EXOTROPIA

GEORGE N PAPANIKOLAOU

SHO OPHTHALMOLOGY

SINGLETON HOSPITAL

SWANSEA

• INTERMITTENT

1. Basic

2. Divergence excess

3. Convergence insufficiency

3. Simulated or Pseudo-Divergence excess

BURIAN’S CLASSIFICATION

Type Description %

Basic D=N 37Tenacious proximal fusion

D>N 60 min occlusion D=N

40

High AC/A ratio D>N 5Proximal convergence D>N+AC/A

normal4

Low AC/A ratio N>D 11Fusional convergence insufficiency

N>D <1

Pseudo-Convergence insufficiency

N>D 60 min occlusion D=N

<1

KUSHNER’S CLASSIFICATION

• CONSTANT CONCOMITANT

1. End-stage decompensated intermittent

2. Infantile (NEUROLOGICAL IMPAIRMENT)

3. Sensory

4. Consecutive

5. DHD

• CONSTANT INCOMITTANT

1. III palsy

2. Duane type II

3. Primary monofixational exo

4. Craniofacial abnormalities/ orbital pathology

5. INO

6. MG

• PSEUDOEXOTROPIA

1. Positive angle kappa without ocular abnormalities

2. Wide IPD

3. Positive angle kappa+ ocular abnormalities

DIAGNOSTIC WORK-UP

• VA

• Motility

• Measurements (N, 6m, distance)

• Refraction

• Pupils/ Slit-lamp/ Fundus (sensory)

• Proptosis

• CT/ MRI

• Tensilon test

CLINICAL CHARACTERISTICS

INTERMITTENT (IDEX)

Age: 6/12- 4y/ F>M/ >10/ uni-, bilateral

1% of population

? Progressive/ stable/ improve

Bright light

A and V patterns/ hypertropias

No amblyopia/ Good stereopsis

No diplopia when exo (suppression+ARC)

Panoramic vision (large angle/ no confusion)

Fatigue/ illness/ day dreaming/ visual distraction-inattention/ distance viewing/ alcohol/ sedatives

HISTORY

1. Family history

2. Age of onset

3. Progression

4. Frequency/ Triggers

5. Control

• Good

• Fair

• Poor

NCS

EVALUATION OF IDEX

1. Convergence

2. PCT (primary:D, N/ lateral gaze (incomitance)

3. N/D disparity: AC/A ratio

4. Far distance measurements

5. D+N after 30-60min monocular occlusion (max)

6. Binocular VA at 6m

7. Min. 3 visits

MANAGEMENT

PROBLEMS:

• Lack of standard definition of success

• Variability of classification systems

• Multiple treatment approaches

• Paucity of long term data

• Undefined natural history of disease

• Absence of randomised evidence

NON-SURGICAL

• <20

• Very young

AC/A ratio

OPTIONS

1. Treat amblyopia/ anisometropia/myopia/ > +4.00D

2. Minus lenses/ Bifocals

3. BI prisms

4. Tinted gls

5. BTX

6. Part time patching (passive orthoptic Rx)

7. Active orthoptic Rx

SURGICAL

• >20• >50% of time• Deterioration of control for near• Failure of non-surgical• Problems at school

1. Early

2. Late (>5y)

BEST RESULTS (sensory) <4 years

Success: 60-70%

GENERAL PRINCIPLES

• Overcorrection (10-15 )

• Operate on the largest distance deviation

• Lateral incomitance >10 : reduce surgical dosage

• >35- 50: 3 muscles

• Adjustable sutures

• Large R+R: induce incomitance

CLASSIC TEACHING

Divergence excess BLR

Basic R+R

Simulated divergence excess R+R

Convergence insufficiency BMR

Type Rx/PROGNOSIS

Basic BLR recession or R and R

Tenacious proximal fusion BLR recession/ GOOD

High AC/A ratio Overcorrecting minus lens spectacles with bifocals/ consecutive eso at near

Proximal convergence BLR recession

Low AC/A ratio Poor response

Fusional convergence insufficiency

Convergence trainining

Pseudo-Convergence insufficiency BLR recession

MANAGEMENT BASED ON KUSHNER’S CLASSIFICATION

Surgical dosages (symmetrical surgery)Surgical dosages (symmetrical surgery)

Angle () Recess LR (mm) Resect MR(mm)

15 4.0 3.0

20 5.0 4.0

25 6.0 5.0

30 7.0 6.0

40 8.0 6.0

Surgical dosages for monocular recess-resect Surgical dosages for monocular recess-resect proceduresprocedures

Angle Recess LR (mm) Resect MR(mm)

15 4.0 3.0

20 5.0 4.0

25 6.0 5.0

30 7.0 6.0

40 8.0 6.0

50 9.0 7.0

60 10.0 8.0

70 10.0 9.0

80 10.0 10.0

1. Some binocularity achieved

2. Psychosocial impact

3. Compromise in occupational and professional life

BENEFITS OF TREATMENT

MANAGEMENT OF CONSECUTIVE ESOTROPIA

• alternate occlusion

• prisms

•BTX (one MR/ if fusion present)

• re-operation after 6/12

MANAGEMENT OF UNDERCORRECTION:

• non- surgical

• surgical (same dosage as if for primary)

MANAGEMENT OF RECURRENT EXOTROPIA (usually within 6/12):

• prisms + minus lenses

• re-operate

Main Results No studies were found that met our selection criteria and therefore none were included for analysis.

Reviewers' conclusions The available literature consists mainly of retrospective case reviews. These are difficult to compare and analyse due to a large variation in the definition of intermittent distance exotropia, intervention criteria and outcome measures. However there seems to be general agreement that non-surgical treatment is most appropriate in small angle deviations or as a supplement to surgery. Studies were found supporting both early and late surgical intervention so the optimal timing of surgical intervention cannot be concluded. Recent work indicates that bilateral surgery may be the most effective surgical procedure in these cases. There is clearly a need for carefully planned clinical trials to be undertaken to improve the evidence base for the management of this condition.

This review should be cited as:Richardson S, Gnanaraj L Interventions for intermittent distance exotropia (Cochrane Review). In: The Cochrane Library, Issue 4, 2003. Chichester, UK: John Wiley & Sons, Ltd.

RCT’S

PLEASE!!!!