Pupils Flashcards

1
Q

What are the 4 fundamental rules of pupils?

A
  1. Pupils are equal members of a team
  2. The pupil control system has two “managers”
  3. Pupils are subject to a near triad or synkinesis
  4. The pupils reflect the body in which they live
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2
Q

Pupils do what to allow better focus?

A

Constrict

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3
Q

How is pupillary constriction achieved?

A

By the pupillary light reflex

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4
Q

What percent of the population has physiological anisocoria?

A

20%

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5
Q

If anisocoria is physiological, does the level of illumination change the amount of anisocoria?

A

No

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6
Q

What are the two “pupil managers”?

A

Para-sympathetic system

Sympathetic system

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7
Q

What is the (pupil) target of the para-sympathetic system?

A

Iris sphincter

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8
Q

What is the neurotransmitter for the system responsible for miosis of the pupil?

A

Acetylcholine

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9
Q

What is the afferent pathway of the pupillary light reflex?

A

Light on the retina ->
Signals carried to the brain ->
About half of the fibers cross over at the optic chiasm ->
Pupil fibers leave the optic tract and enter the brachium of the superior colliculus->
Enter the pretectal nucleus in the midbrain

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10
Q

Which fibers cross over at the optic chiasm in the afferent pathway of the pupillary light reflex?

A

Nasal fibers

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11
Q

What is the efferent pathway of the pupillary light reflex?

A

Info starts at the pretectal nucleus ->
Goes to the Edinger-Westphal nuclei on both sides ->
Travels back to the eye along CN III ->
Fibers synapse at the ciliary ganglion ->
Destination is the iris sphincter

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12
Q

What are the neurotransmitters for the sympathetic system?

A

Preganglionic: acetylcholine
Postganglionic: norepeinephrine

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13
Q

What is the (pupil) target of the sympathetic system?

A

Iris dilator

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14
Q

If there is a lesion at the optic chiasm, what visual fields will be lost?

A

Temporal visual fields

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15
Q

If there is a lesion at the optic tract, what visual fields will be lost?

A

The same side in both eyes (Lesion on right side, lose temporal of left eye, medial of right)

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16
Q

If there is a lesion at the lateral geniculate nucleus, what visual fields are impaired?

A

The same side in both eyes (Lesion on right side, lose temporal of left eye, medial of right), but with macular sparing

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17
Q

Where is a 1st order lesion found in the sympathetic system to the eye?

A

Begins at hypothalamus, goes to the center of Budge (C8-T1,2)

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18
Q

What is the most likely cause of a 1st order lesion of the sympathetic pathway?

A

Cerebro-vascular accident

  • MS
  • Neck trauma
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19
Q

Where is a 2nd order lesion found in the sympathetic system to the eye?

A

Center of Bugde (C8-T1,2), jumps the apex of the lung, and goes to the cervical ganglion

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20
Q

What are the most likely causes of a 2nd order lesion of the sympathetic system to the eye?

A
Pancoast's tumor (smokers)
TB
Cancer
Trauma
Throid
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21
Q

Where is a 3rd order lesion found in the sympathetic system to the eye?

A

Cervical ganglion

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22
Q

What is the sympathetic pathway to the eye from the cervical ganglion?

A

Follows the internal carotid artery ->

Splits into nasociliary and ophthalmic artery branches

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23
Q

What is a lesion on the nasociliary branch of the sympathetic system to the eye probably caused by?

A

Aneurysm

Nasopharyngeal carcinoma

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24
Q

What is a lesion on the ophthalmic artery branch of the sympathetic system to the eye most likely caused by?

A

Migraines

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25
Q

What type of fibers make up the optic chiasm?

A

Nasal fibers only

26
Q

What is hippus?

A

The unstable equilibrium between the sympathetic and parasympathetic systems in the iris sphincter and dilator

27
Q

What are the three events that occur in the near triad?

A

Accommodation
Convergence
Miosis

28
Q

Which pathway/system is responsible for accommodation?

A

Parasympathetic

29
Q

The near triad is independent of what two things?

A

Illumination

Decreased accommodative ability (presbyopia)

30
Q

What occurs in light-near dissociation?

A

Can have accommodation, but absent pupil reaction

31
Q

What demographics have smaller pupils?

A

Old people
Diabetics
Chronic alcoholics
Those with pain or ocular inflammation

32
Q

When should the accommodative response be checked?

A

Only if the direct light response is abnormal/absent

33
Q

What is anisocoria?

A

Pupil size difference of more then 0.5 mm, may have lid involvement

34
Q

What is an amaurotic pupil?

A

Blind pupil

No direct light reflex

35
Q

What is Hutchinson’s pupil?

A

Fixed, dilated pupil

Unilateral

36
Q

If anisocoria is more noticeable in the dark, what isn’t working well?

A

Iris dilator muscle

37
Q

What things may cause anisocoria?

A
Miotic drops
Iritis
Horner's syndrome
Argyll Robertson pupil
Long standing Adie's pupil
38
Q

The sympathetic pathway to the eye is a ___ neuron arc

A

3

39
Q

Anhydrosis will occur in Horner’s syndrome only when the lesion occurs before ___.

A

Carotid bifurcation and superior cervical ganglion

40
Q

With what is herterchormia associated?

A

Congenital Horner’s syndrome

41
Q

Why does congenital Horner’s syndrome occur?

A

Brachial plexus injury during birth

42
Q

In children under 5, why might acquired Horner’s syndrome occur?

A

Neuroblastoma in the sympathetic chain of the chest and neck

43
Q

How do we rule out neuroblastoma in children?

A

Refer to pediatrician

44
Q

What are the symptoms of Adie’s Tonic Pupil?

A
80% unilateral
Dilated pupil
Poor reaction to light
Slow tonic re-dilation
De-nervated ciliary ganglion
Sectoral palsy of the iris sphincter
45
Q

Which pupil disorder becomes bilateral at a rate of 4% per year?

A

Adie’s Tonic pupil

46
Q

What happens to a longstanding Adie’s pupil?

A

It will become constricted

47
Q

What is light-near dissociation?

A

When the response to accommodation is stronger than the light response

48
Q

In light-near dissociation, what is the ratio of accommodation fibers to pupil fibers?

A

30:1

49
Q

What causes light-near dissociation?

A

Midbrain lesions that are close to the pretectal synapse

50
Q

When is light-near dissociation diagnostically valuable?

A

If the direct light reflex is absent or abnormal

51
Q

In which syndromes/diseases is the light-near dissociation phenomenon seen?

A
Adie's tonic pupil
Argyll-Robertson pupil
Diabetes
Dorsal midbrain syndrome
Aberrant regeneration of CN III: miosis with Adduction
Amyloidosis
52
Q

What is seen in Argyll-Robertson pupils?

A

Both pupils are constricted and irregular
Light-near dissociation
Dilate poorly in the dark
Respond poorly to dilating agents

53
Q

In which diseases is Argyll-Robertson pupil commonly seen?

A
Syphilis
Diabetes
Chronic alcoholism
Multiple sclerosis
Sarcoidosis
54
Q

APD is an asymmetry in which pathway?

A

Afferent pathway

55
Q

What is usually the cause of APD?

A

Massive retinopathy or optic neuropathy

56
Q

What does APD stand for?

A

Afferent Pupillary Defect

57
Q

How is APD detected?

A

By the swinging flashlight test

58
Q

Is APD present in functional amblyopia?

A

Nope

59
Q

APD is also known as what?

A

Marcus-Gunn pupil

60
Q

Can eyes with 20/20 acuity and normal visual fields have APD?

A

Yes

61
Q

What does PERRLA(-) stand for?

A

Pupils are Equal, Round, Reactive to light, Accommodation, no APD