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PPO 1a > Lecture Two > Flashcards

Lecture Two Flashcards

1
Q

Define Ataxia

A

loss of full control of bodily movements

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2
Q

If you observe a head tilt in patient what disease could be triggering this?

A

Strabismus, eye turn, head tilt could be compensating for this.

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3
Q

Define Adnexa

A

all structures surrounding what it is talking about i.e. all structures surrounding eye.

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4
Q

Define palpebral aperture

A

space between upper and lower eyelid

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5
Q

If the lower lid was protruding what could be happening? if it was intruding?

A

protruding could mean the tears are not being held in.

intruding could mean scratching of the cornea.

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6
Q

Define edema, hyperemia and hemorrhage.

A

edema: excess of fluid causing swelling
hyperemia: excess of blood in vessels
hemorrhage: bleeding

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7
Q

If external observation is all normal what do you record?

A

“eyes quiet, no asymmetries” indicate you did observe patient. do NOT write within normal limits. otherwise describe any abnormalties/asymmetries.

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8
Q

Pupilary distance measures what distance? how many measures of this do we do?

A

distance between pupil center of each eye.

two one for distance one for near.

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9
Q

What are average distance PD values in adults? average near values?

A

distance: 54-68mm
near: 2-4mm smaller than distance. both are smaller for children.

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10
Q

Central vision has what characteristics and involves what receptors? Peripheral vision?

A

involves cones, more detailed and colored.

involves rods, more gross and motion detection.

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11
Q

Visual field test measures what?

A

measure of sensitivity of central and peripheral visual fields.

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12
Q

Examples of peripheral vision defects?

A

glaucoma, retinitis pigmentosa

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13
Q

Examples of central vision defects?

A

AMD

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14
Q

Define hemianopia

A

half of visual field is gone i.e. all left side

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15
Q

Finger counting Visual Field test only tests for gross defects in which visual field?

A

peripheral visual field

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16
Q

Which visual field test can test for central vision?

A

Facial fields

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17
Q

Define Scotoma

A

gap in vision

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18
Q

another form of visual field testing besides static?

A

Kinetic. involves two people, one in back of patient brings object into peripheral field and front observer looks when patients eyes move.

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19
Q

Bruckners test looks for what three things?

A
  1. Eye health
  2. Binocular Vision (strabismus)
  3. Refractive error
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20
Q

Amblyopia caused by 1 of 3 reasons what are the three reasons?

A
  1. refractive
  2. strabismic
  3. deprivation
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21
Q

Light hits a surface of an object and then does what?

A

absorbed or reflected. more absorption object appears darker.

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22
Q

Newton found what with color?

A

White light going into the prism gave all colors. therefore white light has all wavelengths.

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23
Q

Trichromatic theory of color vision thought what?

A

3 types of photoreceptors sensitive to red/yellow/blue. only three wavelengths needed to create all colors. the three different types thought to be S (more sensitive to short wavelengths), M (more sensitive to medium wavelengths) and L (more sensitive to larger wavelengths)

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24
Q

What is the difference between S, M and L cones? Do rods differ?

A

Different opsins.

No. they all have rhodopsin (peak around 498nm)

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25
Q

What is the peak for S cones? Opsin type?

A

peak 430 nm, cyanolabe

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26
Q

What is the peak for M cones? opsin type?

A

peak 535nm, chlorolabe

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27
Q

What is the peak for L cones? opsin type?

A

peak 565nm, Erytholabe

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28
Q

Which type of cones are there the most of?

A

very few S cones, more M/L cones.

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29
Q

What varies with wavelength?

A

the probability that a photon will be absorbed

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30
Q

Trichromatic theory does not explain what?

A

after images or color appearance

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31
Q

Opponent process theory of color vision describes what?

A

what happens beyond photoreceptors

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32
Q

Normal color vision is called? how many photopigments?

A

Trichromatic: 3 types of photopigments

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33
Q

What is Anomalous Trichromat?

A

3 types of photopigment but one has abnormal sensitivity function (most common)

34
Q

What is Dichromacy?

A

only two types of photopigments, third one is absent or defective

35
Q

What is Monochromacy?

A

total color blindness, two cone types missing. only one pigment.

36
Q

Anomalous Trichromat has one opsin not normal, what are the three different types?

A
  1. Protanomaly/protanomalous trichromat: L-opsin altered (response toward green): poor red/green discrimination.
  2. Deuteranomaly/deuteranomalous trichromat: M opsin altered (response toward red) mildy affects red/green hue discrimination (most common in males)
  3. Tritanomaly/Tritanomalous Trichromat: S opsin altered. very rare. affects blue/yellow discrimination.
37
Q

Dichromacy has 2 pigments, what are the three different types?

A
  1. Protanope: absence of L cones
  2. Deutenarope: absence of M cones
  3. Tritanope: absence of S cones, rare.
  4. tetartanopia: no yellow
38
Q

Monochromacy total color blindness only one type of photoreceptor, what are the two types?

A
  1. Rod monochromacy: no cones, abnormal vision, achromatopsia
  2. Cone monochromacy: color blindness, cant distinguish hues otherwise normal vision.
39
Q

Signs that color vision defects are congenital?

A
  1. both eyes are equally affected
  2. stable over time
  3. nearly always red green defects
  4. usually VA and VF not affected
  5. higher incidence in males
40
Q

Males much more commonly have color defects what is the percent?

A

8% in males (likely congenital), 0.4% in females (likely acquired)

41
Q

Signs that color vision defects are acquired?

A
  1. asymmetry
  2. pathological process
  3. changes overtime
  4. decreased VA
  5. often blue/yellow defect but can be red/green
  6. random mix of results in testing
  7. equal prevalence in male/female.
42
Q

Blue/yellow acquired color vision defects could be due to what diseases? Red green?

A

B/Y: outer retina/media changes (i.e. in lens, cataract)

R/G: inner retina diseases i.e. optic nerve, visual pathway or visual cortex, MS.

43
Q

Other diseases that can cause color vision defects?

A
  1. diabetes mellitus (DM)
  2. Alcoholism
  3. MS
  4. Medications
44
Q

three major groups of color vision tests are?

A
  1. Color Matching
  2. Pseudoisochromatic Plate tests (Ishihara, HRR, most common one)
  3. Color arrangement tests
45
Q

Disadvantage of Ishihara?

A

only tests for congenital red/green defects

46
Q

What VA must the patient have in order to do the Ishihara test?

A

20/400 or better.

47
Q

HRR advantages?

A

can detect both R/G and B/Y defects. For R/G can determine is its protan or deuteran and whether it is mild, moderate or severe.

48
Q

Scattered results in HRR could indicate?

A

malingering, acquired color vision defects or monochromatism.

49
Q

Are acquired color defects common or rare in children?

A

RARE. if they do have one its almost always R/G.

50
Q

Define persistant pupilary membrane

A

remaining embryonic tissue in the pupil

51
Q

Define epicapsular stars

A

persistent pigment on anterior surface of lens, usually benign

52
Q

Define Mittendorf dot

A

remaining embryonic tissue on posterior surface of lens

53
Q

Define Mydriasis, Miosis and Anisocoria

A

dilated pupil
constricted pupil
pupils are different sizes

54
Q

Four functions of the pupil

A
  1. control retinal illumination
  2. facilitate light/dark adaptation
  3. reduce optical aberrations
  4. increase depth of focus i.e. PH effect
55
Q

Average pupil diameter? is hippus normal? do pupils normally differ in size?

A

1.1-8.5 mm
pupilary unrest: very normal however may be abnormal in disease or cease of hippus may be abnormal.
In most individuals the pupils are the same size and shape.

56
Q

Pupil size depends on?

A

age (older patients 60-70 have generally smaller pupils), light intensity, emotional state

57
Q

Define amplitude of pupils? As we have increasing stimulus intensity, latency (onset) does what? rate (speed) does what?

A

extent of pupils response to light

Latency decreases, rate increases

58
Q

Parasympathetic causes what to pupils? sympathetic?

A

Constriction (causes circular muscles to contract around pupil), also involved in accommodation.
Dilation (causes radial muscles to contract)

59
Q

Afferent pathways go from what to what?

Efferent?

A

Afferent: eyes to CNS
Efferent: CNS to eyes

60
Q

Sphincter muscle is what? What does it cause when it constricts? innervated by what?
Dilator?

A

annular band of smooth muscle around pupil, constriction causes miosis. parasymp.
Myoepithelial cells running radially, constrction causes mydriasis. symp.

61
Q

One of the main reasons pupil testing is so important?

A

neuro-opthalmologic test! evaluation of visual pathways and ANS (para/symp).

62
Q

At the optic chiasm, do all the fibres cross paths to the opposite side?

A

NO not 50/50. some go to the same side. 54% cross paths (nasal fibres) and 47% stay on the same side (temporal fibres).

63
Q

Damage of optic tract may cause what?

A

afferent pupillary defect (RAPD)

64
Q

When ganglion axons are entering optic nerve is this a 50/50 split?

A

YES.

65
Q

If a patient has ptosis what would you look for?

A

pupils, EOM and accommodation because they are all grouped with CN3.

66
Q

Synkinetic Triad (or Near response) when changing view from distant to near your eyes do what three things?

A
  1. Converge
  2. Accommodate (ciliary muscles)
  3. Pupils constrict (sphincter of iris)
    (all are independent of one another, one can be affected and others not).
67
Q

In order for dilation to occur, what must the parasymp and symp systems do?

A

Parasymp must be inhibited: sphincter relaxes

Symp must be excitied: dilator (radial muscle contracts).

68
Q

is the sphincter or dilator more strong in response?

A

Sphincter

69
Q

Drugs that can dilate?

A 
Parasymp antagonists: (relax parasymp sys, affects accommodation): Tropicamide and Cyclopentolate (causes blurriness for a while)
Sympathetic Agonists (does not affect accommodation): phenylephrine
70
Q

Darker iris’s need stronger or weaker drops? those with diabetes?

A

stronger.

weaker.

71
Q

What is a direct response?

A

light shown in one eye, watch for response in that same eye.

72
Q

What is a consensual response?

A

light shown in one eye, watch for response in other eye.

73
Q

If patient is healthy the direct and consensual responses in both eyes should be?

A

same magnitude, briskness and latency.

74
Q

You can evaluate integrity of afferent pupillary reflex pathway by doing what? afferent input in each eye should be what?

A

swinging a light between the eyes.

symmetrical.

75
Q

With the swinging flashlight test, the one sec test is good for what? 3 sec?

A

1: for large RAPDs
3: smaller RAPD but harder to see responses

76
Q

Is it normal for the eye to dilate a little and then constrict when doing the swinging flashlight test?

A

yes, due to hippus.

77
Q

Define amaurotic

A

Blind eye

78
Q

Muscles Paresis is? Paralysis?

A

Paresis: mild/moderate muscle weakness
Paralysis: severe or complete loss of motor function

79
Q

CN 3 innervates which muscles?

A

IR, IO, MR, SR, LPS and sphincter or iris.

80
Q

Hirschberg reflex is what? What is the normal result? if corneal relfexes differ between the two eyes what is most likely happening?

A

Reflection of cornea. White reflection seen in the middle of pupil or slightly nasal.
Strabismus.

81
Q

If hirschberg reflex is observed further out what is happening? if it is observed further in?

A

Eye is turned in therefore esotropia

Eye is turned out therefore exotropia

82
Q

If children experience discomfort or pain in the EOM testing most likely due to?

A

orbit disease (tumor).

PPO 1a (11 decks)

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