ITHACA, N.Y. -- Optical glass glare filters on computer monitors can dramatically reduce health and vision problems related to computer glare and help boost productivity in full-time computer users, according to a new Cornell University study.

After using a glass anti-glare filter, the percent of daily or weekly problems related to lethargy/tiredness, tired eyes, trouble focusing eyes, itching/watery eyes and dry eyes was half what they were before filter use for people who use computer monitors all day at work, said ergonomist Alan Hedge, Ph.D., Cornell professor of design and environmental analysis and director of the Human Factors Laboratory.

Also, 80 percent of users reported that the filters made it easier to read their screens and more than half said that the filters helped their productivity.

"I was very surprised how well the filters worked in this study," said Hedge, who believes this is the first field study of computer monitor filters. "Seeing such large differences in an ergonomic intervention is very unusual. It leads me to conclude that if there is screen glare, using an optical glass glare filter is one of the most effective things you can do to improve the visual environment for people working on computers."

With Daniel McCrobie, Ph.D., a corporate ergonomist at Honeywell, Inc. in Phoenix, Ariz., and Cornell graduate student Simone Corbett, Hedge set out to determine whether a good quality anti-glare filter actually benefits workers. To find out, they surveyed 194 full-time computer workers in eight buildings at Honeywell. An initial survey asked about lighting and screen glare problems; a second survey queried the same workers one month after two-thirds received a glass anti-glare, anti-static screen filter. The final survey was conducted one month after the remaining third also received glare filters.

In the study, monitor size, brand and screen background/text colors varied; all the filters had the same optically coated glass that met specifications set by the American Optometric Association (AOA) for glare reduction.

"Overall, worker reactions were extremely positive to the filters, and the vast majority of workers said they liked using them," Hedge wrote in a new report issued by the Human Factors Laboratory at Cornell. The findings will be presented to the Human Factors and Ergonomics Society conference in Philadelphia in September.

The researchers found:

• 75 percent of workers reported glare problems before filter use; less than one-third reported problems after given a filter.
• 89 percent said that the filters improved the quality of the screen image by enhancing sharpness, contrast, color and brightness; 81 percent reported that the filter made it easier to read the screen and 73 percent said text was clearer.
• 34 percent said there was less screen flicker with the filter.
• the percent of workers reporting symptoms of lethargy/tiredness went from 78 percent before filter use to 36 percent after filter use; tired eyes from 86 percent 40 percent; trouble focusing eyes from 60 percent to 33 percent; itching/watering eyes from 50 percent to 28 percent; dry eyes from 52 percent to 24 percent; and headaches from 53 percent to 32 percent.

"Keeping the filter clean and free from fingerprints that blur the screen was the greatest problem reported by users," Hedge said.

Glare on computer screens is caused by light through windows, overhead lighting, desk lamps, white paper near the screen and even bulletin boards and white clothing. Other researchers have reported that two-thirds of computer workers suffer from tired eyes and 75 percent from eyestrain. AOA members report treating more than 8 million cases of work- related eyestrain from computer use each year. Hedge suspects that the filters would also benefit casual and part- time computer users who suffer from eye strain and other related problems.

To cut down on glare, computer workers in the past had to choose from among plastic, polarizing or micromesh filters, yet no field studies ever evaluated the effectiveness of these different types of filters and many computer workers still complained of visual problems. Now, new types of optically coated glass for filters have been developed and these are sold by several companies. These filters, which generally cost less than $100, have at least four layers of anti-reflective coatings on each side of the glass and are designed to meet AOA specifications.

The filters used in the study also were electrically grounded and minimized electrostatic shocks to workers and significantly reduced dust accumulation on the screen, Hedge reported. The filters were donated by SoftView Computer Products.

Recently, Hedge and McCrobie served on the committee that has revised the ANSI/HFS 100 standard for computer work enviornments, which included recommendions for optically- coated glass anti-glare filters, for the Human Factors and Ergonomics Society. They also recomend the use of solvent free filter cleaners that do not contribute to any air quality problems or degrade the filter coatings. These proposed standards are under review.

Next, Hedge, who teaches courses in human factors, ergonomics-anthropometrics, the ambient environment and environmental analysis in applied ergonomic methods, plans to compare the effectiveness of various optical glass anti-glare filters because filters vary in how much light they transmit and how they affect color value.

The report, Effects of Using an Optical Glass Glare Filter on Computer Worker's Visual Health and Performance: Results of an Ergonomic Field Study, is available for $15. The report can be ordered by calling (607) 255-2168, fax (607) 255-0305. For further details, contact Dr. Alan Hedge, Human Factors Laboratory, DEA, MVR, Cornell University, Ithaca, NY 14853, phone

(607) 255-1957 or e-mail <ah29@cornell.edu>. More information on the Human Factors Laboratory and its research is available on the World Wide Web at ergo.human.cornell.edu.