The different anomalous condition types are protanomaly, which is a reduced sensitivity to red light, deuteranomaly which is a reduced sensitivity to green light (the most common form of colour blindness) and tritanomaly which is a reduced sensitivity to blue light (extremely rare).
Deuteranomaly is the most common type of color blindness, affecting about 6% of men. It is characterized by a reduced sensitivity to green light, making it difficult to differentiate between shades of red and green. Protan (“pro-tan”) is the second most common and is characterized by a reduced sensitivity to red light.
Rod monochromacy (Achromatopsia)
This is the rarest and most severe form of color blindness in which there are no functional cone cells with working photopigments. People with rod monochromacy can only see black, white, and gray.
Females inherit one X chromosome from each parent; hence they can be either homozygous or heterozygous. A color-blind girl is born only when her father is color blind, and her mother is a carrier. If the maternal grandfather is color blind, the mother will be a carrier.
Firstly, children with colour blindness can be considered to have both a Special Educational Need and to be disabled as they need extra support in many situations both at home and at school.
Instead, most people with color blindness see a limited range of colors. Red-green color blindness makes it hard to tell the difference between red and green. Blue-yellow color blindness is less common and makes it hard to distinguish between blue and green, yellow and red, and dark blue and black.
Inherited colorblindness — also called color vision deficiency — has no cure today. But for some people with milder forms of red-green colorblindness, specially formulated color-correcting eyeglasses may improve contrast between some colors.
People who are totally color deficient, a condition called achromatopsia, can only see things as black and white or in shades of gray. Color vision deficiency can range from mild to severe, depending on the cause. It affects both eyes if it is inherited and usually just one if it is caused by injury or illness.
People who are color blind see normally in other ways and can do normal things, such as drive. They just learn to respond to the way traffic signals light up, knowing that the red light is generally on top and green is on the bottom.
Cyanopsia is a medical term for seeing everything tinted with blue. It is also referred to as blue vision. Cyanopsia often occurs for a few days, weeks, or months after removal of a cataract from the eye. Cyanopsia also sometimes occurs as a side effect of taking sildenafil, tadalafil, or vardenafil.
About one in 12 men (8%) and one in 200 women (0.5%) have defective colour vision.
There are different degrees of color blindness. Some people with mild color deficiencies can see colors normally in good light but have difficulty in dim light. In contrast, others are unable to distinguish specific colors in any form of light.
The types of red-green color blindness fall into four different categories. Protanopia (aka red-blind) – Individuals have no red cones. Protanomaly (aka red-weak) – Individuals have red cones and can usually see some shades of red. Deuteranopia (aka green-blind) – Individuals have no green cones.
Deuteranopia/green-blind: With this type of color blindness, people aren't able to differentiate between red and green. Reds are often mistaken as brown/yellow and greens as beige.
The retina is covered with millions of light sensitive cells called rods and cones. When these cells detect light, they send signals to the brain. Cone cells help detect colors. Most people have three kinds of cone cells.
Mouse over this standard colorwheel to see it as a colorblind person might see it. Color vision deficient people have a tendency to better night vision and, in some situations, they can perceive variations in luminosity that color-sighted people could not.
The picture below shows that for all of the types of color blindness there is a pair of colors that can be distinguished – red and blue – these are color blind safe colors. As for the green, it is the number one among the colors to avoid for the color blind.
For example, blue/orange is a common colorblind friendly palette. Blue/red or blue/brown would also work (for most colorblind people blue would generally look blue). In the end, to make sure your design is colorblind friendly print it out in black and white or grayscale.
It also includes people who are colour blind or who use corrective devices such as reading glasses. The law applies to such people if they experience discrimination as a result of their impairment.
The life expectancy of a color-blind person is normal. There are no other abnormalities associated with the condition.