FE: Lecture 8: Visual Flashcards
What makes up anterior and posterior part of eye?
cornea which contains aqueous humor
iris muscle and pupil
lens and ciliary muscle
What is in the vitreous chamber?
vitreous humor
retina(optic disk and nerve)
fovea and maccula
What are the layers of the retina?
- nucleus and plexiform layers
- receptor layer- rods, cones and pigmented epithelial
- bipolar cell layers- use local potentials to go to ganglion cells
- ganglion cell layers- projects to thalamus and superior colliculus
What do the rods do best in regards to vision?
they are more sensitive to light but have low amplitude threshold
do not distinguish light but have better sense of acuity
What do cones do best in regards to vision?
higher amplitude required, detects color/frequency and wave length of light
color blindness is lack of cones
What does RBG and LMS mean?
red (low frequency) green blue (high frequency)
long medium short
What is the definition of acuity?
ability to resolve small details, depends on number of receptors
What comprises the central retina?
the macula and fovea- central 10 degrees a huge number of cones and rods
What comprises peripheral retina?
few rods and cones
Where is color vision best in?
central retina
Where is acuity in normal light best in?
central
Where is acuity from low light best in?
just outside central
What does the brain need to do for best acuity?
it must aim the fovea at whatever it needs to see for high acuity
Where is the head of the optic nerve?
nasal retina
Where is your blind spot?
temporal visual field
What is the pathway of conscious vision?
Retina to lateral geniculate nucleus via optic nerve and tract
then LGN to primary visual cortex V1
What is pathway of unconscious vision?
Retina to tectum via optic nerve and tract
superior colliculus- optokinetic reflex
pretectal area- pupil constriction
Do ganglia neurons in nasal retina cross?
Yes at midline to LGN
Do ganglia in temporal retina cross?
No
Where does the right visual field of the left eye transmit to?
left visual cortex
Where does the right visual field of the right eye transmit to?
left visual cortex
Where do inferior and superior visual fields transmit to?
inferior VF to superior V1 cortex
superior VF to inferior V1 cortex
the macula goes to posterior cortex
If there is a monocular scotoma in the right eye nasal field where would damage be for you not to see?
temporal retina
If you had damage to right eye nasal and temporal field what would be damage ?
right optic nerve
If the temporal fields of both eyes are damaged what is leading to loss of vision?
optic chaism
If there is loss of vision in both left visual fields of both eyes why can’t you see?
damage to right optic tract, LGN or optic radiations
If you can’t see in both left visual fields except for macula what is the reason?
right visual cortex, partial lesion
What is pathway of pupillary reflex?
- light into eye then optic nerve to pretectal nucleus
- pretectal nucleus to EWN
- Oculomotor nerve to ciliary ganglia (parasympathetic)
- both pupils constrict bc it goes to both EWN via posterior commissure
Do you need the visual cortex for this reflex?
No
