Article Date: 9/1/2006

computer vision syndrome
CVS:Constructing a New Approach to Visual Ergonomics

How to manage patients with computer vision syndrome � from your office to their computer stations


Symptoms of CVS

Blurred near vision
Blurred distance vision
Dry/irritated eyes
Watery eyes
Double vision
"Night blindness"
Color distortion
Light sensitivity
Tired or burning eyes
Eye pain
Excessive blinking or Squinting

Over more than three decades in private practice, I've seen an increasing number of patients with symptoms such as headaches, blurred vision, dryness, tired or burning eyes and eyestrain. These symptoms, which may also include color distortion or double vision, are known collectively as Computer Vision Syndrome (CVS)

Approximately 75% of all jobs in the United States now rely on computers (Kanitar, et al.) and reported that employees in those jobs spend an increasing share of their work hours at the computer. Adults and children also play video games and use the Internet at home, as well as rely on "mini-computers" (such as a Palm Pilot, Blackberry or cell phone) wherever they go, compounding the effects of eyestrain at work. Not surprisingly, this dramatic shift in the way we use our eyes has led to problems.

I specialize in visual ergonomics, and it's a topic I believe colleagues ought to pay much closer attention to. With so many patients suffering from computer-related problems, the ability to diagnose and treat CVS can be a practice growth engine. Let me show you how.

There's a place for us

Studies estimate that the vast majority (75 to 90%) of those who work on computers experience at least some of the symptoms of CVS. According to the National Institute for Occupational Safety and Health (NIOSH), nearly 80% of those who work at a computer for more than two hours a day suffer from the symptoms of CVS. While less than one in four regular computer users suffers from carpal tunnel syndrome, three times as many experience CVS.

We can help patients evaluate their work environments and habits (without physically going into their offices) and can play an important role in recommending ergonomic changes. In addition, providing regular vision care and prescribing the right vision aids can help alleviate patients' symptoms. Treating CVS should drive new referrals, keep existing patients happy with their contact lenses and benefit the practice financially through prescriptions for new products and lenses.

Diagnosing CVS

The Right Stuff

Here's a list of manufacturers that make lenses designed for computer use:

Essilor International

Prio Corp.

Rodenstock U.S.A.

Shamir Optical

Sola International

Carl Zeiss Vision

Many patients come in for an exam with general, vague complaints. Contact lens patients are especially prone to say that their contact lenses, "don't feel as good as they used to," or that they bother them at work.

Optometrists who ask the right questions will find that these complaints are often computer-related. I ask every patient about his or her computer use � I've learned never to assume that someone is too old or too young for that question. If patients are bothered by any of the symptoms of CVS, I obtain more specific information about their work habits and position of their computer equipment. I also ask patients to check off symptoms they experience from a list of about a dozen potentially CVS-related problems (see "Symptoms of CVS," page 37).

In addition to the questionnaire, I take a full battery of near-point tests, including binocular balance, fusional reserves and accommodative abilities. While the symptoms of CVS can manifest in patients who don't use computers, the diagnosis of CVS is made in conjunction with the symptoms the computer-using patient mentions.

You might consider a "computer vision examination" as a separate battery of tests for computer-using patients. Because our standard exam is now so full of refractive and eye health procedures, a return examination could be an additional source of revenue. Send patients back to their offices with a questionnaire that requires them to take specific measurements of monitor and keyboard distances and elicits the specific lighting arrangement and other ergonomic conditions. On the return visit, conduct an environmental review with the data gathered, and perform near-point and dry eye testing. You can also perform this evaluation right after the routine exam, if necessary. A fee comparable to the contact lens examination is appropriate.

There are currently no codes for CVS. However, the symptoms related to computer use (such as eyestrain, accommodative spasm, etc.) do fall into the category of visual stress. You can legitimately submit them as such to insurance companies.

Visual Ergonomics 101

Here are eight tips you can give patients to implement right away to reduce the risk of CVS and make computer work more comfortable:

1.   Position your computer monitor five to nine inches below the horizontal line of sight so that when you look straight ahead, you look just over the top of the monitor. 2.   Sit far enough away that you can't touch the monitor without leaning forward. A good minimum working distance is about 24 to 26 inches.
3.   If you use a laptop frequently, get a separate monitor and/or keyboard.
   Set computer monitor contrast at high.
5.   Turn down overall room lighting and use a task lamp for reading papers.
   If you have a window, position the computer so that the window is off to the side, not directly in front of, or behind the desk.
7.   Put a note that says "Blink" next to your computer screen.
   Every 20 minutes, take a 20-second break and look at something at least 20 feet away.

Treating CVS

Treating CVS involves educating your patients about the appropriate adjustment and placement of computer monitors, lighting control, good preventive vision care habits and regular professional eye care. You can also help patients take advantage of new contact lens and spectacle products designed for CVS and computer-related vision needs.

Improving work habits

Most people sit too close to their computers and place the monitor too high on the desk, forcing them to look straight ahead or slightly upward at their screen. An upward gaze exposes 40% more of the cornea, which dries out the tear film and compounds the effects of the already dry environment in many office buildings. This is especially hard on contact lens wearers, who typically struggle with dryness anyway. So the first change I generally recommend is to lower the computer monitor (see "Visual Ergonomics 101," page 38).

The next biggest offender in office settings is the lighting. Most offices are far too bright for comfortable computer use, so I advise dimming overhead lights directly above the computer.

It's also very important to consider work habits such as how often people take breaks. Studies show that we spontaneously blink 18 to 22 times per minute under normal conditions. But during computer use, most likely due to the increased visual attention required, the average blink rate drops to seven per minute, or about one-third the normal rate. I've noticed that people playing video games blink even less often. This allows the cornea to dry out and is a significant cause of CVS symptoms.

Lowering the monitor and increasing awareness of blinking can help patients improve their blink rate. They also need to take frequent, short breaks from looking at the computer to maintain greater flexibility in focusing. I recommend the "20/20/20 rule." Take a 20-second break every 20 minutes. Focus your eyes on points at least 20 feet from your terminal. Keep your eyes moving while looking at objects at various distances.

Defining CVS

According to American Optometric 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."

For additional information, call the AOA Clinical Care Center at the St. Louis Office at (800) 365-2219 x 244 or 245.

Computer work is particularly stressful for contact lens wearers. Long, non-blinking phases may cause the surfaces of most lenses to dry out, which can lead to discomfort and a loss of visual clarity. In one survey of more than 2,000 current and former contact lens wearers, time spent in front of a computer was the activity most frequently cited (41%) as causing discomfort while wearing lenses. Left uncorrected, CVS problems could lead to contact lens dropout.

Refractive lens issues

It's important that computer users have a current, accurate spectacle or contact lens prescription and that their contact lenses are clean, well-fitting and healthy (or their glasses free of dust and scratches).

I try to put my contact lens patients in the most comfortable lens possible in order to alleviate the dryness and discomfort that most suffer. I've had great success with Acuvue Oasys with Hydraclear Plus (Vistakon), a silicone hydrogel lens made from senofilcon A.

Even with a lens that's comfortable for them, I still recommend that patients try to blink more frequently. I also prescribe an oral nutritional supplement containing essential fatty acids.

Kids Today

We've all seen for ourselves that children spend a lot of time on computers, but did you know that:

In the United States alone, 54 million children (or 90% of school-age children) use a computer at home or school.

A study at the University of California at Berkeley found that 25% to 30% of children who use computers need corrective eye wear in order to work safely on them.

Besides the rise in what some experts call "environmental myopia" in children, too many hours spent on the computer may contribute to other dangers as well. According to the children's advocacy group Alliance for Childhood, the high number of hours many children spend on the computer place them at increased risk for repetitive stress injuries and obesity. The group warns that children's visual systems are immature, and long periods in front of monitors may retard their visual-spatial awareness.

To prevent Computer Vision Syndrome in children, experts recommend arranging computer workstations to accommodate a child's smaller size. This means changing the viewing angle of the monitor, making sure the child is 18 to 28 inches from the monitor and placing the keyboard within comfortable reach.

For patients who wear spectacles, I often prescribe a second pair of glasses. Regular progressive lenses, which so many patients wear these days, are really not appropriate for intensive computer use. For the office, I prescribe "computer glasses" with occupational progressive lenses. Like regular progressive lenses, these have no lines. They feature an intermediate zone at the top for computer viewing and a near zone at the bottom for reading material. The lab will compute the prescription for intermediate as long as you provide the full prescription (distance and add with near PD).

Patients who wear multifocal contact lenses don't have the same issues as spectacle wearers because the designs vary. Many of these lenses do allow intermediate vision, but it's important to target them for the patient's actual working distance to the computer. Those who wear bifocal, monovision or single vision contact lenses may also want to consider wearing a pair of computer glasses over their contacts.

Seizing opportunities

If you're interested in visual ergonomic consulting, be proactive. I ask patients with CVS symptoms who is responsible for employee health and safety at their workplace. I then contact that person directly and say that I've seen some employees from the company who have visual stress related to computer use. I then offer my services in several ways: I can conduct an on-site evaluation for the individual patient or an evaluation of the entire workplace. I can also provide a lunch-time "brown bag" seminar on ergonomics.

Providing such services can expand your practice as you become known as a computer-vision specialist. Of course, you must do this without violating patient confidentiality.

There's no end in sight to the proliferation of computers in our lives. Doctors who question patients about computer use, identify ergonomic problems, and prescribe the right refractive correction and dry eye aids will reap the rewards of happy patients with improved vision and ocular comfort. This should keep patients in their contact lenses, bring them in for regular eyecare visits and generate patient referrals.

References available upon request.

Dr. Anshel is the founder of Corporate Vision Consulting and the author of "Visual Ergonomics in the Workplace." He is also in private practice and is a consultant for Vistakon and BioSyntrx. Dr. Anshel offers the CVS Eyecare Seminar to train doctors in becoming specialists in the area. Contact him at (760) 944-1200, or

Optometric Management, Issue: September 2006