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“I’M BLIND! … Colour blind.” The Different Types of Colour Blindness

November 18th, 2014

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Simply put, color blindness is the inability or decreased ability to see color, or at least to differentiate varying colors. You mustn’t mistake it for blindness since someone afflicted with this disorder can still see clearly; he or she only has deficiency with color vision. And you ought to know that color blindness comes in different types, which will be discussed below. Using corrective lenses or even tinted sunglasses won’t remedy it; as of now, there is no known and proven treatment for color vision deficiency.

But first, let’s talk about how color vision works. The human eye normally has rods and cones, photoreceptors to help us perceive light and color. We have around 120 million rods which are sensitive to light and 6 to 7 million cones to help us perceive color. These cones are subdivided into three types: the S-cones for short wavelength light (for the color blue); the M-cone for medium wavelength light (for the color green); and the L-cone for large wavelength light (for the color red). All three cones must function together for us to perceive varying shades of colors.

So without further ado, let’s take a look at some types of color blindness:

pleasantville monochrome


This is the condition where an organism only has one type of cone cell for color vision, limiting its ability to perceive color. Though it’s more often found in animals, humans can sometimes be also afflicted. It has two types, Rod Monochomacy, wherein a person has no cone cell in the eye at all; and Cone Monochromacy, wherein a person has both rods and cones but only a single functioning cone. The best known disorder associated with monochromacy is Achromatopsia. People with this syndrome can only see things in black and white, and they also suffer from decreased visual acuity, iris operating abnormalities and other symptoms.


pleasantville colours 2


People with dichromacy only have two functioning cone cells. It is subdivided into three types: Tritanopia, where the patient can’t see blue due to missing or malfunctioning S-cones; Deuteranopia, where the patient can’t see green due to missing or malfunctioning M-cones; and Protanopia, where the patient can’t see red due to missing or malfunctioning L-cones. Each of these types disables a person’s ability to see one of the three primary colors or at least diminishes their ability to see that specific palette.


pleasantville colours

Anomalous Trichromacy

People with this type of color blindness have all three types of cones, but these cells don’t function perfectly. The sensitivity in one or two of the cones would increase from time to time, resulting in a vision somewhat similar to that of people with dichromacy. It is also subdivided into three types: Protanomaly, Deutranomaly, and Tritanomaly. Each of these represents the human eye’s complete or decreased ability to perceive red, green and blue respectively.


As mentioned earlier, there is still no known and proven cure for color blindness. If you suspect that you or a family member may be color blind, especially children, get a proper diagnosis from your trusted ophthalmologist immediately.


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