Orbit, Eye, & Vision Part 3 - Herring

Question 1

entire area of space that a person can see at a given moment

Answer 1

visual field

Question 2

the specific area on the
retina where light from
that part of the visual field is projected

essentially, where part of the visual field projects onto the actual retina

Answer 2

retinal field

Question 3

using 2 eyes at the same time to create a single image of the world

Answer 3

binocular vision

Question 4

2 visual fields for binocular vision, explain them and what the the area of overlap assists with

Answer 4

1 for the left eye

1 for the right eye

Area of overlap in the middle to assist with depth perception

Question 5

Visual field of each eye is divided into ________ and ________ regions

Answer 5

temporal (lateral) ; nasal (medial)

Question 6

Both temporal and nasal visual fields are further divided into _____ and ______ visual fields

Answer 6

superior ; inferior

Question 7

Ultimately ___ quadrants in each visual field

Answer 7

4

Question 8

Retina of each eye is also divided:

Temporal retina =

Answer 8

lateral retina

Question 9

Retina of each eye is also divided:

Nasal retina =

Answer 9

medial retina

Question 10

After passing through the lens, light from each portion of the visual field projects to the _______ side of the retina

Answer 10

opposite

Question 11

Visual world projects onto retina with a specific _______

Answer 11

orientation

Question 12

At the lens the image from the visual field/outside world is ______ and ________

Answer 12

inverted ; left/right reversed

Question 13

View of the right side of the “world” (right visual fields) represented on the :

Nasal retina of the ____ eye

Temporal retina of the ____ eye

Answer 13

right

left

Question 14

View of the left side of the “world” (left visual fields) represented on the :

Nasal retina of the ____ eye

Temporal retina of the ____ eye

Answer 14

left ; right

Question 15

Each optic nerve (CN II) then carries a “full” representation of the ____ & ____ sides of the world

Answer 15

right and left

Question 16

each optic nerve (CN II) carries the entire visual field for the _____ eye

Answer 16

ipsilateral

Question 17

Left optic nerve = carrying the left (temporal) visual field on _____ retina and right (nasal) visual field on ______ retina

Answer 17

nasal ; temporal

Question 18

Lesion of the optic nerve (CN II) = blindness from the ____ eye

Answer 18

SAME

Monocular vision loss!!

(loss of right & left sides of the visual fields from the ipsilateral retina)

Question 19

Optic Chiasm - “Peripheral vision” fibers / temporal visual fields ______

Answer 19

Cross / Decussate

Question 20

Optic Chiasm –> PERIPHERAL VISION - from the right optic nerve =

fibers from the nasal retina (carrying the view of the temporal visual field / “right side of the world”) ______

Answer 20

CROSS

Question 21

Optic Chiasm –> PERIPHERAL VISION - from the left optic nerve =

fibers from the nasal retina (carrying the view of the temporal visual field / “left side of the world”) ______

Answer 21

CROSS

Question 22

Optic Chiasm –> CENTRAL VISION - from the right optic nerve =

fibers from the temporal retina (carrying the view of the nasal visual field / “right side of the world”) do not _____

Answer 22

CROSS

Question 23

Optic Chiasm - “CENTRAL VISION” fibers do not ____

Answer 23

cross

Question 24

Optic Chiasm –> CENTRAL VISION - from the left optic nerve =

fibers from the temporal retina (carrying the view of the nasal visual field / “left side of the world”) do not _____

Answer 24

CROSS

Question 25

Lesion at the optic chiasm that only affects the middle (crossing / decussating) fibers =

Answer 25

tunnel vision (patient loses peripheral vision / temporal visual fields) BITEMPORAL HEMIANOPIA

Question 26

Lesion at the optic chiasm that affects all of the optic chiasm =

Answer 26

blindness from both eyes

Question 27

The optic tract extends from the optic chiasm to the ______ on each side

Answer 27

thalamus

Question 28

Each optic tract carries the visual field of the ______ side

Answer 28

opposite

Question 29

Optic Tract - Right optic tract carries _____ side of the “world” (visual field)

Answer 29

left

Question 30

Optic Tract - Left optic tract carries ___ side of the “world” (visual field)

Answer 30

right

Question 31

Lesion at the optic tract

Answer 31

Opposite side goes dark (Contralateral homonymous hemianopia) (a visual defect that causes loss of vision in the same half of the visual field in both eyes)

Question 32

Right optic tract lesion = loss of the ____ side of the visual field from ____ eyes

Answer 32

left ; both

Question 33

Left optic tract lesion = loss of the _____ side of the visual field from _____ eyes

Answer 33

right ; both

Question 34

Pathway of Vision Most fibers of each of the optic tracts then project to ________ in their ipsilateral lateral geniculate nucleus (LGN) of the ______

Answer 34

2nd order cell bodies thalamus

Question 35

Pathway of Vision Each lateral geniculate nucleus projects to its ___________

Answer 35

ipsilateral occipital cortex (primary visual cortex)

Question 36

Pathway of Vision Between lateral geniculate nucleus & the occipital cortex, the fibers carrying the upper and lower visual fields ______

Answer 36

separate

Question 37

Lesions between the lateral geniculate nucleus & the occipital cortex can result in losing a ________ of the visual field from ______ eyes

Answer 37

quadrant ; both

Question 38

Leading cause of severe vision loss in those >50 years (~10 million people in US)

Answer 38

Macular Degeneration

Question 39

Vision loss in the center of visual field

Answer 39

Macular Degeneration

Question 40

Damage to the cone-dense macular region of retina (trouble discerning colors) Blurry central vision that can progress to blind spot(s) in the central vision Peripheral vision remains

Answer 40

Macular Degeneration

Question 41

Progressive accumulation of protein deposits in the macula (~85% of cases) Deposits may further dry and thin macula which increases symptoms

Answer 41

Dry Macula Degeneration

Question 42

abnormal leakage of blood vessels deep to the macula causing fluid to build up & scar the macula

Answer 42

Wet Macular Degeneration

Question 43

Complication from diabetes affecting the blood vessels of retina

Answer 43

Diabetic Retinopathy

Question 44

Blood vessels weaken, bulge, or leak into retina due to high blood sugar levels Causes retina to swell, potential hemorrhages

Answer 44

Diabetic Retinopathy

Question 45

Early: changes in near or distant vision, blurry vision Later stages: dark eye floaters caused by leakage of blood or scarring of retina by the leaky vessels. New blood vessels grow on the retina (fragile & bleed into the vitreous body). Increased likelihood of retinal detachment

Answer 45

Diabetic Retinopathy

Question 46

Pupillary Light Reflex A smaller subset of fibers from the optic tracts project to their _____ pretectal nucleus

Answer 46

ipsilateral

Question 47

Pupillary Light Reflex Each pretectal nucleus projects _______ to the right & left Edinger-Westphal nucleus

Answer 47

bilaterally

Question 48

Pupillary Light Reflex Each Edinger-Westphal nucleus (preganglionic parasympathetic cell bodies) sends its axons peripherally as part of their

Answer 48

ipsilateral CN III (oculomotor nerve)

Question 49

Pupillary Light Reflex The preganglinic parasympathetic fibers of each CN III synapse on their IPSILATERAL __________

Answer 49

ciliary ganglion (postGPS cell bodies)

Question 50

Pupillary Light Reflex Postganglionic parasympathetic fibers “hitch-a-ride” on their ipsilateral _____________ nerves to pierce the ______ to the ________ and _________

Answer 50

short ciliary nerves ; eyeball ; constrictor pupillae & ciliary muscle

Question 51

Lesion to the optic nerve: Light shined in the ipsilateral pupil

Answer 51

Neither pupil constricts Brain does not know there is light projecting onto the retina

Question 52

Lesion to the optic nerve: Light shined in the contralateral pupil

Answer 52

Both pupils dilate Brain perceives there is light through the intact pupil No damage to parasympathetic (motor) pathways

Question 53

Lesion to the Edinger-Westphal nucleus, PreGPS fibers of CN III, ciliary ganglion, or postganglionic parasympathetic fibers (lesion to the motor component of the reflex): Ipsilateral pupil size does ____ change (does not constrict) when a light is projected into either eye

Answer 53

not No motor signal reaches the constrictor pupillae to tell it to constrict

Question 54

Lesion to the Edinger-Westphal nucleus, PreGPS fibers of CN III, ciliary ganglion, or postganglionic parasympathetic fibers (lesion to the motor component of the reflex): Contralateral pupil _____ when a light is projected into either eye

Answer 54

constricts Motor pathway intact so signal reaches the constrictor pupillae as expected

Question 55

Right optic tract - fibers from the temporal retina of the _____ eye & the nasal retina of the _____ eye

Answer 55

right ; left

Question 56

Left optic tract - fibers from the nasal retina of the _____ eye & the temporal retina of the _____ eye

Answer 56

right ; left