Chapter 15 - Eyes Flashcards
1
Q
Which eyelid (upper/lower) is more mobile?
A
upper
2
Q
What do eyelashes filter?
A
dust and dirt
3
Q
What is the palpebral fissure?
A
open space between the eyelids
4
Q
What is the limbus?
A
the border between the cornea and sclera
5
Q
What is the canthus?
A
corner of the eye, angle where eyelids meet
6
Q
What is the caruncle?
A
small fleshy mass containing sebaceous glands
7
Q
What are the tarsal plates?
A
strips of connective tissue that give the upper eyelid shape
8
Q
Where are the meibomian glands?
A
in the tarsal plates
9
Q
What are meibomian glands?
A
modified sebaceous glands that lubricate eyelids
10
Q
What do the meibomian glands do?
A
stop tears from overflowing, create airtight seal when eyes are closed
11
Q
What is the conjunctiva?
A
transparent protective covering of the eye, thin mucous membrane
12
Q
Where is the palpebral conjunctiva?
A
lines the eyelids, is clear
13
Q
The palpebral conjunctiva had many ________ _______
A
blood vessels
14
Q
Where is the bulbar conjuctiva?
A
overlies eyeball, sclera shows through
15
Q
What is the role of the cornea?
A
protect iris and pupil
16
Q
What does the lacrimal apparatus do?
A
provide constant irrigation to maintain moisture and lubrication
17
Q
Where do tears drain?
A
the puncta
18
Q
Where do the tears go after the puncta?
A
nasolacrimal sac, nasolacrimal duct, empty into inferior meatus in nose
19
Q
What prevents air being forced into the nasolacrimal duct when the nose is blown?
A
tiny fold of mucous membrane
20
Q
How many muscles attach the eye to its orbit?
A
6
21
Q
What do extra ocular muscles allow?
A
straight and rotary movements
22
Q
Name the 4 straight (rectus) muscles of the eye?
A
- superior
- inferior
- lateral
- medial
23
Q
Name 2 slanting (oblique) muscles of the eye?
A
- superior
- inferior
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
25
Why are parallel axes important?
the human brain can tolerate seeing only one image
26
What kind of vision do humans have?
binocular, single-image
27
How many cranial nerves stimulate movement of the extra ocular muscles?
3
28
Which cranial nerve innervates the lateral rectus muscle?
CN VI abducens nerve
29
What does the lateral rectus muscle do?
abducts the eye (laterally towards temple)
30
Which cranial nerve innervates the superior oblique muscle?
CN IV (trochlear nerve)
31
What does the superior oblique muscle do?
moves the eye downward and inward toward the nose
32
Which cranial nerve innervates the superior, inferior, and medial rectus and all inferior oblique muscles?
CN III (oculomotor nerve)
33
What does the superior oblique muscle do?
look downward and inward
34
What are the 3 layers of the eye from superficial to deep?
sclera, choroid, retina
35
Which eye layer is vascular?
choroid
36
How can you examine the retina?
opthalmoscope
37
What is the sclera?
a tough, protective, white covering
38
What does the cornea do?
protect and refract light
39
What is the corneal reflex?
touch to the cornea stimulates a blink in both eyes
40
Which cranial nerves are involved in the corneal reflex?
CN V (trigeminal) carries sensation to the brain and CN VII (facial nerve) stimulates the blink
41
Why is the choroid darkly pigmented?
to prevent light from reflecting internally
42
What do the muscles of the ciliary body control?
thickness of the lens
43
What does the iris do?
controls the opening where light gets in
44
The iris ______ in bright light and to acomodate for near vision
contracts
45
Darker irises = darker _________
retina
46
Which part of the nervous system controls pupil size?
autonomic nervous system
47
Parasympathetic stimulation via CN ____ = pupil __________
III; constriction
48
Sympathetic stimulation = pupil __________
dilation
49
The lens _____ for focusing on near objects and ________ for far objects
bulges; flattens
50
Where is the anterior chamber?
posterior to the cornea, but anterior to iris and lens
51
Where is the posterior chamber?
behind iris, to the sides of the lens
52
Where is the aqueous humour in the chambers produced?
ciliary body
53
What does aqueous humour do?
deliver fluid and nutrients to surrounding tissues
54
What determines intraocular pressure?
balance between amount of aqueous humour and outflow at the angle of the chamber
55
Where are light waves changed into nerve impulses?
retina
56
What is the optic disc?
area where fibres from retina converge to form the optic nerve
57
Where is the optic disc located?
towards nasal side of retina
58
Optic Disc characteristics:
-yellow-orange to pink colour
-round or oval shape
-distinct margins
-physiological cup
59
Where is the macula located?
on the temporal side of the fundus
60
What is the macula?
darker pigmented region surrounding the fovea
61
What is the fovea centralis?
area of sharpest and keenest vision
62
What does the macula do?
receive and transduce light into neural signals
63
The image formed on the retina is ______ _____ and _______
upside down, and reversed
64
What happens at the optic chiasm?
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
The right side of the brain looks at the _____ side of the world
left
66
What is the pupillary light reflex?
normal constriction of the pupils when bright light shines on the retina
67
The pupillary light reflex is a subcortical reflex arc meaning...
a person has no conscious control over it
68
Bright light = direct light reflex...
constriction of THAT pupil
69
Consensual light reflex
simultaneous constriction of the OTHER pupil
70
What is fixation?
a reflex direction of the eye toward an object attracting a person's attention
71
What is accomodation?
adaptation of the eye for near vision
72
How does accommodation work?
increasing curvature of the lens via ciliary muscles
73
When does the macula begin developing?
age 4 months
74
When does the macula mature?
age 8 months
75
When does the infant establish binocularity and can fixate on a single image?
3 to 4 months
76
Most neonates are born __________ but this gradually decreases
farsighted
77
When does the eyeball reach adult size?
8 years of age
78
Presbyopia
lens becomes hard and this decreases its ability to change shape and accommodate near vision
79
The average onset of presbyopia is _____
40yo
80
By age 70 the lens thickens and yellows, this is called...
nuclear sclerosis (beginning of a senile cataract)
81
Macular degeneration
breakdown of cells in the macula that causes loss of central vision
82
What is the most common cause of blindness?
age-related macular degeneration
83
What increases risk for menopause?
-women, especially early menopause
84
With AMD is peripheral vision affected?
no, only sharp, straight vision
85
What is cataract formation?
lens opacity
86
What causes cataracts?
clumping of proteins in the lens
87
What age is cataract formation expected?
70 years old
88
What are risk factors for cataracts?
-age
-diabetes mellitus
-steroids
-ocular trauma
-previous surgery
89
What is glaucoma?
increased intra ocular pressure
90
What is chronic open-angle glaucoma?
most common form of the disease, involving damage to the optic nerve
91
__________ retinopathy is the leading cause of visual impairment in people under 65
diabetic
92
Visual acuity worse than 20/___ disqualifies people from obtaining a drivers license in Canada
50
93
What is it called when vision can't be corrected better than 20/200 or better than 20 degrees?
legal blindness
94
Risk factors for glaucoma:
->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
Aqueous humour originates in which chamber and moves to...
starts in posterior chamber moves to anterior chamber
96
How does IOP increase?
if fluid flow is blocked
97
Which type of glaucoma is most common?
open-angle glaucoma
98
What is open-angle glaucoma?
angle between iris and cornea is open but fluid is slow to drain
99
What is closed angle glaucoma?
when space between cornea and iris is narrower than normal
100
Are there any symptoms that warn of open-angle glaucoma?
no
101
What are the symptoms of closed angle glaucoma?
blurred vision, sensitivity to light, nausea, halos around the eyes
102
None of the Canadian provinces cover the cost of eye exams for people age ___-___
20-64
103
Floaters occur with...
myopia or after middle age as a result of condensed vitreous fibres
104
Halos around lights occur with...
acute narrow-angle glaucoma
105
What is scotoma?
a blind spot in the visual field surrounded by an area of normal or decreased vision
106
Scotoma occurs with...
glaucoma and disorders of the optic nerve
107
Night blindness occurs with...
optic atrophy, glaucoma, or Vit A deficiency
108
Photophobia
inability to tolerate light
109
Strabismus
a deviation in the anteroposterior axis of the eye
110
Diplopia
double vision
111
Epiphora
excessive tearing
112
Which 2 diseases are a risk to newborn vision?
herpes and gonorrhoea
113
If a patient misses 1 or 2 letters on the smallest line they can read does it count?
yes, their vision is still equal to that line
114
What does 20/20 vision mean?
you can read at 20 feet what the normal eye can at 20 feet
115
What does the confrontation test measure?
peripheral vision
116
What are normal results of the confrontation test?
-50 degrees upward
-90 degrees temporal
-70 degrees downward
-60 degrees nasal
117
What does the corneal light reflex test?
parallel alignment of the eye axes
118
What does the cover-uncover test detect?
small degrees of deviated alignment
119
What does the diagnostic positions test reveal?
muscle weakness during movement
120
Nystagmus
fine oscillating movement seen around the iris
121
When is mild nystagmus normal?
extreme lateral gaze
122
Lid Lag
white rim of sclera seen between the eyelid and iris during eye movement
123
When is eversion of the upper eyelid used?
when inspecting conjunctiva in case of pain or suspicion of foreign body
124
Aniscoria
having pupils of two different sizes
125
What should you note about pupil size in the acute care setting?
record size in mm to compare changes
126
PERRLA
pupils equal round react to light and accomodation
127
What is the unit of strength of each lens is the ______
dioptre
128
Red Reflex
red glow filling the pupil caused by the reflection of your ophthalmoscope light
129
left off page 764
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