1. Colorblindness What causes it, and what it’s like to have it

2. Types of Cones There are 3 types of cones in the human retina There are 3 types of cones in the human retina Name of ConeMain wavelength it receives Main color it receives Short (S)420–440 nmBlue Medium (M)534–545 nmGreen Long (L)564–580 nmYellow

3. How you see color Light passes through your cornea and lens and hits the retina Light passes through your cornea and lens and hits the retina Long wavelengths excited the L cones, short the S cones, etc. Long wavelengths excited the L cones, short the S cones, etc. Your brain determines which cone is excited the most to determine which color you are seeing Your brain determines which cone is excited the most to determine which color you are seeing For example: For example: Mostly S and a little M= Blue Mostly S and a little M= Blue Only S= violet Only S= violet Only L= red Only L= red Mostly L and some M = yellow Mostly L and some M = yellow

4. Types of Colorblindness What do you think you could see if you only had S cones? What do you think you could see if you only had S cones? What if you only had M and L cones? What if you only had M and L cones? What if your M cones only worked in the very center of their spectrum and not the whole thing? What if your M cones only worked in the very center of their spectrum and not the whole thing?

5. Colorblindness tests! a.b.b. c.c.

6. Colorblindness tests! e.e. f.f. d.d.

7. Types of Colorblindness Con’t Monochromacy- when 2-3 types of cones are missing or non-functioning Monochromacy- when 2-3 types of cones are missing or non-functioning Things are in shades of grey, white, and black. Things are in shades of grey, white, and black. Very rare form of colorblindness Very rare form of colorblindness

8. Types of Colorblindness Con’t Protonopia- missing the L cones (to see red) Protonopia- missing the L cones (to see red) Can’t see the difference between red and green Can’t see the difference between red and green Occurs in 1% of males (sex- linked gene) Occurs in 1% of males (sex- linked gene)

9. Types of Colorblindness Con’t Deuteronopia- M cones are missing or broken (to see green) Deuteronopia- M cones are missing or broken (to see green) Can tell the difference between red or green Can tell the difference between red or green Also sex-linked affecting 5% of males (most common type) Also sex-linked affecting 5% of males (most common type)

10. Types of Colorblindness Con’t Tritanopia- missing S cones (for blue and violet) Tritanopia- missing S cones (for blue and violet) Hard to distinguish blue- green-yellow colors Hard to distinguish blue- green-yellow colors Very rare, hereditary form of colorblindness (not sex- linked) Very rare, hereditary form of colorblindness (not sex- linked)