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Brain and Behavior Exam 2 > Lec 26 Visual System and Gaze Disorders > Flashcards

Lec 26 Visual System and Gaze Disorders Flashcards

1
Q

What are the 3 layers of the eye?

A

external: sclera and cornea
intermediate: iris, ciliary body, choroid
internal: retina

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2
Q

What is the iris?

A

circular pigmented membrane enclosing pupil

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3
Q

What is the ciliary body?

A

just beneath sclera + lateral to lens
makes aqueous humor
contains ciliary muscle that allows lens to change shape to focus

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4
Q

What is the choroid?

A

layer of connective tissue and blood vessels between sclera and retina
suplles nutrients to the eye

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5
Q

What are the three fluid compartments of the eye?

A
  • anterior and posterior chambers in front of lens [separated by iris]
  • vitreous body [between back of lens and retina, contains jelly-like substance
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6
Q

What do the anterior/posterior chambers of eye contain?

A

aqueoue humor

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7
Q

What is an example of aqueous humor disorder?

A

glaucoma [excess aqueous humor in eye from drainage obstruction and other causes]

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8
Q

What is the lens?

A

biconvex structure, refracts light to focus it on retina

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9
Q

What is blood supply to lens?

A

avascular

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10
Q

What suspends the lens? what happens to these over time?

A
  • zonules

- they weaken with advanced age which is what causes eye problems as you get older

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11
Q

What are two examples of lens disorders?

A

presbyopia

cataracts

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12
Q

what is presbyopia?

A

loss of ability of lens to change shape [focus between distance and near]

– occurs with age, lens hardens and less elastic

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13
Q

what are cataracts?

A

clouding/yellowing of lens with advanced age

- initially have mild disturbance of vision then progressive loss

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14
Q

What is glaucoma?

A

excess aqueous humor (over production, under drain)

causes increased pressure thus lead to optic nerve injury and decreased vision

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15
Q

What are clinical signs of glaucoma?

A
  • high IOP
  • cupping of optic nerve
  • peripheral visual field loss progressing inward
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16
Q

What are two types of glaucoma?

A
  • primary open angle

- closed angle

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17
Q

What is primary open angle glaucoma?

A
  • wide/open angle betwen iris and cornea
  • due to slow clogging of drainage canals of eye
  • asymptomatic early but can advance to irreversible vision loss
  • most common type in elderly
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18
Q

What is closed angle glaucoma?

A
  • less common
  • higher risk in asians, females, hyperopia
  • angle/drainage canal between iris + cornea closed or narrow
  • creates suddent rise in IOP –> need meds or laser surgery
  • signs: ocular pain, redness, N/V, headche, blurred vision, halos around light
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19
Q

What is age-related macular degeneration [ARMD]? risk factors?

A

ARMD = degenerative disease of macula/fovea –> get decreased central vision/blind spot

risk factors: age > 70, fair skin, family history, smoking, heart disease

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20
Q

What are the two types of ARMD?

A
  • wet and dry
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21
Q

What is dry ARMD? signs?

A
  • gradual visual loss due to formation of small yellow deposits under macula
  • early = asymptomatic, straight lines appear crooked, advanced = central blind spot
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22
Q

What are drusen?

A

small yellow deposits under macula, cause dry ARMD

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23
Q

What is wet ARMD?

A
  • sudden, severe visual loss due to growth of blood vessels + bleeding under retina

decrease risk: eat fruits/veggies

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24
Q

What is diabetic retinopathy?

A
  • increased blood glucose damages retinal capillaries –> breakdown blood retinal barrier
  • causes retinal ischemia
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25
what are findings of diabetic retinopathy?
- early = asymptomatic - may have microaneurysms, hard exudates, intraretinal hemmorrhage - cotton wool spots - retinal ischemia
26
what are the 3 clinical stages of diabetic retinopathy
non-proliferative: asymptomatic pre-proliferative: give laser therapy to prevent long term vision loss proliferative: major cause severe visual loss, need laser treat or surgery
27
what is treatment for severe diabetic retinopathy? side effects?
- kill off peripheral ganglion skills to prevent VEGF from forming - laser treatment (causes some loss of peripheral vision and decreased night vision)
28
How does hyperglycemia affect eyes?
when blood glucose > 200, lens can swell in eye and lead to blurred vision
29
How does retinal detachment present?
- presents with: light flashes due to tugging of vitreous on retina, floaters, curtain over vision, can create whole in retina - usually have symptoms before retinal detachment
30
What is a retinal infarct? signs?
central retinal artery occlusion --> see retinal whitening/edema and cherry red spot in the middle if not treated w/in 3 hrs --> permanent vision lost
31
What is hollenhorst plaque?
thromboembolus in retinal arteriole
32
what is retinitis pigmentosa? signs?
- disorder of rods that involves progressive retinal degeneration due to pigmentary depositis - also see optic nerve atrophy - symptoms: nigh/low vision blindness, tunnel vision - slow process takes decade to happen - may be hereditary
33
What is a roth spot? what 2 systemic diagnoses should you consider?
- retinal hemorrhage with white center - infective endocarditis - leukemia
34
What covers the optic nerve?
meninges! because its just an extension of the CNS
35
What is optic neuritis? pathogenesis?
- inflammatory optic neuropathy | - presumed to be due to demyelination
36
What disease are associated with optic neuritis?
- multiple sclerosis - sarcoidosis - neuromyelitis optica - infections
37
Who gets optic neuritis?
usually under age 40
38
What are symptoms of otpic neuritis?
- acute onset: unilateral loss of visual acuity, color, field - pain on eye movement - may or may not have afferent pupillary defect [APD] - on exam: optic nerve head swollen or normal - visual loss worst days - 2 wks after onset, recover over wks - months
39
24 yo comes in with blurry vision, one eye really hurts with movement?
think optic neuritis!
40
What is treatment optic neuritis typically?
- can resolve on its own after wks to months - to accelerate: give IV steroids - give MRI since there is an association with MS
41
What is typical of MS on MRI of brain?
white matter periventricular lesions > 3mm in size
42
What is risk of MS with optic neuritis?
22% | or 72% if any sort of periventricular white matter lesion
43
What is papilledema?
optic disc edema/swelling caused by high intracranial pressure, usually bilateral - optic disc edema without ICP is not papilledema
44
What are causes of bilateral optic disc edema?
- papilledema - malignant hypertension - ischemia/inflamation, etc
45
What are causes of papilledema?
- intracranial mass [frontal lobe meningioma - hydrocephalus - pseudotumor cerebri
46
What is mech of optic disc edema?
lack of axonal transport from build up of pressure greater than IOP --> get disc swelling
47
What are symptoms of papilledema?
- many nerve axons lost before any detectable visual field defect - once visual loss begins, rapidly progresses - get chronic to atrophic papilledema within 3 wks
48
Which muscle contraction leads to miosis? which mydriasis?
sphinter = miosis [PNS] | dilator muscle = mydriasis [SNS]
49
What is physiologic anisocoria?
unequal pupil size
50
what is relative afferent pupillary defec [APD]t? test?
- defect = if input from one eye is less than the other | - swinging flashlight test --> input from one eye is less than other eye
51
causes of APD?
- optic neuritis/glaucoma - chiasmal or optic tract lesion - severe retinal damage - amaurotic pupil NOT: ocular media opacities [cataract] or amblyopia
52
What is Holmes-Adie's Tonic Pupil?
- idiopathic | - one pupil abnormally large --> constricts poorly to light, due to palsy of iris sphincter muscle
53
What is horner syndrome? signs?
oculosympathetic paralysis on one side - could indicate dissection of carotid artery signs: - ptosis and small pupil on one side - anhidrosis [decreased sweating] of the affected forehead - enesecoria worse in the dark [eye doesn't dilate in the dark]
54
who is at risk for glaucoma?
- elderly - afica americans - people with elevated intraocular pressure - family history of glaucoma
55
What should you think if pt presents with: gradual vision loss startig at periphery and progressing in?
glaucoma = tunnel vision
56
What should you think it pt presents with: vision loss starting with central blind spot in elderly
age-related macular degenration [ARMD]
57
What should you think: pt says straight lines appear crooked?
dry ARMD
58
Is dry or wet ARMD more gradual?
dry!
59
Should type 1 or type 2 diabetes have annual opthalmologic exams immediately after diagnosis?
type 2 because its likely they were undetected or had high blood glucose for a while
60
What is leading cause of blindness in working age americans?
diabetic retinopathy
61
What are argyll robertson pupils?
- bilateral - dissociation of light-near reflexes - irregular pupils, accomodate [constrict in near] but don't react [constrict in lihgt]
62
What are some possible common causes of argyll robertson?
- neurosyphilis | - diabetes
63
What are signs of pupil defect associated with 3rd nerve palsy?
- mydriasis [dilation] - ptosis - can't react to light or near
64
What is common cause of CN3 pupil lesion? why is pupil vulnerable?
- fibers to pupil are external part of nerve = vulnerable to compression - common cause = aneurysm of posterior communicating artery (Pcom)

Brain and Behavior Exam 2 (21 decks)

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