Chapter 20 Flashcards
1
Q
what is the first spot of refraction?
A
cornea
2
Q
where is the second spot of refraction?
A
lens
3
Q
how does the lens change shape during accomadation?
A
ciliary muscle
- distance = flattens
- close = rounds
4
Q
pupil
A
light rays enter, size determined by iris
5
Q
retina
A
contains photoreceptors
6
Q
macula
A
post on the retina that provides the greatest visual acuity
7
Q
fovea
A
central portion of the macula
8
Q
signs and symptoms of eye disorders resulting in decreased visual acuity ..
A
- visual field defects (focal areas of blindness)
- pain (manifestation of trauma, infection, or increased intraocular pressure)
- blurred vision
9
Q
strabismus
A
crossed eyes
10
Q
etiology of strabimus
A
- eye muscles don’t work together
- confuses the brain
- brain ignores image from weaker eye
11
Q
amblyopia
A
lazy eye
12
Q
nystagmus
A
fast, uncontrollable eye movements, one or both eyes
13
Q
etiology of nystagmus
A
- congenital
- acquired from head injury, stroke, inner ear disorders, drugs/medication
14
Q
tests for eye disorders
A
- visual acuity tests
- ophthalmoscope (retina)
- tonometer (measures intraocular pressure)
- slit-lamp (cornea, iris, and lens)
15
Q
hyperopia (farsighted)
A
can see far, struggle close up, shorter eyeball
16
Q
myopia (nearsighted)
A
trouble seeing far, can see close up, longer eyeball
17
Q
presbyopia
A
accommodation changes due to age
18
Q
astigmatism
A
curvature in cornea
19
Q
diagnosing refraction disorders
A
snellen eye chart
20
Q
general signs and symptoms of refraction disorders
A
- poor vision
- headaches
- eyestrain
- fatigue
- burning
21
Q
myopia signs and symptoms
A
- blurred vision
- squinting when looking at distant objects
22
Q
signs and symptoms of hyperopia
A
difficulty focusing on near objects
23
Q
procedures for refractive disorders
A
- laser-assisted in situ keratomileusis (LASIK)
- phakic intraocular lens implant (nearsightedness)
24
Q
what kind of corrective lens does myopia need?
A
concave lens
25
what kind of corrective lens does hyperopia need?
convex lens
26
what kind of corrective lens does astigmatism need?
glasses or hard contact lens
27
what kind of corrective lens does presbyopia need?
reading glasses, or bifocal lens
28
conjuctivitis
bacterial, fungal, viral, or allergy infection in the conjuctiva causing redness and inflammation
29
corneal keratitis
infection, typically unilateral, can lead to vision loss from scarring
30
corneal kertopathy (band keratopathy)
deposition of calcium salts within cornea, leads to pain and decreased acuity
31
corneal dystrophy
bilateral, genetic, abnormal accumulation in cornea (clouding)
32
cataracts
opacity of lens (no longer clear), age related degeneration
33
what is the leading cause of blindness in adults worldwide?
cataracts
34
what percentage of adults will have cataracts by age 65?
90%
35
symptoms of cataracts
pupil looks milky white
36
treatment of cataracts
surgery (LASIK)
37
glaucoma
optic nerve is damaged by abnormally increased intraocular pressure (irreversible)
38
what is the second most common cause of blindness in the world?
glaucoma
39
what causes glaucoma?
build up of aqueous humor (intraoccular pressure)
40
acute glaucoma
possible loss of vision within 1 day, emergency
41
signs and symptoms of glaucoma
- severe eye pain
- blurred vision
- eye redness
- light halos
- nausea
- vomiting
42
risk factors of glaucoma
- age
- refractive disorders
- genetics
- hypertension
- diabetes
43
retinal detachment
retinal peels away from underlying support tissue, emergency, can lead to blindness
44
symptoms of retinal detachment
spots, floaters, flashes of light, not painful
45
etiology of retinal detachment
- trauma to eye
- genetic disease (marfan syndrome)
- extreme nearsightedness
46
treatment of retinal detachment
surgery
47
macular degeneration
damage to macular, does not lead to complete loss of vision
48
what is the leading cause of vision loss in people over 60?
macular degeneration
49
risk factors of macular degeneration
- age
- obesity
- UV light exposure
- smoking
- family history
- ethnicity
50
treatment for macular degeneration
no cure
51
hypertensive retinopathy
damage to retina due to hypertension
52
etiology of hypertensive retinopathy
- vessel narrowing
- microinfarcts
- hemorrhages
- exudates/edema
53
hypertensive retinopathy leads to..
- dim vision
- vision loss
- double vision
54
treatment of hypertensive retinopathy?
meds to decrease BP
55
diabetic retnopathy
retina sensitive to hyperglycemia, damage to blood vessels in cornea
56
how much more likely are diabetics to go blind than normal individuals?
20x
57
what can diabetic retinopathy lead to?
- microhemorrhages
- edema
- neovascularization (new blood vessel growth)
58
symptoms of diabetic retinopathy
- spots/floaters in eyes
- blurred vision
- empty spot in vision
59
treatment of diabetic retinopathy
- blood glucose control
- surgery (seal leaking vessels)
60
eye diseases in diabetic
- glaucoma
- retinal detachment
- cataracts
- diabetic retinopathy
61
is color deficient sex linked?
x-linked recessive
62
types of color deficient blindness
- red-green
- blue-yellow (trouble differentiating shades of blue and green)
- complete absence of color vision (rare)
63
retinoblastoma
- children
- rare malignant tumor of retinal cells
- autosomal dominant inheritance (Rb1 gene)
64
malignant melanoma
- adults
- ocular melanoma (from melanocytes in choroid layer, effects iris)
- worse prognosis than skin melanoma
65
organ failure (blindness)
- defined as visual acuity 20/200
- 4/1000 people legally blind
66
causes of blindness
- lesions
- developmental
- trauma
