Other Forms Of Strabismus

Question 1

Mechanical restrictive deviations

Answer 1

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

• incomitant, nonpareil deviations
• congenital or acquired mechanism restrictions

Question 2

Congenital mechanically restrictive deviations

Answer 2

Duane syndrome
Browns syndrome
Fibrosis syndrome

Question 3

Acquired mechanically restrictive deviations

Answer 3

Thyroid myopathy

Deviations secondary to trauma

Question 4

Is duanes congenital or acquired

Answer 4

Mainly congenital but can be acquired

Question 5

Common characterisitics of mechanical restrictive deviations

Answer 5

• 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

Question 6

Alternate CT in mechanically restriuvice deviations

Answer 6

May not provide accurate results when measuring the magnitude of deviation

Question 7

Best test for mechanically restrictive deviations

Answer 7

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

Question 8

Characterized by limitations in abduction, adduction, or both

Answer 8

Duanes syndrome

Question 9

How do you tell what type of dueanse it is

Answer 9

Type correspondence to the number of Ds

Question 10

Type I Duanes syndrome

Answer 10

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

Question 11

Type 2 Duanes syndrome

Answer 11

Least common

Limited ADDuction

Question 12

Type 3 Duanes

Answer 12

Limited in ABDuction and ADDuction

3 Ds= type 3

Question 13

Characteristics of Duane’s syndrome

Answer 13

• 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

Question 14

If there is a strabismus in primary gaze in Duanes

Answer 14

May have eso or head turn toward the effected side

Question 15

What happens when they ADDuct in Duanes

Answer 15

Globe retracts nad eyelid fissure starts to narrow

Question 16

Size of deviation in Duanes

Answer 16

Increases toward the affected side

Question 17

A pattern

Answer 17

Eyes are out as they look down

Question 18

V pattern

Answer 18

Eyes are out as they look up

Question 19

Onset of Duanes

Answer 19

Sporadic onset is most common, uncommonly hereditary

-usually isolated disorder

Question 20

Etiology of Duane;s syndrome

Answer 20

mechanical, anatomical, and innervation disorder

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

Question 21

Anomalous innervation in Duanes

Answer 21

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

Question 22

Binocularity on Duane

Answer 22

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

Question 23

Compensatory head posture in duanes

Answer 23

Depdneten on the amount of deviation in primary position

Question 24

Amblyopia in Duane

Answer 24

Rare

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

Question 25

Diplopia in Duanes

Answer 25

Rare | -patients learn to ignore the extrafoveal image

Question 26

Motility in Duanes

Answer 26

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

Question 27

Differential diagnosis of Duanes

Answer 27

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

Question 28

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

Answer 28

As DUANE SYNDROME until proven otherwise!!

Question 29

TX of Duanes

Answer 29

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

Question 30

What type of prism for left type I duanes

Answer 30

Left BO, right BI | Yoked prism

Question 31

Other names ofr Browns syndrome

Answer 31

SO tendon sheath syndrome

Question 32

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

Answer 32

Brown’s syndrome

Question 33

Characteristics of Browns

Answer 33

- majority unilateral - OD>OS - females>males - usually constant but can have intermittent episodes

Question 34

Etiology of Browns

Answer 34

- 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

Question 35

Browns: congenital or acquired?

Answer 35

Congenital | -CAN be acquired

Question 36

How can BRowns he acquired

Answer 36

Trauma, inflammatory disease processes, iatrogenic (surgery) Usually due to injury or inflammation in the region of the trochlea May improve over time

Question 37

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

Answer 37

Browns

Question 38

Forced duction on Browns

Answer 38

Positive

Question 39

Deviation in primary gaze on Browns

Answer 39

Minimal or none

Question 40

What kind of pattern in Browns

Answer 40

May have V pattern eso deviation in up gaze

Question 41

Audible click in Browns

Answer 41

May hear an audible click in elevation

Question 42

Compensatory head posture in Browns

Answer 42

Chin elevation and pointing toward opposite shoulder | -mild downshoot of affected eye in adduction

Question 43

Overaction of the ipsilateral SO in Browns

Answer 43

Absent

Question 44

Palpebral fissure in Browns

Answer 44

Widening

Question 45

Elevation in abduction for the affected eye in BRwons

Answer 45

Normal

Question 46

Where is the restricted elevation in browns

Answer 46

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

Question 47

Binocularity in browns

Answer 47

- 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

Question 48

Differential diagnosis of Brown

Answer 48

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

Question 49

TX of brown

Answer 49

- 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

Question 50

Overall problem with Duanes syndrome

Answer 50

Mechanical restriction, anatomy issue, or innervation issue to LR

Question 51

Overall problem of Browns

Answer 51

SO tendon is thick

Question 52

Etiology of Duanes

Answer 52

Unable to adduct, abduct, or both

Question 53

Etiology of Browns

Answer 53

cant elevate in adduction

Question 54

Onset of Duanes

Answer 54

Congenital

Question 55

Onset of browns

Answer 55

Congenital or acquired

Question 56

Unilateral or bilateral: Duanes

Answer 56

Unilateral

Question 57

Unilateral or bilateral: Browns?

Answer 57

Unilateral

Question 58

Is there amblyopia in duanes

Answer 58

No

Question 59

Is there amblyopia in Browns

Answer 59

No

Question 60

Is there an diplopia in browns

Answer 60

No

Question 61

Is there any diplopia in duanes

Answer 61

No

Question 62

Head posture in duanes

Answer 62

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

Question 63

Head posture in browns

Answer 63

Chin elevation

Question 64

Lid changes in duanes

Answer 64

Narrow palpebral fissure

Question 65

Lid changes in browns

Answer 65

Widening of palpebral fissure

Question 66

Other characteristics of duanes

Answer 66

Globe retraction | Up/downshoot with adduction

Question 67

Other characteristics of browns

Answer 67

V pattern in upgaze