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Long hours at your computer don't harm eyes, says expert

A LITTLE CARE: The character size should be three times the size of threshold recognition for your comfort level. — FILE PHOTO: BHAGYA PRAKASH K.

A LITTLE CARE: The character size should be three times the size of threshold recognition for your comfort level. — FILE PHOTO: BHAGYA PRAKASH K.  

Damaging effect has more to do with health and mental fitness

Working long hours on the computer does not damage the eye, asserts Jim Sheedy, a professor of optometry and an expert researcher in the field of vision ergonomics.

‘Myth'

“It is a myth that working on a computer can damage your eyes. Even with children, the damaging effect of sitting long hours in front of the computer has more to do with health and mental fitness rather than damage to the eyes,” he says. The expert, who has spent over two-and-a-half decades studying the relationship between visual comfort and the environment, spoke to The Hindu on the sidelines of a lecture on “Vision and Computer Displays: Matching humans with Technology” at the Sankara Eye Hospital in Bangalore.

“I would imagine this is a great concern and topic of interest among young professionals, particularly in Bangalore,” quips Prof. Sheedy, referring to the burgeoning IT services industry that Bangalore is best known for. But, if one would pay attention to basic principles of vision ergonomics, such as optimal lighting – the best brightness level on a computer is that which blends in with your surroundings – posture and height of the computer screen and text size or font type, reading on a computer cannot damage the eye or lead to any vision deterioration.

The test

So what is the optimal font, light or view size? Prof. Sheedy explains that character size should be three times the size of threshold recognition. So, do this simple test: determine the farthest distance at which you can barely read the text. Your maximum viewing distance should be one-third of that distance, he recommends. As for font size, he says that sizes between 10-12 are optimal for viewing, and these sizes have already been standardised by the publishing industry. As for font type, Prof. Sheedy is sure that the popular Times (or any serif font) is not suitable for computer viewing — he recommends Verdana as the ideal font.

But besides making small changes in the computer display, the screen height and the lighting in your room are critical. For lighting, test for glare by shading your eyes with your palm. If reading is easier in this position, that means your lighting is all wrong, he says. Blinds, dimmed lighting, removing white surfaces and insisting on indirect lighting can make all the difference, he said. Looking down at the monitor, optimally 10 to 20 degrees below the straight-ahead position of the head is the best practice.

Prof. Sheedy founded the first visual ergonomics lab at the University of California at Berkeley School of Optometry that pioneered research in understanding the effects of one's visual environment on the performance and comfort level of eyes, particularly in the context of workplaces.

3D, virtually

On 3D, a technology that has moved from being a cinema experience to desktops and homes, Prof. Sheedy says that research proves that there is a definite discomfort level associated with 3D viewing. While technologists are trying to find ways, as had been tried in the movie Avatar, to reduce the effect of 3D on the eye by cinematography techniques, it still does affect the eye, he concedes. “3D is powerful but there are certainly issues there. In the real world there is a fixed relationship between the convergence and accommodation functions of your eyes. In the virtual world (when a 3D environment is created) you see things at different distances (virtually) but the form does not really change,” he explains. This convergence, without accommodation (of light) in the eye, creates irritation.



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