Color Blindness

How the Eye Works Rods, located in the peripheral retina, give us our night vision, but can not distinguish color. Cones, located in the center of the retina (called the macula), are not much good at night but do let us perceive color during daylight conditions. Each cone contains a light sensitive pigment which is sensitive over a range of wavelengths (each visible color is a different wavelength). http://colorvisiontesting.com/color2.htm

What is color Blindness? Genes contain the coding instructions for pigments in the cones, if the coding instructions are wrong, then the wrong pigments will be produced, and the cones will be sensitive to different wavelengths of light (resulting in a color deficiency). The colors that we see are completely dependent on the sensitivity ranges of those pigments. A mild color deficiency is present when one or more of the three cones light sensitive pigments are not quite right and their peak sensitivity is shifted A more severe color deficiency is present when one or more of the cones light sensitive pigments is really wrong 8% of men and 0.5% of women have a color vision deficiency.

Types of Color Blindness or Vision Deficiencies Trichromacy- Normal color vision uses all three types of light cones correctly. People with normal color vision are known as trichromats. Monochromasy - complete absence of any color sensation. Protanomaly- a reduced sensitivity to red light Deuteranomaly- a reduced sensitivity to green light and is the most common form of color blindness Tritanomaly- a reduced sensitivity to blue light and is extremely rare.

Normal Vision Deuteranopia Deuteranopes are more likely to confuse: reduced sensitivity to green light Deuteranopes are more likely to confuse: Mid-reds with mid-greens Blue-greens with grey and mid-pinks Bright greens with yellows Pale pinks with light grey Mid-reds with mid-brown Light blues with lilac

Normal Vision Protanopia Protanopes are more likely to confuse: reduced sensitivity to red light Protanopes are more likely to confuse: Black with many shades of red Dark brown with dark green, dark orange and dark red Some blues with some reds, purples and dark pinks Mid-greens with some oranges

Normal Vision Tritanopia reduced sensitivity to blue light The most common color confusions for tritanopes are light blues with greys, dark purples with black, mid-greens with blues and oranges with reds.

Normal Vision Monochromacy No visible color only shades of grey http://www.colourblindawareness.org/colour-blindness/types-of-colour-blindness/

Testing for Color Blindness Ishihara color blindness test only test for red and green color deficiencies http://www.color-blindness.com http://www.color-blindness.com/ishihara-38-plates-cvd-test/#prettyPhoto/0/