Most eye care professionals agree that computer users demonstrate unique eye and vision problems. The sources for these problems relate to both
the visual ergonomics of the work environment and individual visual disorders. If we assume that as many as 70 million people in the United
States use a computer for work and/or entertainment at night, the development of the worldwide web and increase in globalization of the
workplace will increase the number and frequency of visual problems exponentially. Therefore it is important, from both a medical and an
industry point of view, to act preemptively to curtail these visual disorders (and related secondary muscular skeletal disorders) to prevent
an increase in visual disorders as well as both employee injury and lower employee productivity.
Visual symptoms begin when the visual demands exceed the visual capabilities of the individual. Most people have marginal visual disorders such
as a refractive error, poor accommodation, or strabismus, and are usually able to adapt and cope with these minor imperfections of the visual
system in their daily lives. When they cannot, they often wear glasses to correct refractive error, use prism within the lens, and their
built-in fusional amplitudes to control our muscle weakness to allow better vision.
Computer users on the other hand confront difficult challengers. First, computer user must have excellent vision. The computer monitor
(Video Display) screen is usually about 20 to 22 inches from the eyes. If the screen is viewed with uncorrected vision, studies have
demonstrated a 4% to 19% decline in visual task performance. Over an eight-hour workday, this would translate to as much as a 90-minute
loss of employee productivity, and a 20 to 25% increase in employee fatigue.
Factoring in the demographics of an aging America (for example, an over-40 user with bifocals), we see an increased probability of stress
from arching the neck to rid the computer screen of the annoying bifocal line. Elevating and depressing the neck leads to unavoidable
excess accommodation, and will induce unnecessary neck and back strain. Over time, the repeated exertional movements of the neck and spine
develop into muscular-skeletal disorders. Some muscular-skeletal disorders can continue to be aggravated by completed exertions and movements,
and in extreme cases lead to disability of the employee and unable recovery.
Secondly, computer users must have perfect binocular vision and accommodation. The use of a computer monitor demands that users converge their
eyes to a single sentence or object 20 to 22 inches away. Studies in the general population have shown a 20 to 25% incidence of
convergence disorders, including convergence insufficiency and convergence excess. Any vertical phorias or horizontal exophorias would need to
be corrected to ease the eyestrain or asthenopia. Reading glasses with increased magnification lenses would improve convergence excess,
and convergence insufficiency would need to be treated with base and prism and visual therapy.
Thirdly, computer users would have to have excellent accommodative response. They would have to be able to accommodate on the keyboard and
then look up at the screen, etc. Allowance for accommodation of these different distances should require wide range with the increased age in
the workforce, and this will be an increasing source of the asthenopic problems and blurred vision.
Finally, computer users who wear contact lenses also confront severe demands. A normal blink rate of 10 to 12 times per minute decreases as
one visualizes the computer monitor down to a rate of 6 to 8 times per second. This decrease in blink rate is often associated with arid
office environments, and further compounds the dryness and may lead to clinically significant tear deficient eyes. The unusual angle of
the computer monitor may additionally impose demands that require the user to open the eye wider in order to to completely see the screen.
This practice worsens the clinical situation to the point where the employee may need to use medication to wet their eyes and improve their
blurred vision and symptomatology. The use of artificial tears, lubricating tears, tear plugs, and tear stimulating drugs would impose a cost
of millions of dollars upon the employee workplace, and also lead to diminished employee productivity.
What can medical and industry professionals do to improve the office environment and to reduce computer-related visual symptoms and
muscular skeletal disorders? Eye care professionals must fit these patents with appropriate frames and spectacle lenses accurately. Single
vision and bifocal lenses may be necessary options. Progressive lenses may also be needed to relieve annoying bifocal line and eliminate
postural deformity. In addition, eye care professionals must diagnose the strabismus disorders such as convergence excess and
convergence insufficiency, and treat these with additional glasses and visual exercises. Prism may be needed to control some of the
vertical phorias or atrophies.
The computer industry must also improve the ergonomics of the computer workstation. The industry must work to eliminate the fatigue and the
accuracy of accommodation and convergence of the eyes.
IMI Innovations, Inc. has taken a preemptive role to eliminate visual disorders. The use of two independent Mice prevents continued adjustments
in accommodations as individuals go from keyboard to screen, and also between different areas of the screen. If computer users do not
continually adjust convergence (at a rate of several times a minute) the muscles don’t tire and further fatigue can be avoided.
Furthermore, looking at the center of the screen and using both mice to navigate and then implement avoids continued movements in all
different directions, requiring fusional and torsional adjustments when they return to fixation again.
In conclusion, computer users represent a large and growing segment of the population. We must act responsibly to reduce the incidence of
visual and muscular skeletal disorders that appear to be growing at an increasing rate. Eye care professionals must control the inherent
visual imperfections in the computer users visual system.
The computer industry must act to improve the ergonomics of computer use. IMI Innovations, Inc. is a company that appears proactive in this regard.
Gregory A. Stainer, M.D., F.A.C.S.
Dr. Stainer has been in private practice in Bakersfield since 1981. He began his medical career at Northwestern University in Chicago, where
he completed his internship at Northwestern Hospital and his residency at the University of Wisconsin. He completed his fellowship training
for Corneal & External Diseases at the University of California, San Diego. He has traveled extensively throughout the United States to
participate in the study of Laser Vision Correction through the use of the Excimer Laser to correct nearsightedness and astigmatism. In
addition, Dr. Stainer has extensive experience with multiple types of lasers for aesthetic and reconstructive surgery.
THE EYE & THE COMPUTER INTERFACE
By Gregory A. Stainer, M.D., F.A.C.S.
Millennium Surgical center, Bakersfield, CA
