ColorblindneColorblindnessss

What causes it, and what What causes it, and what it’s like to have itit’s like to have it

Types of ConesTypes of Cones

There are 3 types of cones in the human There are 3 types of cones in the human retinaretina

Name of Cone

Main wavelength it receives

Main color it receives

Short (S) 420–440 nm Blue

Medium (M) 534–545 nm Green

Long (L) 564–580 nm Yellow

How you see colorHow you see color

Light passes through your cornea and lens and hits Light passes through your cornea and lens and hits the retinathe retina

Long wavelengths excited the L cones, short the S Long wavelengths excited the L cones, short the S cones, etc.cones, etc.

Your brain determines which cone is excited the Your brain determines which cone is excited the most to determine which color you are seeingmost to determine which color you are seeing

For example: For example: Mostly S and a little M= BlueMostly S and a little M= Blue Only S= violetOnly S= violet Only L= redOnly L= red Mostly L and some M = yellowMostly L and some M = yellow

Types of Types of ColorblindnessColorblindness

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

Colorblindness tests!Colorblindness tests!

a. b. c.

Colorblindness tests!Colorblindness tests!

e. f.d.

Types of Types of Colorblindness Con’tColorblindness Con’t

Monochromacy- Monochromacy- when 2-3 types of when 2-3 types of cones are missing or cones are missing or non-functioningnon-functioning

Things are in shades Things are in shades of grey, white, and of grey, white, and black.black.

Very rare form of Very rare form of colorblindnesscolorblindness

Types of Types of Colorblindness Con’tColorblindness Con’t

Protonopia- missing Protonopia- missing the L cones (to see the L cones (to see red)red)

Can’t see the Can’t see the difference between difference between red and greenred and green

Occurs in 1% of Occurs in 1% of males (sex-linked males (sex-linked gene)gene)

Types of Types of Colorblindness Con’tColorblindness Con’t

Deuteronopia- M Deuteronopia- M cones are missing or cones are missing or broken (to see green)broken (to see green)

Can tell the difference Can tell the difference between red or greenbetween red or green

Also sex-linked Also sex-linked affecting 5% of males affecting 5% of males (most common type)(most common type)

Types of Types of Colorblindness Con’tColorblindness Con’t

Tritanopia- missing S Tritanopia- missing S cones (for blue and cones (for blue and violet)violet)

Hard to distinguish Hard to distinguish blue-green-yellow blue-green-yellow colorscolors

Very rare, hereditary Very rare, hereditary form of form of colorblindness (not colorblindness (not sex-linked)sex-linked)