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Tinted Lens 83

Fig. 7.14: Blue –violet light hazards

Fig. 7.15: Corning CPF lenses

atmosphere. We are left with visible light. In the recent past studies have
been done to examine the effect of blue – violet end of the visible spectrum.
Although, they do not cause severe damage to the eyes, they do desensitize
the eyes to light. The nature of blue light is such that they are randomly
diffused, both in the atmosphere and within the human eyes. Rather than
reaching to a focus on the retina, blue light spreads in the whole interior of
the eye, causing dazzle. This phenomenon may not trouble the normal,
healthy eyes, but may affect severely where pathologies like cataracts,
diabetic retinopathy, macular degeneration, retinitis pigmentosa, corneal
dystrophy, albinism, aniridia and glaucoma are present. The contrast may
reduce and the objects may appear flat and washed out. Not only outdoors,
blue light is present indoors, in fluorescent tubes, television or computer
screens. Specially –designed lenses are needed to combat its adverse effects.
Corning has introduced a range of CPF photochromic filters. They include
CPF 450, CPF 511, CPF 527, CPF 550 and others. They have varieties of
applications and can be used indoors as well as outdoors.