Every workday, between 7 and 10 million Americans use "video-display" computer terminals on the job. And an alarming number of these workers say they are experiencing "terminal illnesses" -- ranging from eyestrain to neck pain, skin rash and irritability.

Since their introduction into the workplace about 10 years ago, video-display terminals (VDTs) have been linked to a wide variety of disorders including cataracts, birth defects, altered behavior and heart disease. In response to growing concern over these possible health hazards, the National Research Council (NRC) conducted a symposium last week to explore one of the VDT users' most common complaints: vision disorders.

Experts from across the country and from Europe addressed an audience of more than 200 scientists, union and corporate representatives at the National Academy of Sciences. The symposium is part of a 15-month study, begun earlier this year, conducted by NRC's Committee on Vision with support from the National Institute for Occupational Safety and Health (NIOSH).

"In the near future a significantly large portion of the American public will spend a significantly large portion of their day interacting with a VDT," noted Marvin Dainoff of NIOSH.

"The rapid and overwhelming pressure towards office automation, in clerical as well as professional jobs, plus the skyrocketing use of home computers . . . means a solution is now critical.

"I'm convinced that something is different about VDT work that has not been seen in the workplace before."

A major problem, however, with existing studies of VDTs and health hazards, conceded Dainoff, is that they have not established that it is the VDT itself, and not some other factor -- like a bad relationship with the boss -- that causes the reported health problems. The operator's own visual problems -- such as astigmatism or use of bifocals or contact lenses -- may also be a factor.

"There is a lack of data," he said, "on causal linkages between aspects of the VDT workplace and specific strain."

The root of the problem may not be the VDT itself, he said, but poor "task structure" and workplace design.

In his overview of existing research on VDTs and vision, Dainoff cited studies -- admittedly undefinitive -- that show VDT users reporting significantly greater incidence of vision problems than workers who do not use computers. Among the problems cited: eye fatigue, shooting eye pain, blurred vision and temporary nearsightedness.

Dainoff also noted a link between the type of job and the incidence of reported complaints. Professional workers -- usually programmers and editors -- reported fewer ill effects than clerical workers. In some studies, clerical workers involved in "screen intensive work" such as data entry reported the most complaints.

"I've gone into VDT installations," noted Steven Sauter of the University of Wisconsin, "where they've spent literally hundreds of thousands of dollars on systems . . . then placed VDTs up against windows, exposed to glare. Or they've put equipment in hot, noisy, crowded environments not adapted to VDTs."

The "most improvement for the least cost," Sauter said, may come from improved workplace design and job changes. "Providing more frequent breaks may be better for worker health and more cost effective for management."

Design changes also may help, said Lawrence Stark of the School of Optometry at the University of California at Berkeley. Among his suggestions:

* Position the VDT so a worker can look down at it "as he would to a typewriter."

* Use black characters on a light background (which he says is easier on the eye).

* Eliminate the "flicker" that exists on some machines.

The key to alleviating operator discomfort, said K.H. Eberhard Kroemer of Virginia Polytechnic Institute (VPI), is ergonomics -- the science of adapting work or working conditions to fit the worker.

"We have to fit the task to the people," he said, "not the people to the task. The VDTs by themselves are not bad. It depends on how we use them. The operator, equipment, task and environment must be dealt with as a unit.

"Most of the ergonomic principles of workplace design exist now. It's a question of putting them into use, because very soon -- within two to five years -- the technology of the video workplace will be frozen."

Added Harry Snyder of VPI: "Be aware that we may be talking about more than worker satisfaction . . . but about a serious legal issue, too."

Among other suggestions for alleviating VDT operators' discomfort:

* Make sure the "work station" includes a chair that adjusts to different body dimensions and allows the user to change his or her position.

* Use a VDT system that has an adjustable screen separate from the keyboard.

* Provide an armrest or handrest so the operator can relax arms and hands between keystrokes.

* Allow ample leg room, with space for the operator to elevate feet slightly, if desired.

* Provide a "hood" for the screen to avoid glare.

Consider indirect lighting for best screen illumination and the least glare and "shadow."

* Make sure the system's "scrolling" function is not jerky, but has a smooth "Hollywood" motion.

* Involve users and unions in designing the system.

* Educate operators in how to use and adjust the system for their comfort.