Around the world, nearly 300 million people (about one in 20) are colorblind. The colorful world is gray in their eyes, the difference is only the degree and type of color blindness. Some patients only know that they are color blind, but do not know what type; Some people with mild symptoms may not even know they are color blind.
Covisn, a company based in Hong Kong, has created color blindness corrective glasses that it hopes will help people with color blindness see the world in full color. The glasses use a “digital color enhancement” system. The system is mounted on the glasses and can perform the function of accurate shearing spectrum. By removing the primary color light wave in the spectrum, the overlapping part of the spectrum in the red-green vision disorder is filtered out, so as to improve the color vision experience of the patients with color blindness. Users say color discrimination is faster and more accurate after wearing the glasses, and they can now see more vivid colors.
For the vast majority of people, the world is as colorful as the often visible beauty of the scenery, is a gift of nature. But for the nearly 300 million people around the world who are colorblind, the world seems to have been rinsed, making it difficult for them to perceive the colorful world.
The reason why patients with red-green color blindness cannot distinguish red from green is the abnormal Spectral Overlap of their red and green photoreceptors, which is caused by the way photoreceptors absorb light.
There are usually three different types of cones in the human retina: one that absorbs mainly red light (called L-cones), one that absorbs mainly green light (M-cones), and one that absorbs blue light (S-cones). It is not that most color blindness lacks one of these photoreceptors, but that the spectrum experienced by the M-type variant has shifted so much that it overlapped with the L-type that it cannot be distinguished well. When stimulated with a red light, the cones, which are responsible for green color, also responded, causing the sensory abnormality
▲ On the left, a color-blind man wearing color blind glasses sees Venice. On the right, a color-blind person sees Venice. Spectral frequency response of cones in the right figure is abnormal, resulting in spectral overlap.
To allow users to better distinguish between red and green light, the EnChroma glasses team first built a sophisticated computer model that mimics the types and extent of defects in color perception, using the latest theories on the genetic basis of color blindness and the known mechanisms of aberrant spectral variation.
By applying a large number of simulation techniques to the optical filter, the lens becomes a multistage filter with a specific spectral transmittance function, and the part that is filtered by this filter happens to be the part with the greatest spectral overlap in red-green vision impairment. By effectively cutting or increasing the signal difference between the L-cone and the M-cone, the improved signal separation ultimately provides a better color vision experience for people with color blindness.
Structure of Covisn lens
It has a certain auxiliary effect on people with color deficiency (about 75% of all people with color blindness), but it is ineffective for people with full color blindness who are missing a kind of photoreceptor (protanopia, deuteranopia, tritanopia).