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OPT 662 > Exam 4 -- Complete and Randomized > Flashcards

Exam 4 -- Complete and Randomized Flashcards

1
Q

What are the five indications for an EOG?

A 
Retinitis Pigmentosa
Siderosis Bulbi
Vitelliform Dystrophy (Best Disease)
Fundus Favimaculatis (Stargardt Disease)
Chloroquine (Plaquenil) Retinopathy
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2
Q

Between apperceptive and associative agnosia, which is more severe?

A

Apperceptive.

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3
Q

________ stereo cells make up 20% of disparity detectors

A

Tuned inhibitory (fine)

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4
Q

Fine stereo cells are sensitive to specific disparities, up to what point?

A

Up to 1 degree.

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5
Q

When tested at 16 cpd, a 70 year old patient will require how much more contrast than a 20 year old patient?

A

Three times more contrast

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6
Q

What is the resting potential of the front of the eye?

A

About 6 mV

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7
Q

________ stereo cells make up 50% of disparity detectors

A

Tuned excitatory (fine)

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8
Q

Blindsight is when a patient is blind but can accurately point to the location of a visual stimulus or report the direction of motion. What is the classic explanation for the location of damage that causes blindsight? Where does the damage more likely occur?

A

Classic explanation is superior colliculus; reality is probably damage to V1 that leaves spared “islands”.

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9
Q

With an optic nerve disease such as glaucoma, would a focal PERG give a normal or abnormal result?

A

Abnormal

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10
Q

The Inferior Temporal area (IT) is also known as?

A

V4

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11
Q

With a macular lesion, would a standard ERG give a normal or abnormal result?

A

Normal

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12
Q

Hemispatial neglect is usually caused by a lesion in which area of the brain, on which side?

A

Inferior parietal lobe, right side (so left visual field affected).

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13
Q

What is Usher syndrome?

A

RP + deafness

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14
Q

Complex cortical cells respond to what kind of stimulus?

A

Unidirectional movement.

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15
Q

Damage to which area is thought to cause apperceptive agnosia?

A

Right parietal lobe.

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16
Q

Which of the extra striate cortices is the end of the parvocellular stream?

A

V4

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17
Q

Comparing a standard scotopic ERG to a normal photopic ERG, which is faster?

A

Photopic is faster

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18
Q

List each of the stops that information from magno cells in the LGN passes through on its way to V5/MT.

A
  1. Layer 4C-alpha in V1
  2. Layer 4B in V1
  3. Thick dark stripes in V2
  4. V5/MT
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19
Q

In amblyopia, would a focal PERG give a normal or abnormal result?

A

Normal

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20
Q

What are the three clinical applications of an ERG?

A

Assessing the patency of the retina and choroid, locating the site of damage, and separating damage to rods vs cones

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21
Q

_______________ is a reduction in pereceived object size and can lead to teleopsia.

A

Micropsia

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22
Q

Projections to the extrastriate area originate in particular from which layers of V1?

A

Layers 2/3

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23
Q

Comparing a standard scotopic ERG to a normal photopic ERG, which is slower?

A

Scotopic is slower

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24
Q

True or false: simple and complex cortical cells are sensitive to the length of a stimulus (they have end stops).

A

True.

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25
Q

Macular lesion, retinitis pigmentosa, optic nerve disease (such as glaucoma), amblyopia, and hysteria/malingering. For which of these conditions would VEP show a normal result?

A

Only hysteria/malingering would show a normal result.

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26
Q

What age range is considered the critical period of visual development, during which time amblyopia can develop?

A

6 months to 2 years.

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27
Q

What are the three types of amblyopia? Which is most severe? Which is least severe?

A

Deprivational, strabismic, and refractive. Deprivational is most severe, refractive is least severe.

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28
Q

The percentage of people with stereoacuity thresholds equal or better than 85 arcseconds decreases with age. According to the study cited in the presentation, what percentage of older people had full (20 arcsec) stereopsis, and what percentage had no stereopsis?

A

27% had full stereopsis, 29% had no stereopsis

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29
Q

In order to “tease out” a VEP wave from background noise, you have to know when to look for it. This coresponds to the amount of time between the light being flashed to the signal arriving at the striate cortex, which is how long?

A

80 ms

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30
Q

The antidepressant trazodone can cause which visual hallucinations?

A

Palinopsia and polyopia

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31
Q

Which is more common, congenital prosopagnosia or acquired prosopagnosia?

A

Congenital.

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32
Q

What is the average refractive error at age 2.5 months?

A

+2.50

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33
Q

There is a regular shift in orientation sensitivity as you move along the surface of the cortex. A complete circular set of orientation edge detectors is called what?

A

Hypercolumn

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34
Q

Suppose you are testing a nonverbal patient and would like to know whether the Rx you’ve found improves their VA. You run a VEP without the Rx, then again with the Rx. How do you expect the amplitude of the VEP to change if the Rx does indeed improve VA?

A

Amplitude should increase (increases with sharper retinal image).

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35
Q

In retinitis pigmentosa, would a standard ERG give a normal or abnormal result?

A

Abnormal

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36
Q

The Middle Temporal are (MT) is also known as?

A

V5

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37
Q

Macular lesion, retinitis pigmentosa, optic nerve disease (such as glaucoma), amblyopia, and hysteria/malingering. For which of these conditions would EOG show a normal result?

A

All would be normal except retinitis pigmentosa.

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38
Q

With an optic nerve disease such as glaucoma, would a standard ERG give a normal or abnormal result?

A

Normal

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39
Q

True or false: a macular hole would affect a standard flicker ERG.

A

False; the standard ERG tests the whole retina. You’d have to use a focal flicker ERG in order to see the effect of a specific area of the retina.

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40
Q

What are the five stages of Best Disease?

A
  1. Previtelliform
  2. Vitelliform
  3. Pseudohypopyon
  4. Vitelliruptive
  5. Atrophic
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41
Q

On a transient VEP, you expect to see three positive deflections and three positive deflections. Which of the positive deflections is the largest? Which of the negative deflections is the largest?

A

Positive #2 is the largest; negative #3 is the largest

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42
Q

Base out makes the binocular image look _______ (smaller/larger).

A

Smaller

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43
Q

_______________ is an enlargement of objects seen and can lead to pelopsia.

A

Macropsia

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44
Q

With an optic nerve disease such as glaucoma, would an EOG give a normal or abnormal result?

A

Normal

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45
Q

What is the average refractive error at age 3 years?

A

+1.00

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46
Q

In retinitis pigmentosa, would an EOG give a normal or abnormal result?

A

Abnormal

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47
Q

Macular lesion, retinitis pigmentosa, optic nerve disease (such as glaucoma), amblyopia, and hysteria/malingering. For which of these conditions would standard ERG show an abnormal result?

A

Only retinitis pigmentosa would show as abnormal.

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48
Q

What cell type is thought to cause the c-wave on an ERG?

A

RPE cells

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49
Q

What is the average refractive error at age 1 year?

A

+1.50

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50
Q

The Arden Ratio for a patient with ocular albinism is above what value?

A

300%

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51
Q

What kind of scotoma is often found in a patient with RP?

A

Ring scotoma

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52
Q

What is the average refractive error at age 6 months?

A

+1.75

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53
Q

How long does a light rise take to reach its peak on an EOG?

A

10-15 minutes.

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54
Q

In which layer of V1 does figure-ground and binocularity begin?

A

Layer 2

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55
Q

If you wanted to test the entire retina function, you would use a __________ ERG. If you wanted to test a specific area, you would use a __________ ERG.

A

Entire retina: full-field. Specific area: focal.

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56
Q

Macular lesion, retinitis pigmentosa, optic nerve disease (such as glaucoma), amblyopia, and hysteria/malingering. For which of these conditions would EOG show an abnormal result?

A

Only retinitis pigmentosa would show as abnormal.

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57
Q

A full-field (standard, flash) ERG is derived primarily from the ___________ (inner/outer) retina.

A

Outer.

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58
Q

Macular lesion, retinitis pigmentosa, optic nerve disease (such as glaucoma), amblyopia, and hysteria/malingering. For which of these conditions would focal PERG show a normal result?

A

Only hysteria/malingering and amblyopia would show a normal result.

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59
Q

At what age is contrast sensitivity up to adult-like levels?

A

9 years

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60
Q

What is the name of the phenomenon where a visual immage recurrently appears after the stimulus has disappeared?

A

Palinopsia

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61
Q

True or false: with optic neuritis, VEP latency will increase or decrease as the patient undergoes remissions and exacerbations.

A

False; once the latency increases, it stays increased.

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62
Q

With hysteria or malingering, would an EOG give a normal or abnormal result?

A

Normal

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63
Q

What are the light sensitive components of the EOG?

A

Photoreceptors

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64
Q

In amblyopia, would a VEP give a normal or abnormal result?

A

Abnormal

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65
Q

Which layer of V1 sends fibers to the superior colliculus?

A

Layer 5

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66
Q

Suppose you did a pattern ERG three times: once stimulating the fovea and the periphery, once stimulating just the fovea, and once stimulating just the periphery. When would the amplitude of the PERG be relatively high, and when would it be relatively low?

A

The amplitude of a PERG is relative to the area of the retina stimulated, so the amplitude would be high when stimulating both the fovea and periphery. Stimulating only the fovea but not the periphery (and vice versa) would have a decreased amplitude.

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67
Q

The magnocellular layers in the LGN synapse with which layer of V1?

A

4C-alpha

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68
Q

A standard (flash, full-field) ERG shows positive and negative deflections. Which wave, a or b, has a negative deflection? Which cell type causes it?

A

A-wave has a negative deflection and is caused by the photoreceptors.

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69
Q

How could a patient be blind but have a normal VEP?

A

If the damage causing blindness is located downstream of V1, VEP would be normal (since it focuses between the optic nerve head and V1).

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70
Q

A standard (flash, full-field) ERG shows positive and negative deflections. Which wave, a or b, has a positive deflection? Which cell types causes it?

A

B-wave has a positive deflection and is caused by the Mueller and/or bipolar cells.

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71
Q

True or false: a formed hallucination is a sensory perception in the absence of an external stimulus.

A

True. This is what distinguishes it from visual illusions, which are misperceptions of a visual stimulus.

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72
Q

With an optic nerve disease such as glaucoma, would a VEP give a normal or abnormal result?

A

Abnormal (though it may be normal early on in the disease)

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73
Q

The parvocellular layers in the LGN synapse with which layer of V1?

A

4C-beta (also 4A)

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74
Q

The Arden Ratio is the light rise divided by the dark trough. What are normal values?

A

180% to 250%

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75
Q

Hallucinations caused by which condition often cause inanimate objects to be viewed as living beings or parts of living beings?

A

Parkinson disease.

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76
Q

Forced preferential looking is a way to measure a child’s acuity using grating patterns. What percent of correct performance indicates the level of the child’s VA?

A

75%

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77
Q

Macular lesion, retinitis pigmentosa, optic nerve disease (such as glaucoma), amblyopia, and hysteria/malingering. For which of these conditions would standard ERG show a normal result?

A

All would be normal except retinitis pigmentosa.

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78
Q

The percentage of people failing the D-15 test increases with age, primarily due to what kind of defects?

A

Tritan defects

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79
Q

What would the cortical dominance histogram look like for a patient with alternating exotropia?

A

It would be skewed toward 1 and 7, with little to no input to the other columns (since there is never concurrent input by both eyes)

80
Q

During the vitelliform stage of Best Disease, the lesions has an egg-yolk appearance and are usually centered on the macula and can be multifocal. How bad is VA in this stage?

A

VA is usually in the 20/20 to 20/40 range.

81
Q

Simple cortical cells respond to what kind of stimulus?

A

Orientation. They can be on-off, or edge detectors.

82
Q

_______________ is the transfer of visual images from one half of the visual field to the other.

A

Visual allesthesia.

83
Q

What is the name of the condition in which blind patients experience vivid, complex visual hallucinations?

A

Charles Bonnet Syndrome

84
Q

Plaquenil is used for autoimmune diseases like lupus. What is the name of the sign that can be seen on OCT of a patient with Plaquenil retinopathy?

A

Flying saucer sign

85
Q

True or false: ERG on a patient with Leber Congenital Amaurosis would be a flat line.

A

True.

86
Q

There are two categories of coarse stereo cells: far and near. Which of these is excited if an object is beyond the point of fixation and inhibited if the object is closer than the point of fixation?

A

Far coarse cells. Near coarse cells are the opposite (excited to nearer than fixation, inhibited to further than fixation).

87
Q

Moderate and higher uncorrected astigmatism during childhood causes what kind of amblyopia? How would you treat it?

A

Meridional amblyopia; treat with full-time wear of full correction of all cylinder measured on wet retinoscopy.

88
Q

Which cells in the visual cortex have axons that usually do not leave the cortex?

A

Stellate

89
Q

Cortical blindness is the loss of vision in V1 despite intact eyes, optic nerves, and optic radiations. What is the name of the condition if patients are unaware of their blindness? What are some causes of cortical blindness?

A

Anton Syndrome. Cortical blindness can be caused by birth defects, trauma, Creutzfeld-Jakob Disease, and epilepsy meds.

90
Q

True or false: hypercomplex cells are real.

A

False; they are not real. They were proposed by Hubel and Wiesel, but turned out to be incorrect.

91
Q

___________ stereo cells make up 30% of disparity detectors.

A

Coarse

92
Q

Focal epileptic hallucinations are most often caused by seizures in what area?

A

Posterior temporal-parietal junction. Focal epileptic seizures can also cause nystagmus, macropsia, and kinetopsia.

93
Q

If you want to know if the fovea is working, which part of the VEP do you care more about: the amplitude or the latency?

A

Amplitude.

94
Q

Kollner’s Rule recap: conditions in the inner retina and pathways cause what type of color vision anomaly? What conditions fall into these categories?

A

Inner retina/pathway cause red-green defects.
Inner retina: Leber’s optic atrophy (aka Leber’s Hereditary Optic Neuropathy) and toxic amblyopia (aka toxic optic neuropathy).
Pathway: various lesions

95
Q

Development of contrast sensitivity, vernier acuity, and grating acuity takes place beginning around what age?

A

Over 32 months

96
Q

What is the average refractive error at age 4 years?

A

+1.25

97
Q

Comparing a standard scotopic ERG to a normal photopic ERG, which is smaller?

A

Photopic is smaller

98
Q

Steady-state VEP is a type of flicker VEP, in that the resulting graph shows a sine wave (in normal patients). What is the most common frequency of the phase-reversing checkerboard pattern used?

A

20 Hz

99
Q

VEP can be used to objectively estimate both a patient’s VA and their contrast sensitivity by taking a series of measurements while changing the stimulus. In order to find the estimated VA or CS, you would then extrapolate from the line created by these measurements to what value?

A

Zero

100
Q

Development of stereopsis, scotopic sensitivity, photopic/scotopic luminosity, and CFF takes place around what age?

A

2 months to around 6 months

101
Q

Ocular dominance columns respresent neurons that get the majority of their input from _________ (one/both) eye(s).

A

One.

102
Q

How much anisometropia is typically required for symptomatic aniseikonia?

A

2.00 D or more

103
Q

In retinitis pigmentosa, would a VEP give a normal or abnormal result?

A

Abnormal (though it may be normal early on in the disease)

104
Q

What is the average monocular VA at age 2.5 months?

A

20/280

105
Q

True or false: concious attention enhances a multifocal VEP.

A

True.

106
Q

True or false: the limits of contrast sensitivity before age 1 year is due to immaturities in the cortex.

A

False; the limitation is due to immaturities in the retina, not the cortex.

107
Q

Which of the extra striate cortices is the end of the magnocellular stream?

A

V5

108
Q

What percent in size difference is needed before aniseikonia causes symptoms? To what percent is the Aniseikonia Inspector Software accurate?

A

2% size difference needed for symptoms; Aniseikonia Inspector accurate to 0.1%

109
Q

Damage to which area of the brain can result in akinetopsia?

A

V5

110
Q

Dark adaptation in older individuals takes longer than in younger people. This is affected by senile miosis. How much does pupil size shrink per decade of life?

A

0.5 mm

111
Q

Name some of the causes of Balint Syndrome.

A

CJD, perinatal hypoxia, nitroglycerin, Alzheimer’s disease

112
Q

Projections to the lower visual centers (LGN, pulvinar) original in particular from which layer of V1?

A

Layer 6

113
Q

True or false: the diameter of the visual field changes little with age, but decreases dramatically with age with split attention.

A

True.

114
Q

In which stage of Best Disease does the yellow material break through the RPE and accumulate in the subretinal space? What condition may this appear like?

A

Pseudohypopyon; may appear like central serous choroidopathy

115
Q

In amblyopia, would an EOG give a normal or abnormal result?

A

Normal

116
Q

What is the name of the syndrome if a patient has RP and deafness?

A

Usher Syndrome

117
Q

What percent of the retinal area is the fovea, and what percent of the striate cortex is devoted to foveal vision?

A

0.01% of retinal area; 8% of striate cotex.

118
Q

With hysteria or malingering, would a VEP give a normal or abnormal result?

A

Normal

119
Q

List each of the stops that information from parvo cells in the LGN passes through on its way to V4/IT.

A
  1. Layer 4C-beta in V1
  2. Blobs (for color), interblobs for detail (in V1)
  3. Blobs to thin dark stripes in V2; interblobs to pale stripes in V2
  4. V4/IT
120
Q

It is thought that dementia-induced hallucinations and caffeine-induced hallucinations occur because of ________________.

A

Poor perfusion

121
Q

_______________ is the perception that objects are farther away than they really are, and can result fro micropsia.

A

Teleopsia

122
Q

How long does a dark trough take to reach its minimum on an EOG?

A

8 minutes

123
Q

What is the human peak of contrast sensitivity, both in cpd and Snellen equivalent? By what age is this peak present?

A

Peak is 4 cpd (20/150 Snellen). This peak is present by age 4 years.

124
Q

Micropsia and teleopsia are caused by defects in which part of the brain? (Hint: it’s the same location as neglect and allesthesia.)

A

Parietal lobe

125
Q

If you were to run both a photopic flicker ERG and a scotopic flicker ERG on an RP patient, which would have the more obvious deficit?

A

Scotopic.

126
Q

What changes happen to the VEP of a person with an optic neuropathy, compared to normal? Which optic neuropathy is the one we tend to think about most?

A

The latency increases. Glaucoma is the optic neuropathy we tend to think about.

127
Q

The Medial Superior Temporal area (MST) is also known as?

A

V3

128
Q

What is the name of the phenomenon where structured geometric figures occur, often in a repetitive pattern?

A

Photopsia

129
Q

What VF testing would you order for a patient on Plaquenil?

A

A 10-2 central VF

130
Q

Dominance slabs and edge detectors are found in which areas?

A

V1 and V2

131
Q

True or false: older patients have reduced CFFs, particularly at intermediate and high spatial frequencies.

A

True.

132
Q

The koniocellular layers in the LGN synapse with which layers of V1?

A

Layers 2 and 3

133
Q

What is the name of the condition that can occur with a metallic foreign body, causing the eyes to turn a rusty color and the pupil to dilate?

A

Siderosis Bulbi

134
Q

True or false: even though the macula is normal looking (or near normal) in previtelliform stage of Best Disease, the EOG is still abnormal.

A

True.

135
Q

Damage to which area is thought to cause associative agnosia?

A

Left temporal-occipital junction.

136
Q

Which type of ERG is used for inner retina and ganglion cell function, PERG or mfERG?

A

PERG

137
Q

What is the amplitude of the background “brain noise” when you’re doing a VEP?

A

60 microvolts

138
Q

True or false: VEP overestimates the VA for infants, compared to the values found with forced-preferential looking.

A

True.

139
Q

Changes in a series of pictures are harder to see when they are presented side-by-side, but are easier to see when presented sequentially. Which retinal cell helps to spot the changes with sequential viewing?

A

Amacrine.

140
Q

Adult vitelliform macular dystrophy resembles Best Disease, but can be distinguished by its later age of onset, smaller lesion size, and what other feature?

A

Normal EOG finding.

141
Q

The early receptor potential (ERP) is a small portion of the ERG wave that is not seen clinically, since it requires a very bright light. What part of the retina causes the ERP?

A

Primarily the cones.

142
Q

Macular lesion, retinitis pigmentosa, optic nerve disease (such as glaucoma), amblyopia, and hysteria/malingering. For which of these conditions would focal PERG show an abnormal result?

A

All would be abnormal except hysteria/malingering and amblyopia.

143
Q

What is the average refractive error at age 2 years?

A

+1.25

144
Q

What is the average monocular VA at age 6 months?

A

20/110

145
Q

How would deprivational amblyopia affect the ocular dominance histogram?

A

The histogram would be skewed toward the eye without the deprivation (i.e., if a patient had a left congenital cataract, measuring the ocular dominance of the right striate would show skewing toward ipsilateral (7), while measuring the ocular dominance of the left striate would show skewing toward contralateral (1)).

146
Q

Base in makes the binocular image look _______ (smaller/larger).

A

Larger

147
Q

Comparing a standard scotopic ERG to a normal photopic ERG, which is bigger?

A

Scotopic is bigger

148
Q

Which of the extra striate cortices is for color and facial/object recognition?

A

V4

149
Q

In amblyopia, would a standard ERG give a normal or abnormal result?

A

Normal

150
Q

_______________ is the perception that objects are closer than they really are, and can result from macropsia.

A

Pelopsia

151
Q

What is the average monocular VA at age 4 years?

A

20/20

152
Q

True or false: a cortically-blind infant can have an optokinetic nystagmus.

A

True. The OKN is controlled by the cerebellum and the pretectum, not the cortex.

153
Q

What is the average monocular VA at age 3 years?

A

20/30

154
Q

Which of the extra striate cortices is for binocular vision?

A

V2

155
Q

What is the name of the phenomenon where a person sees the same object multiple times (at the same time)?

A

Polyopia

156
Q

True or false: damage that causes prosopagnosia is usually bilateral, but is occasionally to the right hemisphere only.

A

True.

157
Q

Where are the disparity cells of our visual system located?

A

V2 for complex cells, V3 for local motion.

158
Q

What would cause an erroneously high Arden Ratio?

A

If the patient can’t see the end points.

159
Q

Which of the extra striate cortices is for local motion (like pursuits)?

A

V3

160
Q

In which stage of Best Disease does the lesion become like a scrambled egg in appearance? How bad can VA get in this stage?

A

Vitelliruptive; VA no worse than 20/100

161
Q

Which of the extra striate cortices is for global motion (like saccades)?

A

V5

162
Q

Which type of ERG is used for outer retina (photoreceptors and bipolar) function, PERG or mfERG?

A

mfERG

163
Q

A shortage of inhibition due to which neurotransmitter might underlie age-related visual deficits?

A

GABA

164
Q

What is the amplitude of a typical VEP?

A

5 microvolts

165
Q

Kollner’s Rule recap: conditions in the media or in the outer retina cause what type of color vision anomaly? What conditions fall into these categories?

A

Media/outer retina cause blue-yellow defects.
Media: nuclear sclerosis.
Outer retina: ARMD and diabetic retinopathy

166
Q

Which cells in the visual cortex have axons that commonly leave the cortex?

A

Pyramidal

167
Q

A flicker ERG uses a 30 Hz light and looks like a sine-wave. Which type of retinopathy might cause the amplitude to decrease during the ERG?

A

Outer retina disease like diabetic retinopathy.

168
Q

In retinitis pigmentosa, would a focal PERG give a normal or abnormal result?

A

Abnormal

169
Q

With a macular lesion, would an EOG give a normal or abnormal result?

A

Normal

170
Q

How many categories of ocular dominance are there? Which category consists of ipsilateral-only input (in a binocularly normal patient)? Which consists of contralateral-only input?

A

7 categories. 7 is ipsilateral, 1 is contralateral.

171
Q

With a macular lesion, would a focal PERG give a normal or abnormal result?

A

Abnormal

172
Q

Which optic neuropathy is often tested for with PERG?

A

Glaucoma.

173
Q

True or false: in a VEP on a patient with ocular albinism, the amplitude would be decreased and the latency would be decreased.

A

False; the latency would be normal since the myelination has not been affected. Amplitude would be decreased since the patient has abnormal crossing at the optic chiasm, which decreases their VA (somehow…)

174
Q

With hysteria or malingering, would a standard ERG give a normal or abnormal result?

A

Normal

175
Q

What are the light insensitive components of the EOG?

A

RPE, cornea, lens, etc, but not the photoreceptors. These establish the dark trough.

176
Q

What is the average monocular VA at age 1 month?

A

20/640

177
Q

True or false: the voltage of the eye is greater in the light than it is in the dark.

A

True.

178
Q

What kind of inheritance pattern does Leber’s Congenital Optic Neuropathy exhibit? What kind of visual field defect might a patient with this condition exhibit?

A

Mitochondrial (mother to child). VF defect might be cecocentral.

179
Q

Best Disease is inherited in what fashion?

A

Autosomal dominant

180
Q

Reduction to the inferior longitudinal fasciculus has been associated with what type of agnosia?

A

Prosopagnosia.

181
Q

What would cause an erroneously low Arden Ratio?

A

If the patient closes their eyes or looks away.

182
Q

True or false: in the dark, the front of the eye is more negatively charged than the back of the eye?

A

False; the front of the eye is more positive than the back of the eye.

183
Q

What is the average monocular VA at age 1 year?

A

20/90

184
Q

In the final stage of Best Disease, atrophic, the small macular scar that remains can cause VA to drop below what level?

A

20/200

185
Q

Binocular summation in a normal patient would cause an increase in the patient’s VEP when testing binocularly, compared to monocular VEP. By what factor does VEP increase? Patients with what condition will deviate from this pattern?

A

1.4 (square root of how many eyes we have). Amblyopes will not have an increase of 1.4 in the amplitude of their dominant eye VEP to their binocular VEP.

186
Q

What part of the retina is often affected first in a patient with RP? Which visual field?

A

Inferior retina, superior visual field.

187
Q

Macular lesion, retinitis pigmentosa, optic nerve disease (such as glaucoma), amblyopia, and hysteria/malingering. For which of these conditions would VEP show an abnormal result?

A

All would be abnormal except hysteria/malingering. (Note: retinitis pigmentosa and glaucoma may have normal VEP early in the disease)

188
Q

Suppose you did a VEP three times: once stimulating the fovea and the periphery, once stimulating just the fovea, and once stimulating just the periphery. When would the amplitude of the PERG be relatively high, and when would it be relatively low?

A

The amplitude of a VEP is relative to the amount of fovea stimulated, since a large part of the striate cortex is devoted to foveal vision. So stimulating fovea and periphery would have a high amplitude, but so would stimulating just the fovea. Stimulating just the periphery would have a very low amplitude.

189
Q

What is the average monocular VA at age 2 years?

A

20/60

190
Q

With a macular lesion, would a VEP give a normal or abnormal result?

A

Abnormal

191
Q

Macropsia and pelopsia might be caused by defects in which part of the brain? (Hint: it’s the same location as associative agnosia.)

A

Temporal-occipital junction

192
Q

True or false: R/G color vision development starts around age 2 and may continue until adolescence.

A

True.

193
Q

With hysteria or malingering, would a focal PERG give a normal or abnormal result?

A

Normal

194
Q

Balint Syndrome is a triad of findings. What three findings are they?

A

Simultagnosia, oculomotor ataxia, and oculomotor apraxia.

195
Q

List the average refractive errors for the following ages:

2.5 months
6 months
1 year
2 years
3 years
4 years
A 
2.5 months: +2.50
6 months: +1.75
1 year: +1.50
2 years: +1.25
3 years: +1.00
4 years: +1.25
196
Q

List the average visual acuities for the following ages:

1 month
2.5 months
6 months
1 year
2 years
3 years
4 years
A 
1 month: 20/640
2.5 months: 20/280
6 months: 20/110
1 year: 20/90
2 years: 20/60
3 years: 20/30
4 years: 20/20

OPT 662 (8 decks)

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