PSY 162 Lecture Notes - Lecture 2: Visual Acuity, Color Blindness, Achromatopsia
(01/24/18)
Do You See Red the Way I See Red?
● In many ways this is not an answerable question
- we all have the same retinal circuitry -kinda- (arm grab analogy)
● Also we all have different experiences and we know learning influences perceptions
● Are these differences meaningful
Why??? (The dress)
Types of Color Deficiency
● Monochromat
- Only perceives intensity
- Can match a color to a test w/only 1 WL
● Dichromate
- Need 2 WL to match colors
● Anomalous Trichromate
- Needs 3 WL but uses them in different proportions
- Not as good a “normals” discriminating close colors
● Unilateral Dichromate
- 3 WL in 1 eye & 2 WLS in the other eye
● Cerebral Achromatopsia
- Color blindness due to damage to the cortex
Color Experience for Monochromes
● A very rare hereditary condition
● Only rods
- No function cones
● Perceive only white, gray, and black tones
- True color-blindness
● Poor visual acuity
● Eyes are very sensitive to bright light
Dichromates
● 3 Types
● Protanopia Affects 1% of males and .02% of females
- See short-wavelengths as blue
- Neutral point occurs @ 492Nm
- Above neutral point, they see yellow
- they are missing the long-wavelength pigment
-”Red” cones are filled w/”green” pigment
● Deuteranopia Affects 1% of males and .01% of females
- See short-wavelengths as blue
- Neutral point occurs at 498Nm
- Above neutral point, they see yellow
find more resources at oneclass.com
find more resources at oneclass.com
