Colour Blindness

                       Color Blindness

What is Color Blindness

Color blindness is the inability to differentiate certain colors. It comes in various flavours with the most common being red green color blindness. There are multiple causes, but color blindness is primarily inherited by way of a mutated X Chromosome. Due to the fact that men only have one X chromosome, if they are handed a faulty X chromosome (by a carrier mother) they will be color blind. Women on the other hand have two X chromosomes, which is why many less women are color blind than men.  The odds that both X chromosomes are faulty is extremely low, and the healthy one will take precedence providing normal perception of color.

Being color blind is officially considered a disability, however there have been studies documenting certain advantages including penetrating some camouflages. For instance – it was found during World War II that analysis of aerial photos yielded better results if at least one member of the surveillance team was color blind. It has also been suggested that females with one mutated X chromosome may be afforded an extra dimension of color awareness as they may have at least four types of cones in their eyes rather than two.

What Causes Color Blindness

Color Blindness is most commonly the result of hereditary reception of a genetically defective X chromosome. The chromosome usually comes from a carrier mother, and has a 50% chance of being passed to her son. A daughter of the same mother will have a 50% chance of also becoming a carrier, and is only likely at risk of becoming color blind if the father is color blind.

Color blindness can also be caused by accidents and other head trauma where permanent damage to the eyes occurs. This can happen as a baby (Shaken Baby Syndrome), or also later in life. UV Rays also present a risk of becoming color blind; they are in fact the leading cause of normal eye blindness in the world.

The 3rd way to get color blindness is through other hereditary diseases such as Diabetes. The list of diseases is long, and you can see the full list on the ‘Causes’ Page in the menu to the left. It should be noted that the amount of documented cases on these illnesses causing color blindness is limited, and as such the validity of these claims may be questionable.

Common Types of Color Blindness

Color blindness comes in the following types:

• Red Green Color Blind(most common)
  • Dichromacy (protanopia and deuteranopia)
  • Anomalous trichromacy (protanomaly and deuteranomaly)
• Blue Yellow Color Blind
  • Dichromacy (tritanopia)
  • Anomalous trichromacy (tritanomaly)
• Total Color Blindness (least common)

You can read the How it Works (science) page to understand what each of the scientific terms above means. Fortunately, green deficiency, which is arguably the mildest type is also the most common type of color blindness. However second most common is the total inability to see red. To really understand what this means to someone to live with this condition compare the following two images. You might feel sorry for anyone you know with this condition – given the amount of color they don’t get to see, but remember that they were born this way and don’t know the world to look any different.

The most common type of color blindness is red green color blindness, this type affects about 95% of all color blind people. The remaining 5% is made up of blue yellow color blindness, and less commonly – total color blindness. Within each color deficiency is the possibility of being either partially blind to that color, or totally. For example green deficient is more common, but being totally unable to see red is second most common.

Testing for Color blindness

The most common way to test for color blindness is known as the Ishihara Color Test. Dr Shinobu Ishihara, a University of Tokyo professor, created a series of plates to be used to identify red green color blindness. As you see in the image below, they contain a series of 38 plates; however an issue is normally well apparent after only a few. Testing all 38 plates will help to determine the level of severity of the sufferer. We have prepared a color blindness testusing these Ishihara test plates which you can access at any time via the left hand menu if you think that you, or someone you know, might be color blind – or just for fun!

Living with Color Blindness

Living with color blindness can be anything from trivial to frustrating, and sometimes even dangerous. Some people go their entire lives not knowing they were actually mildly color blind, whereas some are reminded daily of the inconveniences and risks of their disability.

Reminders come in the form of not knowing whether you’re looking at a stop or go traffic light, not knowing if your steak is cooked, or whether or not the tomato you wanted to use is ripe or not. But for some perhaps the biggest frustration is not being able to pursue the career you always dreamt of. Many arts based careers such as design can be nearly impossible for those with color blindness, while some such as being an air force pilot simply aren’t allowed.