Berkeley Firm Invents Glasses to Correct Color-blindness

AP Photo
The Associated Press
Newport Beach, CA

A Bay Area company named EnChroma has just released glasses that use multi-notched filters that for the first time can correct the red-green color blindness suffered by 8 percent of men and 0.5 percent of women of Northern European ancestry.

The usual cause for color-blindness is a development failure in one or more sets of the eye’s retinal cones that perceive color in light and transmit that information to the brain’s optic nerve. EnChroma’s Cx glasses are not a cure for color-blindness, but rather an optical assistive device to correct a deficiency in seeing certain colors.

Color blindness is called a sex-linked condition, because the genes that produce the eye’s photo-pigments are carried on X chromosomes. The malady is more prominent in males, because they only have one X chromosome. It is dramatically less prominent in women, because females have two X chromosomes and the right gene on either of a female’s X chromosome will develop the correct photo-pigments for normal color vision.

Photo-pigments are the light-absorbing molecules found in the 6 million retinal cone cells housed in each human eye. When these molecules absorb photons of light at certain wavelengths, they chemically transform to cause receptors in the cone cells to fire a nerve impulse and then quickly re-set to absorb more photons.

There are three distinct classes of cone cells; L-cones absorb mainly red light, M-cones absorb green light, and S-cones absorb blue light. EnChroma uses a class of lens filters that contain one or more sharp “cut-outs” in the visible light spectrum where the maximum overlap occurs between the red and green photo-pigments. Cx lenses drive a wedge between the L-cone and M-cone signals to the brain, improving the separation of their brain signals to improve color recognition.

Cx lenses were discovered by a fortuitous “accident” in the lab in 2005 when Don McPherson, Ph.D. noticed certain transformative properties on color appearance resulting from special lens formulas he had invented for laser surgery eye protection.

But when a color-blind doctor tried them on, the glasses fundamentally changed his vision by making colors much more distinct and vibrant. The friend was amazed that flowers, fabrics, food, and traffic signs tended to pop-out with a heightened intensity.

After McPherson received NIH grants to develop the Cx lens, he picked up venture capital backing to form EnChroma, Inc. and conducted clinical trials at UC Berkeley Labs and UC Davis.

EnChroma Cx patent pending glasses look like ordinary glasses and are available with three different tints for light intensity and using computer monitors. They come in 11 different aviator and wrap-around shapes. For non-corrective glasses are priced between $330 and $675. There is an additional charge for prescription lenses.