Wright State University
Policy number: 6050
Subject: Video Display Terminals Ergonomics
Date issued: April 1994
Authority: National Institute
for Occupational Safety and Health; National
Safety Council
Reference: Department of Environmental Health and Safety
6050.1 History
The Ohio Occupational Safety and Health program for public
employees has determined that the university is responsible for a workplace
that is not harmful to the health and well-being of it's employees.
Extended work at a video display terminal (VDT) may result in an employee
experiencing a wide range of conditions including but not limited to headaches,
general malaise, and visual and musculoskeletal strain. However, the majority
of complaints are eye fatigue, eye irritation, blurred vision, and pain and
stiffness in the neck, shoulders, back, arms, wrists, and hands.
6050.2 Purpose
The purpose of this guide is to educate, promote a preventive
approach, and attempt to reduce lost time from work.
- Education. Extended time at a VDT workstation may have a negative
effect on the health and productivity of employees who are encouraged to
bring to the attention of their supervisors any problems that they may be
encountering. The Department of Environmental Health and Safety (EHS) will
assist in addressing those concerns and in conducting workstation evaluations.
Ergonomically designed furniture is available through the Purchasing department.
- Prevention. In order to promote a preventive approach, workstation
exercises are recommended to provide relief from workplace stress and musculoskeletal
strains. EHS will provide brochures and posters. Additionally, to relieve
stress and fatigue, the National Institute for Occupational Safety and Health
(NIOSH) recommends alternating VDT work with non-VDT work. The National
Safety Council and NIOSH recommend the following guidelines for the ratio
of VDT work to non-VDT tasks:
| Operator VDT Workload |
Frequency for Non-VDT Tasks |
Length of Non-VDT Tasks |
Moderate (less than 60
percent of operator time looking at screen) |
Every two hours |
15 minutes |
Heavy (greater than 60
percent of operator time looking at screen) |
Every hour |
15 minutes |
-
Lost Work Time. Not only does this guide attempt to reduce lost
work time due to VDT related problems, it also attempts to reduce workers
compensation payments for medical expenses associated with injuries from
extended VDT operations.
6050.3 Ergonomics in the Workplace
Workstation design. When designing a workstation, it is possible that more
than one individual may use the station; and, therefore, flexibility in the
height of the work surface and chair, as well as the reach distance of the
operator, should be considered. Upon request, EHS will provide information
on general design criteria, arm and wrist supports, as well as ergonomic evaluations.
- VDT height. The optimum height of a VDT for operator comfort is
approximately 28 inches from the floor to the normal rest position of the
operator's fingers. This height permits the operator to sit with arms nearly
horizontal, shoulders comfortably relaxed, and wrists at the proper angle.
- Keyboard. The keyboard should be located so that the upper arms
hang straight down from the shoulders and the forearms are horizontal or
lower.
- Screen. The screen should be placed in order that glare is kept
to a minimum, the operator's line of sight is horizontal to 20 degrees down
and falls comfortably in the upper half of the screen, and a distance of
15 to 20 inches from the operator's eyes is maintained.
- Chair. The chair should be in a position so that the thighs are
permitted to rest approximately horizontal without being pinched by the
front edge of the chair, the calves hang vertically, and the feet rest squarely
on the floor or on a footrest.
- Illumination. A general room lighting level of 500-700 lux (50-70
foot candles) is normally recommended in the vicinity of VDT workstations,
but may need to be higher depending upon the visual demands of other tasks
performed in the same work area. Glare is a common problem at VDT workstations
and can be very discomforting to the operator, as well as have a negative
effect on productivity. To reduce glare, drapes, shades, and/or blinds over
windows should be closed, especially during direct sunlight. The terminals
should be positioned so that glare from windows and overhead lighting are
not reflected on the VDT screen. Screen hoods may be installed to shield
completely or partially the screen from reflection. Anti-glare filters may
be installed on the VDT screen. Direct lighting fixtures may need to be
recessed and baffles may be used to cover light fixtures to prevent the
luminaries from acting as a glare source, or special covers on light fixtures
may be used to direct the light downward rather than allowing the light
to diffuse.
- The following figure illustrates an ideal workstation design.
6050.4 Eye Examination
- Employees who meet the following criteria should have an eye examination
before beginning VDT work and be tested annually thereafter.
- An employee's job description must list VDT operations
as a requirement of the position. VDT operations must be continuous for
four or more hours per day and be a single detailed task. Exception: An
employee who wears tri-focal lenses and is required, as part of his/her
job description, to operate a VDT should be encouraged to have an eye
examination regardless of the number of hours spent per day at a VDT station.
Employees who wear tri-focal lenses normally experience visual fatigue
and musculoskeletal stress after relatively short operating times at a
VDT. An eye examination for those individuals will determine if mono-
or bi-focal lenses can be prescribed and worn by those employees for VDT
operations. Additionally, an employee must have completed his/her probationary
period.
- When an employee believes that he/she meets the above criteria and
is eligible for an eye examination, the employee should bring that fact
to the attention of his/her supervisor.
- The immediate supervisor shall review the job description and daily
work activities of an employee to determine if the criteria for an eye
examination has been met. If the immediate supervisor cannot reach a decision,
the Department of Human Resources shall make the final decision.
- An eye examination shall meet the recommendations of the latest guidelines
published by the American Optometric Association. The Department of Environmental
Health and Safety will, upon request from an employee's supervisor, provide
a list of the recommended tests.
- An examination may be given at any qualified location, provided the
American Optometric Association recommended tests can be conducted.
- Payment for an eye examination
- An employee and his/her hiring department will each pay 50 percent of
the cost of an eye examination.
- An employee shall pay the full cost of new eye wear including lens
and frames.
- The university is not obligated to pay any portion of an eye examination
that does not include all of the American Optometric Association recommended
tests [refer to paragraph 6050.4 a) 4)].
6050.5 Additional Information
Additional information and an ergonomic evaluation may be obtained from
the Department of Environmental Health and Safety, 104 Health Sciences Building
(775-2215).