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Binocular vision YR 3 > Duane's retraction syndrome > Flashcards

Duane's retraction syndrome Flashcards

1
Q

what is the forced duction test?

In surgery they see if ther

A

In surgery they see if there is any limited movments with the eyes

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2
Q

What is globe retracted?

A

The eye is moved back into the orbit

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3
Q

what is up shoots and down shoots?

A

Shoot vs dirft: shoot is quicker and moves when looking in a particular direction

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4
Q

What are the characteristics of mechanical anomalies?

A

Equal limitations on duction and version
limitaion in opposite postions ; like abductiona nd aduction
muscle sequelue ; they only have the second step which is over action of the contralateral synergist

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5
Q

describe what duane’s retraction syndrome is

A

Limitation of horizontal eye movements with retraction of the globe on adduction

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6
Q

list 7 features of duane’s

A
  • Limitation of horizontal eye movements
  • Abnormal head posture: depending on the underlying deviation they have in pp
    Eso deviation face turn to affected side
    Exo deviation with limited adduction face turn to unaffected side
  • Manifest deviation (may or may not have)
  • Retraction of globe on adduction with narrowing of palpebral fissures
  • Widening of palpebral fissures on abduction
  • Up/down shoots on adduction
  • Poor convergence (except in one type of duane’s)
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7
Q

what is the AHP for a eso deviation in duane’s

A

face turn to affected side

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8
Q

what is the AHP for a exo deviation in duane’s

A

face turn to unaffected side

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9
Q

list 6 ocular associations of duane’s syndrome

A
  • coloboma
  • heterochromia irides
  • microphthalmos
  • cataract
  • crocodile tears
  • persistent pupillary membrane
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10
Q

explain what the central defect aetiology of duane’s syndrome is

A

Defective Innervation
Omission, substitution or duplication of nerve supply of the LR muscle

Co-contraction theory
LR muscle partially innervated by III nerve, with or without VI innervation
MR and LR muscle fire simultaneously leading to limitation of horizontal movement and globe retraction seen on adduction

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11
Q

explain what the peripheral defect of duane’s syndrome is

A

Mechanical
Abnormal extraocular muscles or their tendons
Posterior insertion of MR (acts as a retractor)

Inelastic fibrous LR or fibrous bands
Hypoplasia of LR
Prevent LR from relaxing or contracting

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12
Q

what is the 2 ways of classifying duane’s syndrome

A
  • Brown (1950) clinical picture of OM
    Type A, B, C
  • Huber’s (1974) based on EMG findings and co-contraction theory where LR receives co-innervation from III and VI nerves
    Many patients do not fit neatly into Type I, II and III
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13
Q

which classification is done by looking at ocular motility picture that we see in clinic

A

Brown (1950) clinical picture of OM

Type A, B, C

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14
Q

what is an easy way to remember the Huber’s classification of duane’s syndrome

A

Type 1 (has 1 letter D) characterised by abduction deficit

Type 2 (has 2 letter D) characterised by adduction deficit

Type 3 (has 3 letter D) characterised by adduction and abduction deficit

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15
Q

which type of duane’s syndrome classification is generally used in a hospital based practice

A

Brown (1950) clinical picture of OM

Type A, B, C

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16
Q

briefly describe Type: A, B and C classification of duane’s syndrome

A
  • Type A limited abduction > adduction
    limited adduction and abduction, but abduction is greater affected than adduction
  • Type B limited abduction, but normal adduction
    convergence will be fine because adduction is normal
  • Type C limited adduction > abduction thus exotropia in pp
    limited abduction and adduction, but adduction is greater affected than abduction
17
Q 
describe the clinical signs of type A of the Brown (1950) classification of duane's syndrome of: 
Globe retraction 
limited ABD
AHP
Cover test without AHP
PCT angle 
Reduced convergence 
BSV
A

Globe retraction: Yes

limited ABD: abd > adduction

AHP: Face turn affected side, Dist > near

Cover test without AHP: E / ET for near, ET for distance

PCT angle: D>N

Reduced convergence: Defective

BSV: Yes

18
Q 
describe the clinical signs of type B of the Brown (1950) classification of duane's syndrome of: 
Globe retraction 
limited ABD
AHP
Cover test without AHP
PCT angle 
Reduced convergence 
BSV
A

Globe retraction: Yes

limited ABD: Abduction only, (adduction normal)

AHP: Face turn affected side, Dist > near

Cover test without AHP: E / ET for near, ET for distance

PCT angle: D>N

Reduced convergence: Normal

BSV: Yes

Convergence is normal, px is still likely to have an ESOT in pp

19
Q 
describe the clinical signs of type C of the Brown (1950) classification of duane's syndrome of: 
Globe retraction 
limited ABD
AHP
Cover test without AHP
PCT angle 
Reduced convergence 
BSV
A

Globe retraction: Yes

limited ABD: Add > abduction

AHP: Face turn unaffected side, Near > list

Cover test without AHP: XT for near, XT/ X for distance

PCT angle: N>D

Reduced convergence: Defective / absent

BSV: Yes

Convergence will be reduced as adduction is greater than abduction, px will have EXOT in pp

20
Q

what will be seen in a patient in type A duane’s retraction syndrome in the left eye:
when they look to the left
primary position
when they look to the right

A

when they look to the left: L eye doesn’t abduct as well, but R eye is fine i.e. adducts fully

primary position: slight left esotropia

when they look to the right: adduction of L eye is also limited but to a lesser amount than the abduction deficit

21
Q

what will be seen in a patient in type B duane’s retraction syndrome in the right eye:
when they look to the left
primary position
when they look to the right

A

when they look to the left: adduction of R eye is normal

primary position: slight right esotropia

when they look to the right: limited abduction of right eye

22
Q

what will be seen in a patient in type C duane’s retraction syndrome in the right eye:
when they look to the left
primary position
when they look to the right

A

when they look to the left: level of limitation of adduction is greater compared to abduction of that eye

primary position: right exotropia

when they look to the right: R eye slight limited abduction

23
Q

list 9 things that should be in the orthoptic report of someone with a suspect duane’s syndrome

A 
- Case history 
Abnormal eye movements
Eye looks sunken / ptosis
One eye slow to follow
AHP (likely reason for presentation to eye clinic)
  • Birth history
    Any pregnancy problems or medication
  • General health
  • Family history
    As theres some genetic link, so must enquire
  • Abnormal head posture
    Centralise narrow field of BSV
  • Cover test – with and without AHP
  • OM - carefully document
  • Changes of lid and globe position
  • Confirmation of BSV with AHP
24
Q

when a px with duane’s syndrome has a EXOT or ESOT in pp, what will they not experience and what will they experience instead

A

will not experience diplopia, will suppress instead

25
Q

explain why you will carry out a cover test with the AHP and without the AHP in duane’s syndrome

A
  • with the AHP: to confirm that they do have a latent deviation that they can control to
  • without AHP: to determine if esotropia or exotropia and this will help classify the type of diagnosis that they have
26
Q

list the 7 things you will do in your management for someone with duane’s syndrome

A
  • Correct any refractive error
  • Fundus and media check
    for no other pathology causing the reduced vision
  • Amblyopia treatment if necessary
    as px can maintain AHP and avoid amblyopia
  • Differential diagnosis
    • Moebius syndrome (VI and VII CN)
    • Sixth nerve palsy
  • Generally conservative treatment as:
    • Symptom free
    • Slight abnormal head posture
    • Well compensated deviation
    • Comfortable binocular single vision (BSV)
  • Manage patient/parent expectations:
    • Cannot restore normal eye movements
    • Patient will still be able to drive
  • Indications for further treatment
    - Prisms for compensation
    - Moderate AHP
    - Poor cosmesis (large esotropia)
27
Q

name the 2 differential diagnosis of duane’s retraction syndrome

A
  • Moebius syndrome (VI and VII CN)

- Sixth nerve palsy

28
Q

how can you tell that a patient has duane’s retraction syndrome and not Moebius syndrome instead

A

because patients with Moebius syndrome will have 6th and 7th CN involvement too
and type B duane’s syndrome, where their abduction is only affected and adduction is normal would look as if these patients have got a 6th nerve palsy, but with Moebius syndrome they will have 7th nerve involvement too

29
Q

how can you tell that a patient has duane’s retraction syndrome and not a sixth nerve palsy instead

A

because there will be no lid/globe retraction

and the esotropia will be greater in distance fixation compared to near fixation with 6th nerve palsy

30
Q

give 4 reasons why treatment for duane’s syndrome is generally conservative

A
  • Symptom free
  • Slight abnormal head posture
  • Well compensated deviation (in presence of AHP)
  • Comfortable binocular single vision (BSV)
31
Q

what 2 things will you explain to the patient/parent about their expectations

A
  • Cannot restore normal eye movements
    so if they do require any treatment, the limitations of the eye movements they have will remain exactly the same post operatively. so any surgical treatment is only for the underlying ESOT or EXOT that they have in pp, and not to improve their horizontal eye movements
  • Patient will still be able to drive
    as px can see BSV in pp
32
Q

list the 3 things that will give indications for further treatment for duane’s syndrome
why for each one and what can be done

A
  • Prisms for compensation
    if px decompensated later in life or becomes more symptomatic and complains of diplopia
    can use a fresnel prism on their glasses
  • Moderate AHP
    for a large squint in pp and is difficult to maintain BSV wth the AHP, then do surgery to reduce the primary deviation they have, so they can control that to a small AHP, especially if theres poor cosmesis of the underlying deviation
  • Poor cosmesis (large esotropia)
33
Q

what are the 3 aims for treating/managing someone with duane’s syndrome

A
  • Improve field of BSV
  • Reduce AHP
  • Improve cosmesis if no BSV
34
Q

what is the surgical management for the esotropia in someone with duane’s syndrome and what this depends on
and which 2 types this applies to

A

Recess (weaken) one or both MR depending on angle or vertical tendon transfer

Type A and B

35
Q

what is the surgical management for the exotropia in someone with duane’s syndrome
and which type this applies to

A

Unilateral or bilateral LR recessions

Type C

36
Q

what is the surgical management for the globe retraction, up and down shoots in someone with duane’s syndrome and why

A

Ipsilateral MR and LR recessions to reduce effect of co-contracture

37
Q

what is the aim of the surgery in duane’s syndrome

A

it is just to improve the angle of the deviation and not to improve movements/limitations

38
Q

What are the characteristics of mechanical anomalies?

A

Equal limitations on duction and version
limitaion in opposite postions ; like abductiona nd aduction
muscle sequelue ; they only have the second step which is over action of the contralateral synergist

Binocular vision YR 3 (20 decks)

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