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New Study Links Computer Vision and Productivity
March04

A study published in the January 2004 issue of the AOA Journal, the publications of the American Optometric Association, reveals that even a slightly inaccurate vision prescription at the computer can significantly affect workers productivity.
The double-masked, placebo- controlled, randomized study done at the University of Alabama at Birmingham School Optometry, the first of its kinds ever conducted, drew the following conclusions:

Uncorrected computer vision, even where there are no symptoms or where the computer screen appears clear, can affect worker productivity and accuracy.

A miscorrection of as little as .5 diopters, which translates to just two “clicks” in a patient’s eye exam, can affect productivity by approximately 9% and accuracy by 38%.<


There can have a significant impact on organizations that rely on employees using computers. For example the employer of an individual with a salary of $60,000 a year would theoretically reap a gain in productivity of $5,400 (9% of $60,000) minus the cost of the eye exam and computer glasses of about $300. This means in the case of this employee an organization would reap a cost. Benefit ratio of 18 to 1 (or $18 for every $1 spent). For large companies, the difference would have a huge impact on the bottom line.

“The study is important because over half of America’s workforce spend their workday in front of computers today,” said Kent Daum, O.D., Ph.D., the study’s chief investigator. “This study gives employers hard evidence of the financial benefits of providing computer eyewear for employees who use computers.”


It has been reported that as many as nine out of every 10 workers – including computer programmers, graphic artists, editors, architects, insurance underwriters, air controllers, executives and secretaries – experience some symptoms of Computer Vision Syndrome ( or CVS) – e.g. eyestrain or eye fatigue, headaches, blurry vision, neck and back aches. This is why CVS has been called the #1 occupational hazard of the 21st century.
Studies have long shown that the way your eye views the computer image is very different than how they read the printed word in a book or newspaper. The images or pixels on a computer screen have poor edge definition. This can cause a repetitive focusing effort for the eye muscles, which over time generate symptoms due to overuse.

Study Methodology

The University of Alabama at Birmingham team conducted the study by first performing complete vision examinations on subjects ranging in age from 19 to 30 years old. The subjects asked to complete several tasks on the computer that were calculated to assess the of refractive error (i.e. visual accuracy) on their productivity. Using a PRIO tester, a device that simulates one’s vision at the computer, the researchers assessed the subjects’ computer vision using both corrected and uncorrected lenses. The lenses for each subject were then randomly assigned without the subjects or technicians knowing which lenses were used.

The study asked the subjects, while using different lenses, to do various tests that required them to read fonts of various sizes on the computer screen. This included identifying population listings for various counties, matching nonsense words and finding various symbols within a manuscript on the computer monitor. Technicians timed subjects and calculated the number of errors. They also asked them to answer a questionnaire pertaining to visual problems, clarity, symptoms, limitations, etc.

“We found that even when symptoms were not reported and the computer screen was seen clearly, we found differences in productivity and accuracy over time,” said Dr. Daum. “The greater the miscorrection, the greater the decrease in productivity. Yet, even when the subject’s vision was slightly off, productivity was significantly affected. According to Daum, the test also shows that while ergonomics are important in terms of productivity and relief of CVS symptoms, they won’t in themselves fix visual problem. This he said can only be done with the right computer lens prescription.

Although organizations are under pressure to control costs, a growing number are beginning to understand the direct correlation between computer vision and workplace performance.

“When you have a company that has hundreds if not thousands of employees using computers for hours every day, you’re talking about a considerable impact on productivity,” said Dr. Daum. “Based on the results of our study, there would seem to be a good reason for employers to address this issue.”

In addition, the government is beginning to pay attention. Federal studies have suggested that more research is needed to study the correlation between vision and neck, back and shoulder muscular skeletal problems. OSHA also recommends a vision exam for all computer users.