Computer vision syndrome: causes, symptoms, and management

Computer Vision Syndrome

According to the Computer Desktop Encyclopedia, Computer Vision Syndrome (CVS) is "A variety of problems related to prolonged viewing of a computer screen. Short-term effects include dry eyes, blurred vision, eye fatigue and excessive tearing. Long-term effects include migraines, cataracts and visual epilepsy. Some solutions are to keep reflections and glare to a minimum and to provide a non-fluorescent, uniform light source. Special lamps are available that maintain the proper light around the monitor and generate light at much higher frequencies than regular light bulbs"

With the ever increasing amount of time consumers are spending in front of their computer screens, this disability is considered on of the fastest growing work related health problems in the country today. For many Americans, the problem cannot be left behind at the office. Individuals come home, to spend time surfing the web, corresponding via email, and pursuing various computer-based entertainment functions. The digital world is swiftly becoming dangerous to the health and well-being of a great many Americans.

Scope of the Problem

According to a recent article in Occupational Hazards, there are more than 70 million personal computers in use in homes and offices across the United States. According to the American Optometric Association, nearly 90% of people who use those PCs for more than three hours a day suffer from eye trouble. In 1999, more than 12 million of them sought eye treatment, at a cost of more than $2 billion a year to health plans. Occurrence of the syndrome has already been measured at an increasing rate. According to MMR Magazine (2001), "... some 60 million or more Americans are said to suffer from computer vision syndrome... And the number is expected to grow, with 21 million children expected to use the Internet at home or in school by next year, suggests Better Vision Institute, a nonprofit organization in Alexandria, Va"

OSHA has also weighed in recently on the issue of CVS. The Occupational Safety and Health Administration recently published its final Ergonomic Program Standard, which identifies that employers must send symptomatic employees suffering from musculoskeletal disorder to an appropriate health-care professional. Under the new standards, CVS has been included as a repetitive stress injury that requires treatment by an optometrist. In other published studies, the American Optometric Association, more than 70% of computer workers suffer from computer vision syndrome.

At the root of all this expense is a familiar cast of discomforts:

Eyestrain (sore or fatigued eyes).

Headache.

Slowness in changing focusing distance.

Blurred vision after close-up work.

Eye irritation (burning, dryness, redness).

Contact lens discomfort.

Sensitivity to light

In addition to problems which prolonged computer use create with users vision, extended computer usage can also affect the posture, and therefore create disabling muscular and skeletal symptoms, including neck, back and shoulder pain. "Computer vision syndrome is the leading health complaint of office workers," says Jeff DeFazio, president and chief operating officer of Cable Car Eyewear.

Workers also are at risk from increased levels of discomfort from glare if they use a dark background display screen on their VDT. The resulting disparity between the dark screen and the glare of overhead lighting create can create ongoing eye strain. Other sources of extreme contrast differences between the VDT and other materials which the user handles at the computer workstation include white paper on the desk, light-colored desk surfaces, desk lamps directed toward the eyes, or desk lamps which illuminate the desk too highly.

Many experts expect CVS to soon surpass carpal tunnel syndrome as the most-common workplace health issue. In accordance with that unwelcome expectation, the insurance industry is warning employers to prepare for a wave of computer-related injury claims: repetitive stress of the eye muscles.

Moreover, the current trend toward doing nearly everything online will likely accelerate the occurrence of CVS. As more people use the Internet at work and at home, the problems of CVS are sure to increase at an accelerating rate. The repercussions could include higher health insurance premiums and HMO fees. CVS is a very real and growing problem for employers and employees.

A host of implications, in the form of lost productivity and absenteeism alone, are compelling affects of the syndrome and are some of the reasons which CVS is drawing so much attention.

According to Chambers (1999) "the Journal of the American Optometric Association cites recent studies by Dr. James Sheedy of the University of California at Berkeley, a principal investigator of CVS. Sheedy's research has shown that minor visual degradations can lower worker productivity from 4% to 19% on common office and work tasks. That could translate into an efficiency drop costing from $1,200 to $5,700 a year for a typical clerical worker with an annual salary of $30,000, or as much as $15,200 a year for an in-demand computer professional with a salary of $80,000. In all cases, the employer takes this "hidden" hit on productivity." recent study at the University of California Berkeley's (UCB) School of Optometry, funded by Viratec Thin Films, Inc. shed new light on what eye care professionals have long suspected, that a leading contributor to Computer Vision Syndrome (CVS) can cause loss of office worker productivity. Specifically, the study focused on the unwanted reflections from a computer monitor that adversely affect the ability of millions of computer users to read information. In reaching this conclusion, UCB researchers studied the effects of various computer display situations on the visual performance, including reading speed, accuracy, comprehension and acuity.

According to the study, subjects reported less glare and fewer CVS-related symptoms with displays that had a vacuum-deposit Optium (tm) coating by Viratec. They were able to perform visual tasks considerably faster and more accurately on these displays than on either uncoated or standard-coated VDT's.

Adding substance to previous anecdotal information, this research is the first to show a direct correlation between glare and reduced productivity," said Dr. James Sheedy, who established the VDT Eye Clinic at UCB's School of Optometry, where the study took place under the direction of Dr. Ian Bailey.

A survey of optometrists recently indicated that out of the 10 million eye examinations are given annually in this country, the majority of them are related to vision problems related to video display terminal (VDT) use. This condition most commonly occurs when the viewing demand of the task exceeds the visual abilities of the VDT user. The American Optometric Association defines CVS as that "complex of eye and vision problems related to near work which are experienced during or related to computer use."

Another aspect of the syndrome is that nearly 80% of our learning comes through the eyes. Therefore any vision difficulties will slow and impede everyday learning and comprehension processes that make for good on-the-job performance. As a result, CVS can become an accelerated problem in the business world. As a result the condition is being approached as a serious disorder with real, and financial bottom-line consequences for business.

Looking at the changing nature of the classroom, CVS could pose an upcoming threat for students at all levels of education. Because the internet is being used increasingly for school projects, and word processing tasks, today's students are being exposed to VDT at levels which today's working adults did not experience. The body of research on CVT has not been accumulated sufficiently enough to project what could be the result of increased computer usage at early ages, and whether or not the symptoms of CVT are cumulative. However, if early usage adversely affects the users ability to use computers, when today's students reach working age, the problems could cascade into significant obstacles to worker productivity.

The Physiological process which creates the syndrome

At home or at work, computers have become an integral part of our lives, and we use them more and more to accomplish personal and job-related tasks. They usually make things simpler (until the inevitable data crash). As a result, we have to spend more time in front of CRT screens watching pixels and electrons, and being subjected to higher amounts of CRT radiation. As a child, parents often told their children to not sit too close to the television because it could disrupt / damage their vision. Warning labels on microwave ovens instruct the users to remain a safe distance from the appliance while in use, due to the electromagnetic fields which are generated. However, in regard to the computer screen, we are limited to the length of our arms. As a result the muscles, tissues and nerve cells in our eyes must work harder, and are subjected to higher levels of electromagnetic fields.

While viewing a computer screen, our eyes must continually refocus in order to adjust to changing information on the screen. This process of continuous adjustment is unnatural for the human optical system. In a typical office, workers also routinely switch attention back and forth between the close-up screen and paper documents or publications on our desks, etc. The back and forth, near to far refocusing also places even more stress on the eyes. The continual refocusing sets off a chain of effects that ultimately leads to CVS:

While using a computer, the average person blinks about four to six times per minute. The normal rate is 22 blinks per minute that keeps eyes naturally moistened.

Reduced blinking leads to a "dry eye" condition caused by excessive evaporation of eye moisture. The condition devolves into itching, burning, blurring, heavy eyelids, fatigue and even double vision.

When "dry eye" sets in, most people tend to arch their eyebrows upward to continue seeing clearly. This can eventually cause a headache.

As a result, in order to fend off the dry eyes and headaches, people unconsciously resort to uncomfortable and awkward postures in front of their PCs. From these advancing and repetitious gyrating, CVS is associated with "baffling" musculoskeletal problems such as back pain, neck stiffness and sore shoulders.

Remedies and Personal Adjustments

Ergonomic

Because researchers have come to understand the physiological dynamics of CVS they have defined some ergonomic countermeasures. While these suggestions do not eliminate the problem entirely, they can alleviate some of the symptoms by disrupting the processes that led to them.

Placing computer screens slightly below eye level

Situating seats and desks to keep 20 to 26 inches between employees and their screens. While this is the natural focusing distance for eyes, this cannot be attained for laptop users.

Arranging reference material close to monitors and at the same level to reduce the amount of continual refocusing.

Advising employees to keep PC monitor contrast and brightness at lower levels

Installing glare screens on monitors.

Introducing appropriately placed lighting that does not cause random reflections on screens.

Office ergonomics are proving to be an effective defense against CVS, but the sheer prevalence of computer-oriented jobs, combined with ever more time spent in front of the screens, often makes it necessary to provide specifically designed protection for heavy-duty PC users.

Personal Protection at Eye Level

CVS creates special needs for people who wear prescription eyeglasses or contact lenses. Most prescription lenses are designed to help people read print, but they are not specifically designed for computer work. Bifocals also complicate matters by forcing wearers to look at the screen through the bottom of the lenses, causing additional ergonomic challenges as they crane their necks to the point of backache. So eyeglass wearers should consider getting an extra pair of eyeglasses designed for the right kind of focusing.

Prescription eyeglass wearers have had an additional resource available to them to fight advantage against CVS over the past few years. Their optometrists could prescribe lenses with special color filters that counteract the effects of CVS by screening certain light wavelengths, radiation, and electromagnetic fields which come from computer screens. Progressive employers who utilize a high number of computers in their offices have been quick to see the benefits of this filtering technology, and many cover the costs of eye examinations and these glasses to make sure employees can do their work without problems. Uvex Safety had become one of the first producers of protective eyewear for the workplace, and they have been among the first to offer this option to employer. The company recently introduced a family of nonprescription eyewear called "PCvision, which uses a new variant of filtering called enhanced visual amplification (EVA) lens technology."

Another company is Cable Car Eyewear, which offers its I-Optix Computer Eyewear collection, which uses a "patent-pending lens technology to reduce the glare from ambient light sources while increasing the crispness of screen contrast and eliminating color distortion." The I-Optix line includes several Computer Readers eye glasses for people who wear reading glasses while using a computer. Cable Car's I-Optix Computer Glasses are non-magnifying to accommodate people who do not need corrective vision eyewear.

Reducing Glare

Taming glare is the second approach which a company can take in order to reduce the likelihood of CVS amongst its employees. Many of these solutions are low to no cost, and they can significantly reduce the likely hood of CVS.

Situate the computer so the screen is perpendicular to windows and not directly below overhead light sources.

Use a glare screen

Use a flat-screen monitor, not one with convex screen.

Avoid using light-colored backgrounds or patterns on the screen, and stick with dark characters on a white field.

Clean the monitor and glare screen regularly

Have a complete eye exam by a qualified professional at least every two years.

If you experience pain, flashes of light, floaters, blind spots, or blurred vision, make an appointment immediately.

When you buy eyeglasses, tell your optometrist about your computer use patterns.

Position task lighting so it illuminates the document, not your computer screen. If you can see the light reflected when you look at the screen, move the light farther back or to a different angle to the screen.

Nutrition

Just as an athlete in training has different nutritional needs than the person who works in an office, the person who sits behind a VDT for many hours each day has increasing levels of nutritional demands on the tissues, muscles and nerves in his or her eyes. Recent research has identified a small collection of nutrients which are essential to eye health. Proper eye nutrition can even reverse degenerative eye diseases. In order to ward off the onset of CVS, nutrition can be used as a preventative measure.