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Motility Block 11 > Other Forms Of Strabismus > Flashcards

Other Forms Of Strabismus Flashcards

1
Q

Mechanical restrictive deviations

A

EOM is tethered or a systemic diseases reduces the elasticity of one or more muscles

  • incomitant, nonpareil deviations
  • congenital or acquired mechanism restrictions
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2
Q

Congenital mechanically restrictive deviations

A

Duane syndrome
Browns syndrome
Fibrosis syndrome

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3
Q

Acquired mechanically restrictive deviations

A

Thyroid myopathy

Deviations secondary to trauma

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4
Q

Is duanes congenital or acquired

A

Mainly congenital but can be acquired

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5
Q

Common characterisitics of mechanical restrictive deviations

A
  • gross limitations of ocular movement in one or more directions of gaze
  • often present a small deviation or orthophoria in primary posirion
  • frequent preservation of normal bino vision aided by compensatory head movement
  • positive forced duction
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6
Q

Alternate CT in mechanically restriuvice deviations

A

May not provide accurate results when measuring the magnitude of deviation

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7
Q

Best test for mechanically restrictive deviations

A

Maddox rod or prism bar over the affected eye may be beneficial to measure int the deviations. If both eyes are srestricted, hirschbirg or krimsky may be best

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8
Q

Characterized by limitations in abduction, adduction, or both

A

Duanes syndrome

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9
Q

How do you tell what type of dueanse it is

A

Type correspondence to the number of Ds

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10
Q

Type I Duanes syndrome

A

Most common
Limited ABDuction
A patient with limited abduction in the absence of a significant strabismus in primary position should be considered Duane syndrome until proven otherwise

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11
Q

Type 2 Duanes syndrome

A

Least common

Limited ADDuction

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12
Q

Type 3 Duanes

A

Limited in ABDuction and ADDuction

3 Ds= type 3

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13
Q

Characteristics of Duane’s syndrome

A
  • congenital
  • unilateral (85%)
  • no significant strabismus in primary gaze
  • globe retracts (enophthalmos) and eyelid fissure narrows on adduction
  • size of deviation increases toward the affected
  • may have A or V pattern
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14
Q

If there is a strabismus in primary gaze in Duanes

A

May have eso or head turn toward the effected side

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15
Q

What happens when they ADDuct in Duanes

A

Globe retracts nad eyelid fissure starts to narrow

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16
Q

Size of deviation in Duanes

A

Increases toward the affected side

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17
Q

A pattern

A

Eyes are out as they look down

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18
Q

V pattern

A

Eyes are out as they look up

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19
Q

Onset of Duanes

A

Sporadic onset is most common, uncommonly hereditary

-usually isolated disorder

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20
Q

Etiology of Duane;s syndrome

A

mechanical, anatomical, and innervation disorder

  • fibrotic LR or MR that is inserted too far posteriroly
  • studies have shown anomalous innervation
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21
Q

Anomalous innervation in Duanes

A

May be due to the absence of abducens nuclei and peripheral nerves of the affected side along with innervation of the LR with branches of the inferior division of CNIII

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22
Q

Binocularity on Duane

A

-most have a high level of binocularirty, typically orthophoric in primary position

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23
Q

Compensatory head posture in duanes

A

Depdneten on the amount of deviation in primary position

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24
Q

Amblyopia in Duane

A

Rare

-they have to have an abnormalirit in primary position to get this, Duenes does not

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25
Q

Diplopia in Duanes

A

Rare

-patients learn to ignore the extrafoveal image

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26
Q

Motility in Duanes

A

May see an up/downshoot elf the affected eye during ADDuction

  • mimics overaction of IO and/or SO
  • surgery may not help with the up/downshoot of the oblique muscles
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27
Q

Differential diagnosis of Duanes

A

Lateral rectus Palsy (6th nerve palsy)

  • absence of retraction with adduction
  • esotropic angle is typically larger with CN6 palsy
  • rarely have vertical anomalous movements
  • negative forced duction
28
Q

Patient with limited abduction in the absence of a significant strabismic deviation in primary position should be considered?

A

As DUANE SYNDROME until proven otherwise!!

29
Q

TX of Duanes

A

Surgical
-reserved for pts manifesting significant strabismus in primary position, marked head posture, or marked up/down shoot, and/or retraction of the globe in adduction, rarely improves abduction/adduction but improves field of bino vision

Prisms
-can be used to alleviate compensatory head postures

30
Q

What type of prism for left type I duanes

A

Left BO, right BI

Yoked prism

31
Q

Other names ofr Browns syndrome

A

SO tendon sheath syndrome

32
Q

Show restricted elevation ad addicted eye around the mid-horizontal plane

A

Brown’s syndrome

33
Q

Characteristics of Browns

A
  • majority unilateral
  • OD>OS
  • females>males
  • usually constant but can have intermittent episodes
34
Q

Etiology of Browns

A
  • presumed that the trochlea to the SO tendon insertion distance cannot be increased bracudse of mechanical causes
  • commonly due to a thickening of the SO tendon, cannot move through trochlea effectively

No innervation problems, just mechanical

35
Q

Browns: congenital or acquired?

A

Congenital

-CAN be acquired

36
Q

How can BRowns he acquired

A

Trauma, inflammatory disease processes, iatrogenic (surgery)

Usually due to injury or inflammation in the region of the trochlea

May improve over time

37
Q

Restricted elevation or absence of elevation in adduction that si the same on version and duction testing

A

Browns

38
Q

Forced duction on Browns

A

Positive

39
Q

Deviation in primary gaze on Browns

A

Minimal or none

40
Q

What kind of pattern in Browns

A

May have V pattern eso deviation in up gaze

41
Q

Audible click in Browns

A

May hear an audible click in elevation

42
Q

Compensatory head posture in Browns

A

Chin elevation and pointing toward opposite shoulder

-mild downshoot of affected eye in adduction

43
Q

Overaction of the ipsilateral SO in Browns

A

Absent

44
Q

Palpebral fissure in Browns

A

Widening

45
Q

Elevation in abduction for the affected eye in BRwons

A

Normal

46
Q

Where is the restricted elevation in browns

A

ONLY IN adduction

Eye gradually rotates from the adduction to abducted position, there is a corresponding increase in elevation

47
Q

Binocularity in browns

A
  • most have a high level of binocular ision when the eyes are in primary position or downgaze
  • many are orthophoric in primary position
  • amblyopia uncommon
  • ignoring rather than suppressing of the diplopia image most likely occurs in the affected position of gaze
48
Q

Differential diagnosis of Brown

A

Inferior oblique paresis

  • hypotropia in primary position
  • head tilt to the affected side along with a possible head turn and chin elevation
  • Pattern: exo in downgze
  • able to fulfill parks 3 step
49
Q

TX of brown

A
  • most do not require
  • recommended for those with either significantly hypotropia in primary position or compensatory head posture that is cosmetically displeasing
  • primary TX=surgery
  • secondary-BU yoked prism
  • vision therapy to improve elevation in adduction is usually unsuccessful
50
Q

Overall problem with Duanes syndrome

A

Mechanical restriction, anatomy issue, or innervation issue to LR

51
Q

Overall problem of Browns

A

SO tendon is thick

52
Q

Etiology of Duanes

A

Unable to adduct, abduct, or both

53
Q

Etiology of Browns

A

cant elevate in adduction

54
Q

Onset of Duanes

A

Congenital

55
Q

Onset of browns

A

Congenital or acquired

56
Q

Unilateral or bilateral: Duanes

A

Unilateral

57
Q

Unilateral or bilateral: Browns?

A

Unilateral

58
Q

Is there amblyopia in duanes

A

No

59
Q

Is there amblyopia in Browns

A

No

60
Q

Is there an diplopia in browns

A

No

61
Q

Is there any diplopia in duanes

A

No

62
Q

Head posture in duanes

A

TI: heads turned toward the affected side
T2: away from the affected side

63
Q

Head posture in browns

A

Chin elevation

64
Q

Lid changes in duanes

A

Narrow palpebral fissure

65
Q

Lid changes in browns

A

Widening of palpebral fissure

66
Q

Other characteristics of duanes

A

Globe retraction

Up/downshoot with adduction

67
Q

Other characteristics of browns

A

V pattern in upgaze

Motility Block 11 (4 decks)

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