Introduction to Vision Ergonomics
Ergonomics is the study of harmony between
man and machine. Right now, over 100 million display screen users worldwide
use computer display screens in their homes and offices. This tremendous
growth in computer technology has created some disharmony between man
and this particular machine!. Awareness is rising in the scientific
community and among users that CRT's can cause physical problems such
as eyestrain, visual fatigue, static charge shock and possible radiation
The Vision Problem
Eyestrain and Visual Fatigue. Scientific research has substantiated
that prolonged CRT use can cause eye discomforts such as eyestrain,
blurred vision, tired and itching or burning eyes.
What does "eyestrain" mean? Olov Ostberg, a Scandinavian ergonomics
expert, describes the range of vision complaints VDT users experience:
Ocular symptoms such as heavy, dry or burning eyes.
Visual symptoms such as difficulty in fixating objects
Systemic symptoms such as dull headaches
Behavioral symptoms such as an increased awareness concerning
eyes and visual tasks
Ergonomic studies in Switzerland and Sweden conclude that frequency
of eye discomforts are related to the amount of working time at the
computer display (Significant increase after four hours).
CRT displays glare is a major contributor to visual discomfort. Reflections
from the CRT. overhead lights, windows and even clothing can cause glare
and wash-out effects which, "fog over" the screen. This decreased
character contrast so that CRT users cannot read displayed information
clearly. The result is a marked drop in accuracy and loss of operation
Static Charges and Radiation Emissions.
Electrical emissions from CRT's can cause static electricity buildup
on the surface of a system A Minolta Corporation survey of professional
secretaries reported 15 percent of the respondents noticed static electricity
when working at CRT's. Besides causing an uncomfortable disruption for
CRT users, static charges also attract dust particles and other airborne
pollutants. This can lead to reduced viewing capacity and static shock.
Public awareness of exposure to electromagnetic fields has been heightened
by publications by Paul Brodeur and others, as well as recent, although
inconclusive, scientific findings. This awareness is causing concern
among CRT users that unfelt harmful effects, especially from the magnetic
portion of electromagnetic fields, may be occurring.
The Vision Solution
OCLI has developed GlareGuard® anti-glare filters specifically to
address the problem of CRT glare, static buildup and E-field electromagnetic
radiation. GlareGuard® anti-glare filters for CRT's and notebook
computers, reduce glare up to 99 percent, enhance image-to-back-ground
contrast, and improve resolution, making images on the display screen
easier to read.
GlareGuard® filters minimise the reflected brightness to which the
human eye is most sensitive by utilising OCLI's patented, multilayer
thin film HEAR (High Efficiency Anti reflection) coating.
HEA is similar to the coating which OCLI applies to the windows and
instruments of NASA spacecraft.
The process is called thin film coating because the thickness of the
individual layers of the coating is measured in quarter-wavelengths
of light. Similar coatings are used on camera lenses.