How to Tell If Your Child is Colorblind
The most common form of colorblindness is also the least severe; anomalous trichromasy is represented by an ability to see all of the colors, but pigmented differently. It is caused by a weakness in the cones that normally perceive red or green – and sometimes both. Colors to someone with anomalous trichromasy are either more exaggerated toward reds, or towards greens.
Someone who is colorblind with anomalous trichromasy, with a green weakness, will have problems determining differences in the red spectrum. Oranges, Reds and Purples all seem similar. Someone colorblind with a slight red weakness will see yellows, reds, and greens as somewhat greener. Colorblind persons of this type are perfectly capable of passing their entire lives without realizing they have a deficiency of any type, and without ever making it apparent to their friends and relatives that they have a problem – because, essentially, they don’t. Unless they’re called on to name different hues of paint by sight.
Statistics show that Dichromasy is a more common ailment, but this form of colorblindness is far easier to detect, and therefore may seem more prominent than anomalous trichromasy simply because it has a bigger impact on people’s lives, and thus is easier to detect. Dichromatic Protanopia (Red Colorblindness) is the total or significant lack of red sensitivity. They are generally able to identify red, and various shades of red because of their brightness, or lack of brightness. A dichromatic protanope will perceive a red stoplight as a broken light; an American stop sign as white text against a very light gray. The nature of the red light spectrum causes a dichromatic protanope to perceive any red lighting as dimmed, or even entirely black. This especially becomes a problem when a blinking red traffic light is placed to signify traffic or road problems.
Red Colorblindness also causes an inability to distinguish purples from blues, which (from my personal experience) leads to friends and family members openly preventing the afflicted from purchasing their own clothing. In children, this form colorblindness can have a dramatic effect on their self-esteem, particularly when they are called on to identify colors. The Dichromatic Protanope perceives the world much like a cat; in shades of blue and yellow.
Dichromatic Deuteranopia (Green Colorblindness) is similar to its red-weak cousin, except that it does not come with the sensation of dimness. The Dichromatic Deuteranope sees the world in shades of orange and blue.
Identify Dichromatic Colorblindness
It is easy for a frustrated teacher to misidentify the signs of colorblindness, and just as easy for a parent to mistake the same signs for a learning disability.
Signs of Colorblindness:
Your child, when asked to dress himself (and colorblindness is far more prominent in males) often selects horrible clashes of red and purple. (The purple appears to us as a pleasing shade of blue while the red looks black or gray.)
Your child is reluctant to identify colors.
Your child is particularly slow in learning the difference between yellow and green, red and orange, blue and purple, etc.
Your child has difficulty seeing a white or yellow boundary line painted over grass (during kickball, softball, or other sports.)
Your child selects strange colors to represent firetrucks, fleshtones, and other common symbols in their artwork.
Your child’s teacher reports that he has a learning disorder, and much of his homework involves brightly colored paper and “fun” colored text.
Your child can see and read most things fine, but has problems reading text on a green chalkboard.
How to Test if your Child is Colorblind
Many (in fact most) eye exams do not include a color test. You must request such a test specifically from an eye doctor. You can also, to a more limited degree, test for colorblindness at home.
The Ishihara Test for Color Blindness:
http://www.toledo-bend.com/colorblind/Ishihara.html
The Waggoner Color Deficiency:
http://colorvisiontesting.com/online%20test.htm
A cool combination of both colorblindness tests:
