Visual Pathway And Defects

Front 1

What is being seen in each step of the visual pathway?

Back 1

1) Optic Nerve - portion of left and right hemifield
2) optic chaism - nasal retinas cross which each see the contralateral peripheral visual feild
3) optic tract - contralateral visual hemifield (macula + that side and periphery)
4)LGN - contralateral visual hemifield
5) Meyer's loop - contralateral superior portion of the visual hemifield
5) parietal optical radiation - contralateral inferior portion of the visual hemifeild
6) cuneus gyrus - contralateral inferior visual hemifield with the macular region spared
7) lingual gyrus - contralateral superior region of the visual field with the macula spared

Front 2

What is it called when you get a visual field defect in the optic nerve?

Back 2

Monocular blindness

Front 3

What do you lose when you get a visual field defect in the optic nerve?

Back 3

blindness in one eye, nasal portion of contralateral field and temporal portion of ipsilateral field

Front 4

What do you call a visual defect that occurs in the optic chiasm?

Back 4

bitemporal heteronymous hemianopsia

Front 5

What do you lose when you have a visual defect in the optic chaism?

Back 5

bilateral periperhal vision lost

Front 6

What is it called when you have a defect in the optic tract?

Back 6

contralateral homonymous

Front 7

What do you lose/what do you see when you have a visual defect in the optic tract?

Back 7

-blindness in contralateral temporal visual field and ipsilateral nasal visual field
-complete loss of vision in affected region of binocular field
you lose the contralateral visual hemifeild. so if you have a lesion in the optic tract of the right eye you lose the left hemifield. so that means you lose the left side of your right visual field and the left side of your left visual field

Front 8

What do you call a defect in Meyer's loop?

Back 8

contralateral superior homonymous quadratanopsia

Front 9

What do you call a defect in the parietal portion of the optic radiations?

Back 9

contralateral inferior homonymous qaudratonopsia

Front 10

What do you call the defect in the cuneus gyrus?

Back 10

contralateral inferior qaudratanopsia with macular sparing

Front 11

What do you call the defect in the lingual gyrus?

Back 11

contralateral superior quadratanopsia with macular sparing

Front 12

What are the three reflexes associated with the near response?

Back 12

1) convergence
2) accomodation
3) pupillary constriction

Front 13

What is the mechanism of convergence?

Back 13

medial rectus muscles contract to move both eyes towards midline so image remains focused at fovea

Front 14

What is the mechanism of accomodation?

Back 14

lenses are thickened due to contraction of ciliary muscles to maintain a focused image

Front 15

What are the two nerves that mediate the corneal reflex?

Back 15

1)trigeminal nerve opthalmic divsion senses touch, etc
2) sensory cell body is in the trigeminal ganglion
3)synapses at spinal root and trigeminal nucleus
4) an interneuron travels to the motor nuclei of CN VII
5) efferent is dispatched to contract orbicularis oculi

Front 16

What is miosis?

Back 16

constriction of pupil

Front 17

What is myhydriasis?

Back 17

dilation of pupil

Front 18

What is the innervation of the pupillary light reflex?

Back 18

1) retinal ganglion cells project to pretectum
2) pretectum recieves projects from both eyes
3) pretectum projects to edinger westphal nucleus bilaterally
4) edingerwestphal contains preganglionic PS neurons that travel with occulomotor nerve
5) occulomotor nerve goes to ciliary ganglion and synapse
6) post ganglionics innervate ciliary and spinchter pupillae muscles

Front 19

What is the Argyll Robertson pupil?

Back 19

accomodate but do not react to light

Front 20

What are Adie's tonic pupils/Holme's Adies syndrome?

Back 20

tonically dilated pupil because damaged PS innervation of eye

Front 21

What is aniscoria?

Back 21

unequal pupils

Front 22

What is the consensual resposne?

Back 22

pupillary constriction of opposite unstimulated eye

Front 23

What do you use to test visual field?

Back 23

humphrey visual field test