Normal colour vision occurs when white light, which contains within it all the colours of the rainbow, enters the eye. This light activates three kinds of photo pigments, one in each of the three photoreceptors sensitive to different parts of the visible spectrum: blue, green and red.
Most types of colour blindness occur when there is an excessive overlap of the M (green) and L (red) colour cones in the eye, causing distinct hues to become indistinguishable. As a result, the number of shades of colour a typical colour blind person can see may be reduced by as much as 90%.
Protans are people with protanomaly, a type of red-green colour blindness in which the red cones do not detect enough red and are too sensitive to greens, yellows, and oranges.
As a result, greens, yellows, oranges, reds, and browns may appear similar, especially in low light. It can also be difficult to tell the difference between blues and purples, or pinks and greys. Red and black might be hard to tell apart, especially when red text is against a black background.
Deutan colour blindness (also known as deuteranomaly) is a type of red-green colour blindnessin which the green cones in the eye detect too much red light and not enough green light.
As a result red, yellow, green, and brown can appear similar, especially in low light. It may also be difficult to tell the difference between blues and purples, or pinks and greys.
Colour blindness is not a singular condition. It encompasses a range of conditions, from mild to severe, that can cause each person to see colour differently. EnChroma glasses are designed to improve colour vision of people with Protanomaly and Deuteranomaly, which are forms of partial red-green colour blindness.
Enchroma lens technology increases contrast between the red and green colour signals, alleviating symptoms of colour blindness for a richer experience of the world.