Chapter 15 - Eyes Flashcards

1
Q

Which eyelid (upper/lower) is more mobile?

A

upper

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2
Q

What do eyelashes filter?

A

dust and dirt

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3
Q

What is the palpebral fissure?

A

open space between the eyelids

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4
Q

What is the limbus?

A

the border between the cornea and sclera

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5
Q

What is the canthus?

A

corner of the eye, angle where eyelids meet

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6
Q

What is the caruncle?

A

small fleshy mass containing sebaceous glands

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7
Q

What are the tarsal plates?

A

strips of connective tissue that give the upper eyelid shape

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8
Q

Where are the meibomian glands?

A

in the tarsal plates

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9
Q

What are meibomian glands?

A

modified sebaceous glands that lubricate eyelids

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10
Q

What do the meibomian glands do?

A

stop tears from overflowing, create airtight seal when eyes are closed

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11
Q

What is the conjunctiva?

A

transparent protective covering of the eye, thin mucous membrane

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12
Q

Where is the palpebral conjunctiva?

A

lines the eyelids, is clear

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13
Q

The palpebral conjunctiva had many ________ _______

A

blood vessels

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14
Q

Where is the bulbar conjuctiva?

A

overlies eyeball, sclera shows through

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15
Q

What is the role of the cornea?

A

protect iris and pupil

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16
Q

What does the lacrimal apparatus do?

A

provide constant irrigation to maintain moisture and lubrication

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17
Q

Where do tears drain?

A

the puncta

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18
Q

Where do the tears go after the puncta?

A

nasolacrimal sac, nasolacrimal duct, empty into inferior meatus in nose

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19
Q

What prevents air being forced into the nasolacrimal duct when the nose is blown?

A

tiny fold of mucous membrane

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20
Q

How many muscles attach the eye to its orbit?

A

6

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21
Q

What do extra ocular muscles allow?

A

straight and rotary movements

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22
Q

Name the 4 straight (rectus) muscles of the eye?

A
  1. superior
  2. inferior
  3. lateral
  4. medial
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23
Q

Name 2 slanting (oblique) muscles of the eye?

A
  1. superior
  2. inferior
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24
Q

What is conjugate movement of the eye?

A

each muscle is coordinated with the one in the other eye and ensures the axes remain parallel

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25
Q

Why are parallel axes important?

A

the human brain can tolerate seeing only one image

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26
Q

What kind of vision do humans have?

A

binocular, single-image

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27
Q

How many cranial nerves stimulate movement of the extra ocular muscles?

A

3

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28
Q

Which cranial nerve innervates the lateral rectus muscle?

A

CN VI abducens nerve

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29
Q

What does the lateral rectus muscle do?

A

abducts the eye (laterally towards temple)

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30
Q

Which cranial nerve innervates the superior oblique muscle?

A

CN IV (trochlear nerve)

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31
Q

What does the superior oblique muscle do?

A

moves the eye downward and inward toward the nose

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32
Q

Which cranial nerve innervates the superior, inferior, and medial rectus and all inferior oblique muscles?

A

CN III (oculomotor nerve)

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33
Q

What does the superior oblique muscle do?

A

look downward and inward

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34
Q

What are the 3 layers of the eye from superficial to deep?

A

sclera, choroid, retina

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35
Q

Which eye layer is vascular?

A

choroid

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36
Q

How can you examine the retina?

A

opthalmoscope

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37
Q

What is the sclera?

A

a tough, protective, white covering

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38
Q

What does the cornea do?

A

protect and refract light

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39
Q

What is the corneal reflex?

A

touch to the cornea stimulates a blink in both eyes

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40
Q

Which cranial nerves are involved in the corneal reflex?

A

CN V (trigeminal) carries sensation to the brain and CN VII (facial nerve) stimulates the blink

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41
Q

Why is the choroid darkly pigmented?

A

to prevent light from reflecting internally

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42
Q

What do the muscles of the ciliary body control?

A

thickness of the lens

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43
Q

What does the iris do?

A

controls the opening where light gets in

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44
Q

The iris ______ in bright light and to acomodate for near vision

A

contracts

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45
Q

Darker irises = darker _________

A

retina

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46
Q

Which part of the nervous system controls pupil size?

A

autonomic nervous system

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47
Q

Parasympathetic stimulation via CN ____ = pupil __________

A

III; constriction

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48
Q

Sympathetic stimulation = pupil __________

A

dilation

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49
Q

The lens _____ for focusing on near objects and ________ for far objects

A

bulges; flattens

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50
Q

Where is the anterior chamber?

A

posterior to the cornea, but anterior to iris and lens

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51
Q

Where is the posterior chamber?

A

behind iris, to the sides of the lens

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52
Q

Where is the aqueous humour in the chambers produced?

A

ciliary body

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53
Q

What does aqueous humour do?

A

deliver fluid and nutrients to surrounding tissues

54
Q

What determines intraocular pressure?

A

balance between amount of aqueous humour and outflow at the angle of the chamber

55
Q

Where are light waves changed into nerve impulses?

A

retina

56
Q

What is the optic disc?

A

area where fibres from retina converge to form the optic nerve

57
Q

Where is the optic disc located?

A

towards nasal side of retina

58
Q

Optic Disc characteristics:

A

-yellow-orange to pink colour
-round or oval shape
-distinct margins
-physiological cup

59
Q

Where is the macula located?

A

on the temporal side of the fundus

60
Q

What is the macula?

A

darker pigmented region surrounding the fovea

61
Q

What is the fovea centralis?

A

area of sharpest and keenest vision

62
Q

What does the macula do?

A

receive and transduce light into neural signals

63
Q

The image formed on the retina is ______ _____ and _______

A

upside down, and reversed

64
Q

What happens at the optic chiasm?

A

nasal fibres cross over, left optic tract has fibres from left half of each retina, and right optic tract contains fibres from the right half

65
Q

The right side of the brain looks at the _____ side of the world

A

left

66
Q

What is the pupillary light reflex?

A

normal constriction of the pupils when bright light shines on the retina

67
Q

The pupillary light reflex is a subcortical reflex arc meaning…

A

a person has no conscious control over it

68
Q

Bright light = direct light reflex…

A

constriction of THAT pupil

69
Q

Consensual light reflex

A

simultaneous constriction of the OTHER pupil

70
Q

What is fixation?

A

a reflex direction of the eye toward an object attracting a person’s attention

71
Q

What is accomodation?

A

adaptation of the eye for near vision

72
Q

How does accommodation work?

A

increasing curvature of the lens via ciliary muscles

73
Q

When does the macula begin developing?

A

age 4 months

74
Q

When does the macula mature?

A

age 8 months

75
Q

When does the infant establish binocularity and can fixate on a single image?

A

3 to 4 months

76
Q

Most neonates are born __________ but this gradually decreases

A

farsighted

77
Q

When does the eyeball reach adult size?

A

8 years of age

78
Q

Presbyopia

A

lens becomes hard and this decreases its ability to change shape and accommodate near vision

79
Q

The average onset of presbyopia is _____

A

40yo

80
Q

By age 70 the lens thickens and yellows, this is called…

A

nuclear sclerosis (beginning of a senile cataract)

81
Q

Macular degeneration

A

breakdown of cells in the macula that causes loss of central vision

82
Q

What is the most common cause of blindness?

A

age-related macular degeneration

83
Q

What increases risk for menopause?

A

-women, especially early menopause

84
Q

With AMD is peripheral vision affected?

A

no, only sharp, straight vision

85
Q

What is cataract formation?

A

lens opacity

86
Q

What causes cataracts?

A

clumping of proteins in the lens

87
Q

What age is cataract formation expected?

A

70 years old

88
Q

What are risk factors for cataracts?

A

-age
-diabetes mellitus
-steroids
-ocular trauma
-previous surgery

89
Q

What is glaucoma?

A

increased intra ocular pressure

90
Q

What is chronic open-angle glaucoma?

A

most common form of the disease, involving damage to the optic nerve

91
Q

__________ retinopathy is the leading cause of visual impairment in people under 65

A

diabetic

92
Q

Visual acuity worse than 20/___ disqualifies people from obtaining a drivers license in Canada

A

50

93
Q

What is it called when vision can’t be corrected better than 20/200 or better than 20 degrees?

A

legal blindness

94
Q

Risk factors for glaucoma:

A

->60 yoa
-being of African descent
-being a woman
-increased intra ocular pressure (>21mmHg)
-family history
-steroid use
-hypertension
-eye injury
-severe myopia
-diabetes

95
Q

Aqueous humour originates in which chamber and moves to…

A

starts in posterior chamber moves to anterior chamber

96
Q

How does IOP increase?

A

if fluid flow is blocked

97
Q

Which type of glaucoma is most common?

A

open-angle glaucoma

98
Q

What is open-angle glaucoma?

A

angle between iris and cornea is open but fluid is slow to drain

99
Q

What is closed angle glaucoma?

A

when space between cornea and iris is narrower than normal

100
Q

Are there any symptoms that warn of open-angle glaucoma?

A

no

101
Q

What are the symptoms of closed angle glaucoma?

A

blurred vision, sensitivity to light, nausea, halos around the eyes

102
Q

None of the Canadian provinces cover the cost of eye exams for people age ___-___

A

20-64

103
Q

Floaters occur with…

A

myopia or after middle age as a result of condensed vitreous fibres

104
Q

Halos around lights occur with…

A

acute narrow-angle glaucoma

105
Q

What is scotoma?

A

a blind spot in the visual field surrounded by an area of normal or decreased vision

106
Q

Scotoma occurs with…

A

glaucoma and disorders of the optic nerve

107
Q

Night blindness occurs with…

A

optic atrophy, glaucoma, or Vit A deficiency

108
Q

Photophobia

A

inability to tolerate light

109
Q

Strabismus

A

a deviation in the anteroposterior axis of the eye

110
Q

Diplopia

A

double vision

111
Q

Epiphora

A

excessive tearing

112
Q

Which 2 diseases are a risk to newborn vision?

A

herpes and gonorrhoea

113
Q

If a patient misses 1 or 2 letters on the smallest line they can read does it count?

A

yes, their vision is still equal to that line

114
Q

What does 20/20 vision mean?

A

you can read at 20 feet what the normal eye can at 20 feet

115
Q

What does the confrontation test measure?

A

peripheral vision

116
Q

What are normal results of the confrontation test?

A

-50 degrees upward
-90 degrees temporal
-70 degrees downward
-60 degrees nasal

117
Q

What does the corneal light reflex test?

A

parallel alignment of the eye axes

118
Q

What does the cover-uncover test detect?

A

small degrees of deviated alignment

119
Q

What does the diagnostic positions test reveal?

A

muscle weakness during movement

120
Q

Nystagmus

A

fine oscillating movement seen around the iris

121
Q

When is mild nystagmus normal?

A

extreme lateral gaze

122
Q

Lid Lag

A

white rim of sclera seen between the eyelid and iris during eye movement

123
Q

When is eversion of the upper eyelid used?

A

when inspecting conjunctiva in case of pain or suspicion of foreign body

124
Q

Aniscoria

A

having pupils of two different sizes

125
Q

What should you note about pupil size in the acute care setting?

A

record size in mm to compare changes

126
Q

PERRLA

A

pupils equal round react to light and accomodation

127
Q

What is the unit of strength of each lens is the ______

A

dioptre

128
Q

Red Reflex

A

red glow filling the pupil caused by the reflection of your ophthalmoscope light

129
Q

left off page 764

A
130
Q
A