Different types of colour blindness
19 April 2022
What is colour blindness?
Colour blindness, also known as colour vision deficiency, is a common medical condition in which a patient has difficulty distinguishing between certain colours. This condition can be passed on through genes at birth or acquired later due to age, eye injury, eye disease, chemical toxicity, or certain medications. In this blog post, we will be looking at the different types of colour blindness, the side effects of each, and possible treatments.
Before we delve further into the different types of colour blindness, here’s a short explanation of how our eyes perceive colour.
Our eyes contain photoreceptors called rods and cones. Rods sense light and dark, while cones sense different wavelengths of light and are responsible for colour perception. Cones are divided into three categories:
- Red light (long wavelength)
- Green light (medium wavelength)
- Blue light (short wavelength)
A person with normal colour vision, also known trichromacy, has equal amounts of all three cones (hence the ‘tri’), whereas a person with colour blindness lacks all or some cones.
Types of colour blindness
1. Red-green colour blindness
This is the most common type of colour blindness. It makes it hard to tell the difference between red and green. People with red-green colour blindness fall into two main categories:
Protan types
These people have a deficiency in red cones and are further divided into protanopia and protanomaly. Protanopia means a complete absence of red cones. Protanomaly means the individual has a few red cones and can usually see some shades of red. However, red can look more like green to them and is less vibrant than it appears for a trichromat.
Deutan types
These people have a deficiency in green cones. Deuteranopic individuals have no green cones. Deuteranomaly, the most common type of red-green colour blindness, means that individuals still have some green cones and can see certain shades of green.
2. Blue-yellow colour blindness
Blue-yellow colour blindness is very rare and only occurs in 1 out of every 10,000 people. It makes it difficult to tell the difference between blue and green as well as yellow and red. There are two types of blue-yellow colour blindness:
Tritanomaly
While these individuals have blue cones and can see some shades of blue, their rainbows have greener blues, and there’s little to no yellow.
Tritanopia
This type of blue-yellow colour blindness means that you have no responsive blue cones.
3.Complete colour blindness
Individuals with monochromacy or complete colour blindness can’t see colours at all. This deficiency is very rare and, depending on the type, individuals may have trouble with their sight.
How does colour blindness affect your life?
While most people with colour blindness can see colour, their perception of colour is limited and inaccurate. If you are colour blind, you may find it difficult to shop for groceries, read charts and graphs, and dress in matching hues. As this condition affects your eyesight, you may also be unable to work in certain occupations, such as fashion styling or as a graphic designer.
Treatment options
If you suspect you have colour blindness, the first step is to visit your optician to receive a diagnosis. Once you have received a formal diagnosis, you can begin to investigate ways to make living with colour blindness easier.
Currently, there’s no effective treatment for inherited colour blindness. However, there are specialty lenses that enhance colour vision, which may reduce your symptoms and improve your perception between different hues.
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