Computer Vision Syndrome

Written by :

Atika Prissilia

030.07.038

Medical Faculty of Trisakti University

Jakarta

2011

ABSTRACT

As computers become part of our everyday life, more and more people are

experiencing a variety of ocular symptoms related to computer use. These include eyestrain,

tired eyes, irritation, redness, blurred vision, and double vision, collectively referred to as

computer vision syndrome. The effect of CVS to the body such as back and shoulder pain,

wrist problem. Computer vision syndrome symptoms may be the cause of ocular (ocular-

surface abnormalities or accommodative spasms) and/or extraocular (ergonomic) etiologies.

However, the major contributor to computer vision syndrome symptoms by far appears to be

dry eye. The visual effects of various display characteristics such as lighting, glare, display

quality, refresh rates, and radiation are also discussed. Treatment requires a multidirectional

approach combining ocular therapy with adjustment of the workstation. Proper lighting, anti-

glare filters, ergonomic positioning of computer monitor and regular work breaks may help

improve visual comfort. Lubricating eye drops and special computer glasses help relieve

ocular surface-related symptoms. More work needs to be done to specifically define the

processes that cause computer vision syndrome and to develop and improve effective

treatments that successfully address these causes.

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INTRODUCTION

Computers are one of the most fascinating inventions of the 20th century. However,

computer users confront new challenges both at their workplace and school systems. By

working long hours using a computer monitor, a compilation of systemic and ocular

symptoms may develop.

Vision is our most precious sense. Our eyes are in constant use every waking minute

of every day. The way we use our eyes can determine how well we work throughout our

lifetime. Over 80% of our learning is mediated through our eyes, indicating the important role

our vision plays in our daily activities. Vision disturbance is a silent enemy that only appears

after along period of continued stress.

Because computer use is such a high visually demanding task, vision problems and

symptoms have become very common in today’s workplace. Most studies indicate that

computer operators, who view their Video Display Terminals (VDTs), report more eye-

related problems than non-VDT office workers. A number of investigators have indicated

that visual symptoms occur in 75-90% of VDT workers.

The causes for these visual symptoms are a combination of individual visual

problems, poor workplace conditions and improper work habits. So, how good we could

prevent those problems is definitely the main key to reduce the risk of CVS. By then, the

prevalence of CVS will decrease and the worker’s productivity will increase.

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DISCUSSION

I. Definition

Computer vision syndrome (CVS) is a temporary condition resulting from focusing the

eyes on a computer display for protracted, uninterrupted periods of time. Some symptoms of

CVS include headaches, blurred vision, neck pain, fatigue, eye strain, dry, irritated eyes, and

difficulty refocusing the eyes. These symptoms can be further aggravated by improper

lighting conditions or air moving past the eyes  (e.g. overhead vents, direct air from a fan).

II. Prevalence

A large percentage of computer users have eye symptoms and, thus, seek eye

examinations. According to Thompson, the prevalence of ocular symptoms in computer

users, as part of the computer vision syndrome, ranges from 25-93%.

Studies by Sheedy and coworkers suggest that 1 out of 6 patients requiring eye

examinations have a computer-related eye problem. The cost of eye care examinations and

glasses made for computer users is a nearly $2 billion industry, although these costs are

certainly not all directly a result of the computer vision syndrome.

III. Comorbidities

Some researches reported that approximately 22% of computer workers have

musculoskeletal problems, such as neck problems, back problems, shoulder problems, and/ or

carpal tunnel syndrome.

IV. Etiology

The etiology of computer vision syndrome (CVS) is multifactorial. Several issues may

lead computer users to this syndrome. These factors may be environmental, personal, or a

combination of both.

A. Computer user :

Not ergonomic body position

Causes musculoskeletal disorders such as wrist problems, bursitis, muscle strains,

tendon disorders and tenosynovitis. These disorders are generally classified as

Cumulative Trauma Disorders (CTD) or as Repetitive Strain Injuries (RSI).

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Eye disorder such as strabismus, refraction disorder, incuficient of

accommodation.

B. Computer :

Screen

Computer screen are created by combinations of tiny points of light (pixels), which

are brightest at the center and diminish in intensity toward their edges. This makes it more

difficult for our eyes to maintain focus on these images.

Keyboard

Keyboard position that not appropriate can cause repetitive strain injury of wrist, like

carpat tunnel syndrome. The symptom will appear such as pain in the wrist or we can not

extension the fourth and fifth digits.

Chair

Chair positon has crucial role for musculoskeletal pain, such as lower back pain.

Comfort chair position will help the computer user to reduce the risk of lower back pain.

C. Room :

Lighting

Light reflected from the lamp or window which direct to the eye will reduce

capability of eye to get shadow focus.

Air conditioner / fan

Air conditioner which direct to the eye will increase evaporation of humor aqueos, so

it can be a causes of dry eye syndrome.

V. Signs and Symptoms

Employees suffering from CVS experience such as :

- Headaches

- Eyestrain

- Itchy eyes

- Tired eyes (asthenopia)

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- Blurred vision

- Double vision

- Fatigue

- and Tense muscles (e.g neck and shoulder pain)

Extreme CVS can even cause :

- Nausea

- Poor nutrition and loss of appetite

- Migraines

- and Cluster headaches

The prolonged computer use can also cause a tightening of facial muscles around the

cheeks, temples, and nose. This facial tightening leads to reduced blood circulation,

compounding the effects of eye fatigue.

Parents should be aware of how long their child spends on the computer at one time.

Children often do not mention such symptoms as blurred vision caused

by nearsightedness, farsightedness, or astigmatism because they think everyone sees the

way they do. Uncorrected farsightedness can cause eyestrain at the computer because

the eyes must work hard at focusing on a near object for an extended period of time.

Every child over the age of 4 should have a comprehensive eye exam to be sure that

vision problems are diagnosed and corrected. This is particularly important because

children now spend so much time in front of a computer.

VI. Pathofisiology

CVS is caused by decreased blinking reflex while working long hours focusing on

computer screens. The normal blink rate in human eyes is 16–20 per minute. Studies have

shown that the blink rate decreases to as low as 6–8 blinks/minute for persons working on the

computer screen. This leads to dry eyes. Also, the near focusing effort required for such long

hours puts strain on ciliary muscles of the eye. This induces symptoms of asthenopia and

leads to a feeling of tiredness in the eyes after long hours of work. Some patients present with

inability to properly focus on near objects after a short duration. This can be seen in people

aged around 30–40 years of age, leading to a decrease in the accommodative focusing

mechanisms of the eye. This can be a setting for early presbyopia.

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VII. Clinical

History

The patient's history should be obtained, including age, chief complaint, and onset of

symptoms.

In obtaining a history of present illness, the ocular symptoms should be evaluated.

Patients with computer vision syndrome (CVS) complain of several symptoms, such

as blurred vision, dryness, burning sensation, stinging, red eyes, tearing, and

photophobia.

Previous eyeglasses prescriptions and eye medications, including lubricants, should

be evaluated.

The review of systems may include such issues as xerostomia, thyroid

disease, menopause, arthritis,carpal tunnel syndrome, Parkinson disease, and systemic

medication use that may exacerbate dry eye symptoms (eg, anticholinergics,

antihistamines, antidepressants, diuretics).

Environmental factors, such as computer setup, seating, wrist position, monitor type

(cathode ray tube vs plasma), desktop color, window proximity, and ceiling and desk

illumination sources, should be evaluated.

Physical

Patients with CVS should undergo a comprehensive ophthalmic evaluation that includes the

following:

Best-corrected visual acuity for near, intermediate, and distance vision

Manifest refraction at near, intermediate, and distance for refractive errors - Computer

users may have refractive errors, including presbyopia.

A slit lamp examination to evaluate tear meniscus and corneal staining

o Patients with this syndrome may have superficial punctate keratitis.

o The lens should be evaluated for cataract formation.

Intraocular pressure should be evaluated.

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A fundus examination to evaluate the optic nerve, vessels, macula, and peripheral

retina

A cycloplegic refraction is of utmost importance because young computer users with

this syndrome may have refractive errors, particularly latent hyperopia, that may lead

to visual symptoms.

A Schirmer test to evaluate for dry eye

The general physical features in patients with CVS include neck muscle spasms.

The general environmental evaluation in patients with CVS includes the following:

Angle of gaze

o Previous studies suggest that the angle of gaze is the most important risk

factor that leads computer users to develop CVS. For this reason, it is of

utmost importance to estimate the angle of gaze needed to look at the

computer's monitor. For the purpose of this discussion, the center of the

monitor will be used as a reference point to measure distances both from the

floor and from the lateral canthal area, as shown in the image below.

o

Angle of gaze.

o To calculate the angle of gaze that a patient uses at the workstation, the

ophthalmologist may measure or ask the patient to measure the following:

The distance from the computer user's body to the center of the

monitor (labeled as A)

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The distance from the floor to the center of the computer monitor

(labeled as B)

The distance from the floor to the lateral canthal area of the patient's

eye (labeled as C)

o The absolute value of the difference between the distance from the floor to the

center of the computer's monitor (labeled as B) and the distance from the floor

to the lateral canthal region of the computer user's eye (labeled as C) is

calculated and labeled as D. In other words, ([B - C]) equals (D).

o Using this information, the angle of gaze that a patient uses to look at the

center of the monitor is calculated using the following formula:

Angle of gaze = tan-1 (D/A)

Estimate room humidity.

Evaluate room luminance.

VIII. Therapy and Prevention

Therapy for computer vision syndrome is depend on causes. But, sometimes we can

treat the symptoms and intervensive the risk factor.

a) Therapy for symptom

Dry eye

Dry eye is a major symptom that is targeted in the therapy of CVS. The use of

over the counter artificial tear solutions can reduce the effects of dry eye in CVS.

Asthenopia or eye strain

We can do some massage around the eyebrow, close the eye for 3 until 5 seconds

each 15 minutes after two hours of continuous computer use. Also, for every 20

minutes of computer time, look into the distance for 20 seconds -- the "20/20" rule.

b) Intervensive the risk factor

Ergonomic body position

Body position has contribution to prevent computer vision syndrome. The angle of

the eyes to computer screen arrange 20 degrees, it will reduce the risk for asthenopia.

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And then, the arm position to keyboard, leg position to chair, whole body position to

chair and computer table will affect the good ergonomic position.

Optimally, the computer monitor should be 20 to 30 degrees below eye level

(about 5 or 6 inches) as measured from the center for the screen, and 20 to 28 inches

from the eyes.

Good lighting

Light reflected from the lamp must be indirect, it means for reduce unsuitable

light that cause photophobic. The ideal window position is from the side of the

computer, it porpose to make the screen not be impacted light from the window.

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Glare screens

Anti-glare filters for computer screens may increase comfort somewhat, but they

will not solve all your computer vision problems. These filters only reduce glare from

reflections on the computer screen and do not reduce the visual problems related to

the constant refocusing of your eyes when you work at a computer.

Computer eyeglasses

Wearing specially prescribed computer glasses while working at your computer

may keep your eyes from getting worse by reducing excessive focusing demand on

your eyes.

Lenses for computer glasses

The best type of lenses for computer glasses usually depends on your age. If you

are in your 40’s or older, it is likely you have some degree of presbyopia. If so,

multifocal lenses will usually be your best choice because they provide better depth of

focus than single vision lenses. This will let you see your computer screen clearly and

also see objects that are closer and farther away than your screen. Single vision lenses

can also be a good solution for computer glasses, though your depth of focus will be

more limited with these lenses if you are presbyopic. Your eye doctor will help you

decide whether multifocal or single vision lenses are the best solution for your work

environment and your visual needs.

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IX. Treatment

Medication

Medical therapy for dry eye symptoms as part of this syndrome includes the following:

Topical lubricants

Cyclosporine A ophthalmic emulsion

Punctal occlusion

Surgical Care

Surgical indications used for patients with dry eye syndrome are also used for patients

with CVS. Some patients may benefit from punctal plug insertion.

X. Complication

Complications in patients with CVS are similar to those in patients with dry eye,

including superficial punctate keratitis and keratitis.

Watch for optical decentration in eyeglasses by examining the patient's pupillary

distance (PD). Consider using monocular PD measurements as needed. The patient's PD

should be compared to the PD found in prescribed eyeglasses. Consider advising the

optician on the patient's dominant eye.

Watch for bifocal height malpositioning in eyeglasses. Consider advising the optician on

the patient's dominant eye.

XI. Prognosis

Early evaluation, diagnosis, and intervention may prevent the symptoms associated with

CVS. Symptoms associated with this syndrome may be improved with lubricants.

CONCLUSION

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Computer vision syndrome (CVS) occur when we use computer for long times. The

symptom will affect all of the body and it also affect productivity to work. There are many

methods to prevent and treat CVS, such as change of habbit when using computer or

intervensive the instrument of computer and the environment where we work.

REFERENCES

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1. Dry Eye Syndrome.

Available at: http://www.nlm.nih.gov/medlineplus/dry-eyes therapy.html

Accessed May 25, 2010.

2. Informa Health Care. Study for Computer Vision Syndrome. May 2007, Vol. 8 (7):

Pages 211-20.

Available at: http://informahealthcare.com/doi/stud/10.1517/14656566.8.7.211

Accessed May 30, 2010.

3. Mayo Clinic Staff. Computer Vision Syndrome.

Available at: http://www.mayoclinic.com/health/CVS/DS0031

Accessed May 25, 2010.

4. Medicinet. Musculoskeletal disoredered.

Available at: http://www.medicinenet.com/MSherapy/article.htm

Accessed May 30, 2010.

5. National Library of Eye diseases.

Available at: http://www.nlm.nih.gov/medlineplus/Eyestrain.html

Accessed May 25, 2010.

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