human eye is most sensitive to light in the middle of the spectral range.
(500 to 550 nanometers). This approximates to green/yellow light.
Short wavelength light is the hardest portion of the spectrum for the human eye. Each photon of blue light (between 400 and 500nm) has a greater energy level associated with it than those of the longer wavelengths of the visible spectrum. In the ultraviolet region below 400nm, the energy levels of the photons are high enough to cause chemical changes. (For instance, sunburn, or cataracts). For this reason, the human eye has greater difficulty with blue light than any other color.
COLORED LENSES FOR SPECIAL APPLICATIONS
BPI® Filter Vision 450. This lens has a strong yellow color. The effect is to make everything brighter and in sharper focus. Because the eye focuses different colors in different places, eliminating portions of the spectrum allows the eye to focus more sharply. The increased visibility is because the yellow color is in the portion of spectrum that is most comfortable for the eye. The lens has applications in sports, shooting, driving and at times of low visibility.
Blue Barrier lenses. Blue light is the dominant component of skylight and a major cause of glare. Aging and a number of ocular conditions can make eyes extremely sensitive to what is normally seen as moderate glare, and these same pathological conditions also increase the possibility of veiling glare caused by blue light scatter within the eye. BPI® Blue Barrier lenses are available in orange, brown and red tints.
Violet/purple lenses. These colors have the characteristic of darkening green colors while increasing the brightness of reds, yellows and blues. They have applications in sports like golf where the white ball is highlighted against the fairway. Deep shades of purple are used to detect diseases and other problems in plant life. See BPI® Gardeners Glasses.
BPI Sports Tints. Designed for specific sporting events with color characteristics that increase visual acuity for sports participants. See BPI® Sports Tints.
BPI EVA lenses. Lightly tinted shades of yellow and brown that reduce glare and reflections by selectively passing colors while partially blocking portions of the spectrum that cause eye strain. (Specifically blue). See BPI® EVA® lenses.