Visual System: Peripheral Flashcards
photons
discrete particles of energy that make up light
Waves
waves of energy = make up light
wavelength
the length of a wave = relates to which color we see
intensity
relates to how bright the light is
Visible light (humans)
380-760 nm
sensitivity
the ability to detect the presence of dimly lit objects
acuity
the ability to see the details in objects
depth of focus
the range of depths that can be kept in focus on the retina
decreases when it’s darker
Iris
the doughnut shaped bands of contractile tissue
gives the eye its color
pupil
the hole in the center of the iris that light enters through
size changes with differences in how light it is
lens
focuses light on the retina
ciliary muscles
muscles that alter the shape of the lens as needed
Accommodation
the process the ciliary muscles go through when adjusting the lens
Convergence
eyes must turn slightly inward when viewing objects
Binocular Disparity
The difference of position of the same image on both retinas (bc your eyes are on 2 different spots)
Retina
converts light to neural signals
receptors
first layer of retina (from the back of the eyeball)
horizontal cells
2nd layer of the retina (from the back of the eyeball)
bipolar cells
3rd layer of the retina (from back to front of the eyeball)
amacrine cells
4th layer of the retina (from back to front of the eyeball)
retinal-ganglion cells
5th layer of the retina (from the back to from of the eyeball)
fovea
an indentation at the center of the retina
-specialized for high acuity
blind spot
the spot in the retina w/ no receptors, where the optic nerves leave the eye
completion
the brain uses info from the receptors around the blind spot to fill in the gaps in the retina (blind spot)
duplex theory of vision
the idea that rods and cones mediate different types of vision
Rods
- high sensitivity (darkness)
- low acuity (bad quality of detail)
- don’t see color
- sensitive to shorter wavelengths*
Cones
- low sensitivity (don’t see well in the dark)
- high acuity (see details well)
- color
- sensitive to longer wavelengths*
Scoptic Vision
the vision controlled by rods (non-color, high sensitivity)
Photopic Vision
the vision controlled by cones (color, high acuity)
3 types of cones
red, green, blue
long WL, Medium WL, Short WL
Component theory
trichromatic
color is encoded by the ratio of activity in all 3 types of cones
Opponent-process theory
color is processed in an antagonistic manner
saccades
quick, involuntary, eye movements
they are summated over time, to make an image
