Optometric Extension Program Foundation, Inc.

Interpreting the glowing symbols on video display terminals (VDTs) has created a new source of stress on our vision system's capabilities.

More than half of all VDT operators experience eyestrain, headaches, blurred vision and other symptoms directly and indirectly related to increased, sustained nearpoint visual stress, associated with the use of VDTs. Visual stress also may underlie complaints of general body fatigue, reduced efficiency at work and higher error rates as the day progresses.

Behavioral optometrists have found that most of these symptoms are alleviated through a combination of correcting workstation conditions, posture, stress-relieving lenses prescribed specifically for VDT operation, and in some cases, through improving vision skills with visual training.

Soon, some 35 million people will be using VDTs. If what has been learned about vision and VDTs is ignored millions will discover that such visual stress can generate serious, often permanent visual and eye problems.

This pamphlet is a guide for making life with VDTs less stressful, more comfortable and more productive.

Humans have hunter-soldier eyes, essential to survival for spotting game or danger at a distance. But during the past half century, nearly all our work and much of our recreation has shifted to seeing within arm's length.

The resulting nearpoint visual stress despite 20/20 distance visual acuity often produces both temporary and sometimes permanent adaptive changes, including nearsightedness, suppressed vision in one eye, poor eye teaming and reduced performance both at work and at play.

Although computer manufacturers have vastly improved their products, some VDT operators find their existing visual difficulties with nearpoint visual activities are complicated by sometimes blurred characters, an increase in the number and complexity of necessary eye movements and conditions, glare and distracting reflections, flicker, focusing shifts, and by sometimes poor lighting

Changes in the way work is done will affect many first-time VDT users. Jobs which formerly allowed physical movement and opportunities to look away from near work now require extended, tiring concentration on a VDT image.

Many people who could handle the visual stress of intermittent near work simply cannot deal with prolonged nearpoint tasks.

Visual Stress Checklist

Eyestrain is a common direct symptom, while the need for shifts in posture and muscular strain resulting from an ill-arranged workstation are among the indirect symptoms.

Direct Visual Signs and Symptoms

Indirect, Visually-related Signs and Symptoms

VDT Workstation Suggestions

Many vision problems can be alleviated simply by making changes, when possible, in the workstation. This checklist may guide you in evaluating vision - affecting conditions where you work

Keyboard, screen and copy should, ideally, be at equal distances from the eyes.

VDT screens should be slightly below eye level (about 20 degrees). Copy should be the same level as the screen.

Locate keyboard so wrist and lower arm are parallel to the floor.

Workstation lighting should provide a 10:3 screen characters 10 times brighter than screen background; room illumination 3 times brighter than screen background.

Each workstation should have an adjustable, shaded copy lamp that can be aimed by the operator without causing screen reflections.

Eliminate glare and screen reflections by moving or tilting the terminal. Overhead light may need baffles. Try not to face toward windows of bright light sources.

Operators should face toward an open space beyond the VDT screen.

Clean VDT screens regularly; they attract and accumulate dust.

Have focus and image alignment adjusted frequently to reduce visual stress.

Vision and performance are enhanced by taking a short break (15 minutes); every two hours. Demanding VDT workloads usually require a short change from VDT work each hour.

The Link Between VDTs and Vision Problems

The optometrist's recommendation may be the key to making work less stressful, less painful, and, more productive. And, you may avoid the onset of more permanent visual and eye conditions now observed by optometrists among VDT operators.

VDT characters on older or infrequently serviced display screens are sometimes fuzzy-edged and are constantly decaying and being regenerated. Add to that scrolling, flicker; screen edge distortions, improper contrast and other disturbing workstation conditions and visual problems may develop.

Symptoms and discomfort are the warning signs that something must be done to reduce the possibility of serious, permanent visual or eye problems that can alter and diminish the quality

How Can Behavioral Optometry Help?

Behavioral optometrists have found that the visual care needs of VDT operators differ from those who work with paper and must include detailed analysis of work situations as well as more extensive, specialized visual testing.

For many people, visual stress can virtually be eliminated specially prescribed stress relieving lenses meant only for VDT operation. These become "tools for that job," not signs of a defect.

Eye teaming and scanning problems may require visual training to develop the ability to efficiently track and move both eyes together.

Behavioral optometrists spend years in postgraduate education to master the complex visual programs prescribed to prevent or correct visual problems and enhance visual performance.

Behavioral optometry is an umbrella term which also includes developmental and functional optometric practices.

Not all optometrists practice behavioral optometry. To find one who does, call or write Vision Extension, or make sure you receive a yes to each of the following questions.

1. Do you make a full series of nearpoint vision tests?

2. Do you make work- or school-related visual perception tests?

3. Do you provide full vision care including visual training in your office, or will you refer me to a colleague if needed?

4. Will you see me again during the year; and periodically, to determine my progress?

 

Pamphlet Copyright © 1989, OEP Foundation, Inc. - A nonprofit foundation for education and research in Vision

Permission to reprint the contents of this brochure granted to P.A.V.E ® - 12/6/96 by: the Optometric Extension Program Foundation, Inc.