Visual stress and eye muscle fatigue from the use of computer video display terminals, or VDTs, have become common.
There are two sets of muscle systems involved in what is commonly called eyestrain. The muscles controlling eye movement direct the eyes toward what they want to see. The ciliary muscles focus the eyes by relaxing or contracting, causing the lenses to flatten for far vision or become rounder to see up close.
After extensive computer use, the eye muscles may tire, the ability to concentrate may diminish and eyestrain and headaches may occur. Other symptoms may include eye irritation, difficulty focusing, double vision, changes in colour perception and muscle spasms.
Correcting workstation conditions can eliminate or minimize many of these problems.
Cut glare and reflections on the VDT screen with an anti-glare filter or screen. Place the screen at right angles to a window. Wipe the screen often with an anti-static cloth. Use shades or blinds on the windows and matte-finish wall paint. Turn down or shield overhead lights or use a desk lamp instead.
Anti-reflective lens coatings for eyeglasses are also available.
Adjust the height of the monitor so the screen is slightly below eye level. The screen should be about 20 inches from your eyes. The copyholder should be at the same level and angle as the screen and as close to the screen as possible.
Take breaks every couple of hours and take your eyes off the screen. Sit facing a visual relief area, an open space that allows you to look away from the computer from time to time.
Make a conscious effort to blink frequently to maintain eye moisture. You blink less when you stare at a computer screen and your eyes get dry.
It is important for people who work on VDTs daily to have regular eye exams. An eye care professional can evaluate individual needs and prescribe eyewear to help reduce avoidable eyestrain. Glasses and contacts for other activities may not be right for VDT use.
