Using sunglasses is a must when working outdoors. A
worker’s ability to see clearly may be enhanced and visual
comfort most certainly will be improved when wearing the
correct eyewear in the sun.
Sunglasses, particularly polycarbonate lens sunglasses
work by blocking UV radiation and a portion of visible
light. Any polycarbonate lens will block out 100% of
UV radiation, but only dark shaded lenses will adequately
block visible light. Normal light transmission for sun
lenses is generally between 12% and 30%. Lenses that
allow more than 30% of light transmission may not help
the average wearer sufficiently in sunlight, while less than
12% light transmission may be too dark for normal
purposes.
One of the most important problems caused by
over-exposure to the sun’s light is that it decreases the
eye’s ability to adapt to the dark. Normal “darkness
adaptation” by the eye allows the pupil to open widely
and improves depth perception in low light conditions.
These changes in the eye that normally occur in dark
conditions enhance the ability to see clearly particularly
at night. This normal “darkness adaptation” is interrupted
by repeated over-exposure to bright sunlight.
For example, if a construction worker is exposed to bright
sunlight every day for long periods of time, “darkness
adaptation” deteriorates. If over-exposure to bright sunlight
continues for approximately ten days it will impair “dark
adaptation” to such an extent that three or more days of
non exposure to the sun are required for the eyes to return
to normal. This loss of “dark adaptation” can be prevented
by wearing sunglasses that will only allow light
transmission levels between 12% and 30%.
So the best possible protection from bright sunlight and
UV radiation is provided by the use of sunglasses that
feature tinted polycarbonate lenses. All of PIP’s shaded
lens glasses feature 100% polycarbonate lenses that
allow transmission levels of 12%. |
