Edition No. 13

What are Computers Doing to Our Eyes and How Do We Protect Them?

By Dr. John Bonsett-Veal, OD
and Shari Falkenburg, MS, OTR, CPE

Today’s computer users, whether they’re in elementary school or part of a vast electronically dependent workforce, face the scary prospect of a double edged vision sword: the persistent march of time coupled with the detrimental effects of staring at their monitor screens for a good part of their waking hours.

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The aging process brings common visual problems—greater difficulty seeing without higher levels of luminance, as less light reaches the retina; slowing of the eye’s abilities with more eye strain and fatigue; greater susceptibility to glare; loss of near vision (ability to focus on close objects); need for greater contrast; and diminished color perception.

By 2020, the incident rate for cataracts is anticipated to affect 30.1 million Americans. According to the Archives of Ophthalmology, age-related vision problems will continue for 77 million baby boomers beyond retirement age.
Our ability to work productively depends on our visual capacity, which decreases with age, starting at 25 to 30 years. This, compounded by daily exposure to computer screens by workers in almost every type of business, big or small, should be an alarming cause for concern.

In fact, in a 2004 survey, The American Optometric Association found that 61% of computer users (1,000 people surveyed) are concerned about potential vision problems. Aside from the health concerns of workers, employers also need to take into consideration that even a small amount of uncorrected visual problems leads to reduced visual task performance and productivity, estimated to be as much as 19%.

The US Census Bureau states that half of all adults use computers in their workplace, that three-quarters of all school age children use computers and that half of us have computers at home. Clearly, aging eyes and the development of eye problems, including Computer Vision Syndrome (CVS), should be a concern not only for computer users, but for employers who have employees working more than two hours each day at computer terminals—computer programmers, graphic artists, writers, insurance adjusters, call center employees, flight controllers, secretaries, business executives, etc.

CVS is a condition marked by symptoms such as sore, dry, irritated eyes, fatigue, headaches, blurred or double vision, neck pain or muscle spasms. (Note: OSHA recognizes CVS as a recordable injury and that optometrists are the selected medical providers to conduct computer eye exams.) Correcting potential vision problems and workstation visual conditions is easier than you may think and can ward off this type of injury.

The Visual Process

Aging eyes compound the challenges of the visual system. Presbyopia creates a loss of the eye’s natural elasticity to focus (its accommodation system), creating a need for reading glasses or bifocals. The ability to tolerate mis-correction of vision diminishes with age. Additionally, the quality and quantity of the corneal tear film diminishes over time, and this can lead to significant ocular health issues if the blink rate is decreased during certain activities. Since the blink rate reduces up to four times with computer use, this is of particular concern for computer users and their employers.

Any mis-correction, when combined with other vision stressors, can cause significant eye pain and headaches, along with an irritable mental state. Other health issues can develop in computer use, including asthenopia, dry eye syndrome or general physical fatigue. Left undiagnosed and untreated, these can form together to create eye problems including CVS.

Work Station Evaluation

Conventional workstation evaluation looks for well-designed seating to provide stable body support and allow movement and comfort of the extremities.

Traditional ergonomic assessment consists of: thighs positioned approximately in a horizontal position and the lower legs vertical; the seat height at or slightly below the popliteal height (i.e. knee) of the user (while feet are resting on the floor or a footrest); upper arms hanging vertically, with the forearms horizontal and elbows close to the body; minimal bending of the wrists; an erect spine/upright posture, with the proper pelvic tilt; the soles of the feet making an angle of 90 degrees with the lower legs; minimal twisting or leaning of the torso.

All this may help reduce eye strain, but a thorough ergonomic vision assessment is necessary to ward off the onset of CVS. An ergonomic vision assessment starts with the office layout (whether it is open or partitioned) and includes four reading points or distances. The computer monitor is assessed for six visual components. This assessment takes into account the entire visual needs of the user—text documents, graphics, scanned information, work surface visual needs, and distance visual needs.

In a visual assessment evaluation, the office illumination system is not confined to the components of an electric lighting system. Rather, it comprises all direct and indirect sources of lighting.

Glare and Flicker

Lighting quantity and lighting quality are interrelated components. Lighting quantity refers to the amount of light a system provides (illuminance), as measured in foot candles. What the human eye perceives, however, is caused by the lighting quality factor. Improperly shielded lights whose lamps are in, or peripheral to, the line of sight can cause glare—a quality, rather than a quantity, problem. Glare can also be caused by sunlight through windows.

Reading from a monitor under good conditions is far more difficult than reading the black letters or numerals printed on a sheet of white paper. The edges of computer characters are not as sharp as those of printed text. Most monitors produce a distracting flicker. Flicker fatigues the eyes and, combined with glare, creates a dual visual problem for the user.

Screen brightness, character size, contrast and color are important adjustments that can be made to reduce eye fatigue and help neutralize flicker, while monitor or light repositioning may easily correct glare problems. Selection of these monitor accommodations can be balanced with monitor and document distances.

The Big Picture

Assessments of all physical stimuli in the workplace, taken in unison, contribute to effective ergonomic solutions for the individual computer user. Unless the stimuli of the entire physical environment are properly coordinated and controlled, the body will incur stress, strain and, perhaps, even injury. A vision assessment should be a routine part of your ergonomic evaluation to increase productivity and create a more positive state of mental health, as well as physical comfort. Selected optometrists within each state can perform the computer vision test. The eye exam can be incorporated into routine vision screenings as part of an annual health evaluation.

The preceding article was edited by The New York State Insurance Fund Media & Publications Office. It originally appeared in NYSIF’s Workers’ Comp. Advisor newsletter (January 2005).