The CVS Epidemic
How You Can Make Computers Easier on the Eyes

Your role in managing this 21st Century epidemic.

by Jeffrey Anshel, O.D., Encinitas, Calif.

There are many compelling reasons for optometrists to become more aggressive in diagnosing and treating the ocular and related symptoms that come with computer use. Here are a couple hundred million reasons:

• More than 70 million Americans use computers every day at work, the Bureau of Labor Statistics (BLS) reports. Predictions indicate that fully half the working population will be using computers by next year.

• Some 140 million people use the Internet, industry estimates say.

• More than 30 million U.S. households own a personal computer, and new computer sales exceed those of television sets.

• More than 11 million Americans telecommute, the Massachusetts Institute of Technology reports.

• In 1996 more than 15 million Americans sought eye exams primarily due to problems related to computer use, an increase of 50 percent in five years. About 40 percent of these patients received a specific VDT-related prescription.

• The number of workers over 55 is expected to grow 42 percent over the next five years, the BLS says.

What all these numbers have in common is that they're sure to increase as we become more dependent on computers. A National Institute of Occupational Safety & Health (NIOSH) study in 1994 showed that almost nine out of 10 computer-using patients tell doctors that "eyestrain" is their main complaint, and that more than one out of five do not receive an adequate resolution to their problem.

Computer Vision Syndrome—CVS—is big. The AOA defines CVS as "the complex of eye and vision problems related to near work which are experienced during or related to computer use." It consists of a series of signs and symptoms computer users typically experience, and may be caused by this near-point activity. Symptoms include "eyestrain," blurred vision, headaches, back and neck aches, dry eyes, diplopia and distorted color vision. You probably won't have patients walk into the office and say, "I have CVS, doc." So, it is imperative that you know how to identify these symptoms and how to successfully resolve them.

This first installment in this Review of Optometry four-part series, "The CVS Epidemic," looks at the scope of this problem and describes a work-up you can use for identifying specific symptoms. Subsequent installments will deal with dry eye in computer users, ergonomics for the compuer work station and how you can promote your CVS practice.

The Right Questions
Your first line of attack in identifying computer-related vision problems is to ask the right questions. You can't overemphasize a good case history because the patient uses his eyes in every task, every day. If we don't know how the patient uses his eyes in his own environment, then we cannot adequately prescribe correction for the situations he may encounter. So, it's critical that your patients fill out a questionnaire that asks for specific working distances to their VDT screen, as well as other viewing distances and environmental factors.
(See sample.)

So, since computer use is such a unique working situation, what kind of testing procedures should you do? Do you need special equipment? What about lighting? Should you make "ergonomic" suggestions? These are all valid questions that you should ask when evaluating the computer user. Let's take a look at some possible answers.

Starting the CVS Exam
CVS is essentially a near-point problem, so you need to do near-point testing. Our standard reading distance is 16 inches. Yet at many computer stations the actual working distances of the monitor and hard copy are different. Ask patients to obtain the working distances at their work stations before they come in for the exam. When you do standard near-point tests, you'll have to extrapolate their working distance since there are no norms for the 20-30-inch working distance ranges.

Testing the VDT Patient
Here are some tests/procedures you should include in your ssessment of the VDT-using patient:

Patient history

VDT questionnaire

Distance refraction

Near (16-inch) refraction

Fusional reserve



Accommodative amplitude and facility

Specialty equipment (PRIO or Eye-CEE  System)

Trial frame tentative Rx at VDT distance


Some of the standard tests you should do: fusional reserves, phorias, PRA/NRA, accommodative amplitude and facility, and anything else that you feel can accurately assess near-point stress.

A few tools have been designed to obtain visual data for computer users. One of these is called the PRIO unit. This is a self-illuminated simulated computer screen which suspends on the near-point rod at the patient's working distance. You perform book retinoscopy while the patient views the image on the unit. Several doctors have used this apparatus successfully, and there is some valid research which points to its effectiveness. It also fails to account for several factors which may contribute to eye problems for computer users. For instance, it does not consider the effects of binocular vision dysfunction. Also, you must assume that a patient is viewing a particular color monitor, which may or may not be accurate.

Another tool is the Eye-CEE System, developed in the United Kingdom. This interactive software program performs a vision screening right on the user's screen. It also contains a questionnaire that can assist in determining if any stated problems are visual or environmental in origin. It generates information about the patient's visual status when he or she is using the computer in the normal working environment. It does not, however, assist in finding a final prescription for the computer-using patient.

Since the battery of tests we're able to perform continues to expand, how does the busy doctor fit additional testing into the practice? Start by making your staff aware of the various occupations that require computer use. This helps them pre-determine who will need special attention.

Most occupations these days depend on computers. For example, you might think that a homemaker or mother wouldn't have a concern in this area. Or there is the manager who claims to just glance at a computer for less than an hour a day at work. These people may be spending several hours a day "surfing" the Internet, so try not to pre-judge your patients' computer use. You may need to ask all patients about their computer habits.

What's Behind CVS
Three factors contribute to the development of CVS:

• The condition of the patient's eyes and/or correction.

• The patient's physical working environment.

• The patient's work habits.

We've discussed some of the ideas for testing, but what recommendations should you make regarding environmental influences? The area of "ergonomics" is not new—it was first developed in the 1940s to assist the military in producing efficient equipment and armaments. Ergonomics is essentially a science of fitting the person to his or her job, while minimizing stress and strain on the individual.

This has become more popular since computers came onto just about everyone's desktop. These devices require the user to sit in a unique posture. The longer a person sits at a computer, the more pronounced the problems this strange posture causes. The most widely known side effect of computer use has been carpal tunnel syndrome. I believe that CVS will be the carpal tunnel problem of the next millennium.

So, it's important for us to establish ourselves as the experts to address this condition. We should be able to give our patients advice on monitor distance, monitor height, head position, desk viewing distances, general and task lighting, windows, glare and maybe more. Since the "eyes lead the body," we might even be able to resolve some back and neck aches our CVS patients present with.

The individual's work habits also have a major influence on the manifestation of CVS symptoms. A user who only spends an hour a day at a computer screen may not have the same problems as a data entry or customer service person who looks at the screen continually. I've developed several "tips" for the patient to use as a reminder on how to be comfortable with his or her computer. I call this the "3-B" approach: blink, breathe and break.

Blink. We tend to blink much less when we're viewing a computer than at other times. This might be a combination of poor monitor placement and intense viewing conditions. In any case, we must emphasize to our patients the importance of regular blinking. I recommend that they put a small sticky note on their monitor which says "blink" to serve as a reminder.

Breathe. Regular breathing is important to maintain blood flow and mental alertness. Occasional deep breaths will help people relax while viewing their screen.

Break. We can recommend our patients take several breaks during the day, but that makes it difficult for people to get their work done. So I've come up with the "20/20/20" rule for breaks: Every 20 minutes, take 20 seconds and look 20 feet away. This seems to be easy for patients to remember.

I suggest one of two possible scenarios for testing your computer-using patients. If you've already determined that they are "significant" computer users (about three or more hours a day), simply fax or mail them the questionnaire prior to their first appointment. This will allow you to conduct an "extended" exam which can include several near-point tests at their customary computer viewing distance, as well as environmental counseling, if appropriate. If you did not determined this prior to the initial exam, then re-appoint them for a special VDT exam in which you have them fill out the questionnaire, perform several appropriate tests (possibly incorporating the PRIO or Eye-CEE devices) and make your recommendations after that testing is completed and evaluated.

Successfully prescribing correction for computer users is a challenge, and the rules are always changing. More occupations require the use of computers, and the population is aging. These workers will not be doing physically demanding jobs. More likely, they'll be using computers and will require special attention to address this visually demanding task. However, with the right perspective of the problem and a few simple tools to use, you can make your patients happy computer users.

Next month: Diagnosing and treating dry eye in computer users, by Eric S. Donnenfeld, M.D.

Dr. Anshel, a principal of Corporate Vision Consulting, has authored several books and lectures nationally on computer vision syndrome. He has a financial interest in the Eye-CEE device he mentions.


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