Vision Flashcards
amplitude
- height of wave
- higher is brighter
- lower is duller
wavelength
- higher wavelength is a lower frequency
- lower wavelength is a higher frequency
purity
impacts the % of saturation or richness of colours
pure light
light made up from one wave length
natural light
light made up of multiple wave lengths
lights trhough the eye
1) cornea
2) pupil
3) iris
4) lens
5) vitreous humour
6) retina
cornea
transparent window at front of the eye
responsible for ~80% of focusing power
pupil
round window in middle of eye (black dot)
iris
controls size of pupil
if dim out dilates
if bright out contracts
lens
final focusing of light
project image onto retina
is curved
curved lens
project image upside down and backwards onto retina, brain compensates
flexible lens
close object:lens get rounder
far object: lens elongates
vitreous humour
clear jelly
holds eye together
retina
made of 3 layer
1) photoreceptors
2 & 3) horizontal and amacrine cells
photoreceptors beside retinal pigment epithelium because it is its energy source
cones
6 million used for day vision allow to see colour good visual acuity concentrated toward fovea
rods
125 million periphery vision used for night vision provide no colour info poor visual acuity
neural signals pathway
photoreceptors > bipolar cells > ganglion cells
blind spot
due to lack of photo receptora on the optic disc
cones grouping
direct connection to brain
high visual acuity
rods grouping
less direct connection to brain
lower visual acuity
left brain gets infor from
right nasal retina
left temporal retina
right brain gets info from
left nasal retina
right temporal retina
main pathway
most axons synapse in the LGN
primary visual cortex
V1
in occipital lobe
extrastriate cortex
visual processing area in the occipital lobe
visual info pathway
ganglion to 1 LGN
many LGN to 1 V1 cell
dorsal stream
where
parietal
ventral stream
what
temporal
light sensitive path
jelly fish and worms
curved “cup” eye
allow direction of light to be sensed
crude lens
allowing input from stimulus from different distances
compound eye
good at detecting movement close up
simple eye
differ depending on enviroment
large eyes
can benefit eith acuity or night acuity
lateral eyes
prey
bad depth perception
forward eyes
predator
increased depth perception
eye development
2 month prenatul: eyes form
6 months prenatul: react to light
random firing determines how cells will connect
newborn: weak lens muscles
3 months old: almost adult like focus
11 years: visual brain area full developed
visual acuity development
birth (20/600)
6 months (20/100)
4-6 years (fully reach acuity)
man who only shaved half face, ate half plate of food
NOT VISUAL DEFECIT
attention issue
parietal lobe damage
brain assumes _____ light source
one
blind people can
still show emotional and action blind spot
sclera
a tough structural membrane that covers to portion of the eye not covered by the cornea
