the
computer vision syndrome specialists for the
prevention of permanent disabilities.
References
1. Highlights of Ophthalmology Vol: 35 N: 42007 P: 24-28
2. Computer Vision Syndrome, Zaktadu
Okulistyki Centrum Naukowego Medycymy
Kolejowej, Warszawie. PMID: 8090002
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3. Negative impact of video display terminals
on the organs of vision. Kim In, Megeda EVRussia.
4. Computer vision syndrome: a review
Blehm C, et. Al, Dept. of Oph. and Visual
The ORION. Vol 32, Issue 3, September 2009
Sciences, University of Texas, Houston,
Texas, USA.
5. Factors leading to the Computer Vision
Syndrome: an issue at the contemporary
workplace. Izquierdo JC, et. Al. Academia
Perpetuo socorro, Miramar, Puerto Rico.
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