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Ocular Physiology > Eyelids > Flashcards

Eyelids Flashcards

(85 cards)

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1
Q

why is the skin in the eyelids fat free

A

so they are lighter for the muscles to lift for how often we blink

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2
Q

what is blepharochalsis

A

inflammation of the eyelid

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3
Q

what type of carcinoma is related to UVR exposure

A

basal cell carcinoma

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4
Q

which lids (upper or lower) are affected by benign growths

A

both have an equal change of getting them

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5
Q

which lid (upper or lower) has a greater chance of developing a malignant tumor

A

the lower lid is four times more likely to get one

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6
Q

why wouldn’t the upper lid be as common in getting malignant tumors

A

the eyebrows protect the upper lid from the sun

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7
Q

what does the levator palpebrae superioris do

A

elevates the upper lid (striated muscle)

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8
Q

what do the Muller muscle fibers do

A

modulate position of lids of the open eye

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9
Q

what marks the palpebral portion from the orbital portion of the lid

A

the insertion of the levator palpebrae superioris (superior palpebral sulcus)

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10
Q

when would someone have an absence of the superior palpebral sulcus

A

certain ethnicities will not have a distinct line or if there is ptosis (especially congenital)

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11
Q

what does the orbicularis oculi do

A

(striated voluntary muscle) closes the lids and helps hold the lid tightly against the eye, assists in spreading tears and flushing waste

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12
Q

what innervates the orbicularis oculi

A

CN 7- facial

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13
Q

what would happen if CN 7-facial of the orbicularis oculi was paralyzed

A

dry eye conditions, lagophthalmus (inability to close lids)

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14
Q

at what point does the levator palpebrae superioris become tendinous

A

as it enters the lid becoming the “aponeurosis of the levator”

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15
Q

what innervates the levator palpebrae superioris

A

CN 3 oculomotor nerve

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16
Q

what type of innervation does the tarsal muscle (Mullers muscle) superior and inferior have

A

sympathetic innervation

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17
Q

what does contraction of the tarsal muscle (mullers) do

A

aids the action of the levator

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18
Q

what would damage to the tarsal muscle do

A

damage to the sympathetic innervation causes a droopy lid (ptosis)

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19
Q

what type of tissue is in the submuscular areolar tissue

A

loose connective tissue between the muscle and tarsal plate (fat free)

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20
Q

what is in the fibrous layer of the eyelid

A

dense fibrous tissue and collagen that gives firmness and shape to lids (tarsal plate); more developed collagen in the upper lid

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21
Q

what is floppy eyelid syndrome

A

the upper lids are flaccid and easily everted

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22
Q

what causes floppy eyelid syndrome

A

decreased tarsal elastin and genetic abnormalities of collagen and elastin

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23
Q

what are the symptoms of floppy eyelid syndrome

A

burning and irritation, contact between eye and pillow during sleep, inadequate distribution of tear film, and meibomian gland dysfunction

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24
Q

what is floppy iris syndrome

A

complication during cataract surgery, floppy iris will come out of incision

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25
how many cilia (eyelashes) are in the upper lid
100-150
26
how many cilia (eyelashes) are in the lower lid
50-75
27
what is the life-span of the cilia (eyelashes)
3-5 months
28
if an eyelash is forcibly removed, how long until it grows back
about 2 months
29
what is the chief secretion of the eyelid
sebum, oily material from the meibomian glands
30
how many meibomian glands are in each tarsal plate
about 30 in each tarsus
31
what causes the meibomian glands to secrete the sebum
pressure on the glands
32
what is the arterial supply to the eyelids
facial system (external carotid artery) and orbital system (internal carotid artery)
33
what is the venous drainage of the eyelids
superficial (pre-tarsal) system and deep (post tarsal) system
34
what are the lymphatic systems in the eyelid
superficial or pre-tarsal plexus and deep or post-tarsal plexus
35
what would be affected on the face with paralysis of CN 7
causes a brow to be lower on the affected side, lowering of the corner of the mouth
36
weakness of which CN would cause ptosis of the upper lid
CN 3 oculomotor
37
paralysis of which CN would cause complete closure of the upper lid
CN 3 oculomotor
38
complete paralysis of which muscle would cause complete closure of the upper lid
the levator
39
why wouldn't you have diplopia with a third nerve palsy
the eyelid would be completely closed (if you lifted the lid the patient would have diplopia)
40
what muscle would try to compensate in weakness of the levator superioris
the frontalis muscle would contract in an attempt the raise the upper lid
41
what would sympathetic paralysis of Mullers muscle cause
a minor degree of ptosis (component of Horner's syndrome)
42
what drug causes reversal of the ptosis of sympathetic paralysis
weak solutions of epinephrine (topical)
43
what are the 3 symptoms of Horner's syndrome
ptosis, miosis and anhydrosis (usually half the face)
44
what are the 3 muscles of the eyebrow
the frontalis, orbicularis oculi, and corrugator supercilii
45
what does the frontalis muscle do
raises the brow in expression of surprise
46
where is the frontalis muscle located
oriented radially over the forehead
47
what does the corrugator supercilii do
pulls eyebrows together (frown)
48
what is Bell's phenomenon
the globe turns upward as the eyelids are forced closed, not found during normal blinking
49
what are the 3 primary sensory causes of reflex blinking
tactile, optic (strong lights) and auditory sensations
50
what is a dazzle reflex
the involuntary avoidance response to a light shined into the eye
51
what is a menace reflex
blink reflex caused by a sudden motion towards the eye
52
what are two examples of common optically initiated blink reflexes
dazzle and menace reflexes
53
what is an aesthesiometer
an instrument used to measure the corneal reflex
54
what is a reflex blink
high-speed response to tactile and proprioceptive (detects motion) stimuli
55
what is blepharospasm
slow, sustained closure to nocieptive (pain) stimuli
56
what is spontaneous blinking
occurs on a regular basis without external stimuli
57
what may cause the rate a person has spontaneous blinking
levels of visual activity, emotional states and environmental conditions (dryness or windiness)
58
do infants have spontaneous blinking
it is extremely low or absent in infants
59
which eyelid moves during spontaneous blinking
the upper lid does the most movement, lower lid remains stationary
60
what type of motion does the palpebral fissure make during a blink
a zipper-like motion lateral to medial
61
what is the spontaneous blink rate
15 x per minute
62
what is the duration of a blink
300-400 msec
63
what is the average time between blinks
2.8 sec
64
what causes a blepharospasm
an idiopathic disorder of neuromuscular control (orbicularis oculi)
65
what treatment can be offered for blepharospasms
temporary relief with botulinum-A toxin (Botox) every 3 months
66
what is myokymia
fibrillary twitching of the eyelids
67
what is dystonias
involuntary muscle contraction and slow repetitive movement
68
what causes myokymia
fatigue, thyrotoxicosis, or stress (most common)
69
what is lagophthalmos
incomplete closure of eyes during sleep
70
what can lagophthalmos cause
desiccation and excessive exposure of the lower portions of the cornea
71
what causes an ectropion
weakness of the orbicularis oculi, age-related or weakness of CN 7 of Bells Palsy
72
what are the symptoms of ectropion
epiphora (excessive tearing) and poor blink closure
73
what is senile or age-related ectropion
secondary to loss of tone and loss of orbital fat deep to the eye
74
what are characteristics of late stage trachoma (chlamydia infection) and ocular pemphigus
cicatrical entropion and trichiasis
75
what are the dimensions of a normal palpebral fissure
8-11mm wide (vertically) and 27-30mm long (horizontally)
76
what would cause a widening of the palpebral fissure
any process that results in proptosis or forward movement of the globe within the orbit
77
what would cause a narrowing of the palpebral fissure
abnormal recession of the globe into the orbit
78
which measurement, exophthalmos or lid retraction, would provide more important information in thyroid eye disease
the degree of lid retraction (measure the vertical palpebral fissure)
79
what is Collier's Sign
retraction of the upper eyelid in thyrotoxicosis
80
what is Von Grafe's Sign
delay of movement of the upper lid when shifting gaze from up to down; causes a staring expression
81
what is the length of time that is required for our brain to detect that the visual input was obscured
30 msec
82
If the duration of a blink is 300-400 msec and it takes 30 msec to detect obscured visual input, why don't we realize when we are blinking
the brain learns to suppress the feeling over time
83
who might experience lagophthalmos
common in a few individuals and a consequence of some diseases
84
why is measuring the exophthalmos in a thyroid eye disease not as helpful as measuring the vertical palpebral fissure
exophthalmometry measurements are remarkably similar to normal patients (early in the disease)
85
what are two symptoms of thyrotoxicosis
collier's sign and Von Grafe's sign

Ocular Physiology (6 decks)

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