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Methods BLOCK 4 > Amblyopia II > Flashcards

Amblyopia II Flashcards

1
Q

What are the types of refractive amblyopia

A
  • meridonial
  • isoametropic
  • anisometropic
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2
Q

Meridional amblyopia

A

Due to uncorrected high astigmatism in one or both eyes

-can be easily missed due to the orientation of the astigmatism (some kids can squint or compensate)

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3
Q

Isoametropic amblyopia

A
  • caused by very high refractive error in both eyes
  • so high that a clear retinal image cannot be obtained
  • results in a bilateral decrease in VA
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4
Q

A 6 yo Caucasian male with +7.50D of uncorrected hyperopia will have..

A 
Difficulty focusing (accommodating) to form a clear image at distance and/or near 
-even after proper correction for this child, VA may initially stay reduced OU. Brain needs time to adjust
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5
Q

What can high hyperopia cause and why?

A

Esotropia, from accommodating so much. Not always the case especially for kids who haven’t started school yet

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6
Q

Anisometropic amblyopia

A

Normal refractive error with good VA in one eye and a significant error and reduced VA in the other eye
-“that’s my bad eye”

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7
Q

Which type of amblyopia may be more difficult for parents to detect and why

A

Anisometropic amblyopia because the child relies heavily on the better seeing eye

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8
Q

What are some mistakes the Dr could make that would cause them to miss this diagnosis

A
  • VA done with both eyes open
  • not making sure that each eye is properly covered to prevent peeking
  • skipping parts of the exam
  • assumptions that little children cant have visual impairments
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9
Q

What are some tests that should be done if you suspect amblyopia

A
  • cover test
  • stereo
  • retinoscopy
  • ophthalmoscopy
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10
Q

Uncorrected refractive error causes a ________ that prevents the brain form getting clear information via the visual pathway

A

Constant blur

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11
Q

In a properly functioning visual pathway, the ___________ of the ________________ responds to high spatial frequency stimulation

A
  • parvocellular layer

- lateral geniculate nucleus

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12
Q

Parvocellular layers in the poorer seeing eye

A

Not stimulated by blur

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13
Q

When is the effect of blur highest?

A

In the critical period of development of the visual system (in the first years of life)

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14
Q

Hyperopic anisometropia

A

Amblyopia resulting from a difference of hyperopia between the 2 eyes is common

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15
Q

What is the minimum of hyperopic anisometropia that can be problematic?

A

As little as +1.00D

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16
Q

What can as little as +1.00D of hyperopic anisometropia affect?

A
  • proper fusion at distance and near

- cause amblyopia in the more hyperopic eye

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17
Q

If both eyes are hyperopic

A

The less hyperopic eye can maintain control, keep some motor and sensory function

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18
Q

What is something that could could develop from hyperopic anisometropia

A

Esotropia

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19
Q

What two entrance tests could be affected with hyperopic anisometropia?

A
  • stereopsis

- W4D could show fusion depending on the severity of the amblyopia, you could also pick up a central scotoma

20
Q

Myopic anisometropia

A

High unilateral myopia with lesser myopia in the other eye

21
Q

If they have a significant difference in refraction between the two eyes

A

Most definitely amblyopia

22
Q

Moderate myopic anisometropia (less than 5D)

OD: -0.75 Ds (used for distance)
OS: -3.25 Ds (advantage for near)

A

Amblyopia will likely NOT develop in this case because both eyes attain clarity at either distance or near **

23
Q

Form deprivation

A

Obstruction of the line of sight that prevents a clear image to form on the retina
-can occur in one or both eyes

24
Q

Physical obstructions that can lead to amblyopia include:

A
  • congenital cataracts
  • ptosis
  • traumatic cataract
  • corneal opacity
  • vitreous opacity
  • vitreous hemorrhage (shaken baby syndrome)
25
Q

Which entrance test determines the presence of strabismus?*****

A

COVER TEST **

26
Q

Strabismus

A

This occurs when the visual axes of both eyes do not intersect at fixation

27
Q

Reasons for strabismus

A
  • early onset
  • accommodative strabismus (because if hyperopia)
  • result of stroke, thyroid, retinal disease or other systemic disease
28
Q

How is strabismus/heterotropia/tropia classified

A

By the direction of the non fixating eye

29
Q

Types of strabismus

A
  • early onset
  • accommodative
  • acquired
30
Q

The more time that there is equal VA and bionocularity before the strabismic disruption….

A

The better the chances that binocularity can be reestablished

31
Q

Strabismus and past history

A
  • occlusion therapy
  • glasses or contacts
  • past surgeries

Helps making a plan and prognosis

32
Q

Strabismus prognosis

A

The earlier the intervention after onset, the less chance of sensory adaptation

33
Q

Sensory adaptations

A
  • amblyopia
  • scotoma/suppression
  • anomalous correspondence
  • normal correspondence
34
Q

What does steropsis imply

A

Better prognosis

35
Q

Strabismus prognosis is worse with

A
  • esotropia
  • anomalous correspondence
  • constant unilateral strabismus
36
Q

With strabismic amblyopia, there is a spatial uncertainty and difficulty with localization, causing

A
  • monocular adaptations
  • anomalous correspondence
  • anomalous oculomotor behaviors
37
Q

________ pattern is affected and eye movement __________ is affected in strabismic amblyopia

A

Fixation

Accuracy

38
Q

Spatial uncertainty

A

Causing patients to read out of order or drop letters, after likely correctly identifying the first and last ones

39
Q

There is a risk of _________ to the non amblyopic eye

A

Injury

40
Q

________ fixation can occur in strabismic amblyopia patients

A

Eccentric

41
Q

Eccentric retinal point

A

Assumes the role of the fovea and becomes straight ahead where the visual axes starts

42
Q

What is clearly reduced with an eccentric non-fovea point?

A

VA

43
Q

What kind of strabismus is more likely to cause amblyopia?

A

Unilateral

44
Q

What kind of strabismus is less likely to lead to amblyopia?

A

Intermittent strabismus or an alternating (even constant)

45
Q

Consider a 75 yo asian female with a constant left esotropia with a right hypertropia due to a 3rd nerve palsy that occurred at the age of 73. Did this patient previously have binocularity? What is the chance of amblyopia in this patient?

A

Low, not in the critical period

46
Q

Consider a 12 month old caucasian male with a congenital right esotropia that has never seen an eye doctor. Did this patient previously have binocularity? Could this child have amblyopia?

A
  • no

- yes

Methods BLOCK 4 (7 decks)

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