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Sports Lenses 201

symptoms and prevent diseases, it has been found necessary to have a
standard method to test the colour preference in general practice. Research
in the field of sportvision has already established the merits of Eyebright
Test. The tint that is being preferred in the aforesaid test is the summation
of psychological as well as its physical properties. It may not be duplicated
in the spectacle, but is the guide to the practitioner to decide final
prescription on clinical judgments based on their optical principle and
degree of light sensitivity. Commonly LT 80% is the first choice for indoors
and LT 20% for sun. The important thing is that tints are not occupation
specific, they are person specific. Hence, the results of the Eyebright test
are very important. However, considering the environmental conditions
needed for different sports a general guideline can be worked upon what
tints have been seen to be most effective in different sports:

Orange: In normal use, orange is the essence of brown, so a tint diagnosis of
orange would translate to brown tint. Using clinical judgments, this would
be given indoors or outdoors at appropriate transmission level. Orange is
the most commonly used tint for clay shooting. They are good to enhance
visual performance and comfort, shooting sports require lenses that increase
visibility of targets, dampen backgrounds, ease eyestrain and fatigue, and
provide protection from harmful sunlight. Hunters and other target shooters
also benefit from orange tint.

Green: The diagnostic green is not usually prescribed unless for a specific
purpose. It makes a very good sunglass tint, because of its contrast
enhancing properties and good UV absorption. Green is also good IR
absorber. Golfers rely heavily on green filter to distinguish the ball from
green.
Blue: In particularly light sensitive subjects, the light scattering effect of
blue is outweighed by the relief they get from the elimination of peak
sensitivity wavelengths of yellow and orange. However, blue is absolutely
contraindicated for outdoor use because of the danger of high energy blue
light intensified by the brilliance of sun.
Yellow: A yellow filter increases the contrast between that colour and
surrounding colours, and concentrates light in the area of the spectrum to
which the eye is most sensitive. If an individual is already light sensitive
then the experience is heightened looking through a yellow or orange filter.
Contrast is also enhanced by its absorption of blue and UV, which makes it
effective for night driving against oncoming headlights and in fog. In fading
light , sports players may appreciate the effect on contrast. It is not suitable
as a sun spectacle because of glare and toxic effect of light at peak spectral
sensitivity. Hunters, pilots, shooters and tennis players find them helpful
for this purpose.