Infantile esotropia

Question 1

Infantile esotropia onset and angle size

Answer 1

Onset birth - 6 months
Large (> 30 angle)
Stable angle
Initial alternation with crossed fixation- free alternating

Question 2

Infantile esotropia BSV, RX and CNS

Answer 2

Potential for normal BSV limited
No significant refractive error
Normal central nervous system

Question 3

What can it be associated with

Answer 3

Latent or manifest latent nystagmus
Apparent defective abduction
Which may become true if left untreated
Dysfunction of oblique muscles

Question 4

Is infantile esotropia associated with OKN, DVD and alphabet patterns

Answer 4

YES

Question 5

Do patients face turn to affected eye

Answer 5

YES

Question 6

Aetiology

Answer 6

Unknown
Hereditary factors
multi-factorial
? Deficient or delayed development of motor fusion
? may be related to poor sensitivity to targets moving away from the infant

Question 7

Investigation- history and angle of deviation

Answer 7

History – onset before 6 months
In view of instability of eye position at this age accurate age of onset difficult to establish
Exact age may affect prognosis

Angle of Deviation
Large
No significant difference between N & D
Plus lenses make little difference
Associated vertical deviation common

Question 8

Investigation- amblyopia and DVD

Answer 8

Amblyopia
Gross amblyopia unusual
Mild to moderate in 35-41%
Much less if untreated (Calcutt)
More common post op

Associated Vertical Deviations
Superior Oblique underactions & V patterns
High incidence of DVD – presentation later

Question 9

Investigation- nystagmus, OKN

Answer 9

Nystagmus
Manifest Latent Nystagmus (MLN)

Asymmetric Optokinetic Nystagmus (OKN)
Abnormal nasal to temporal response
? evidence of lack of binocularity
? abnormal motion processing (Norcia)
Visual cortex fails to transmit temporally directed motion to nucleus of optic tract Also present in normal infants < 3/12 & other forms of strabismus & relatives
relationship with latent nystagmus (Kommerell)
predictor of DVD (Mein) (see 2nd yr lecture)

Question 10

Investigation- AHP, OMs

Answer 10

Abnormal Head Posture (AHP)
Face turn to fixing eye esp if nystagmus is present
Head tilt to fixing eye but tilt more common with DVD but then more often to non fixing eye

Ocular Movements
Apparent defective abduction if actually present most likely due to Medial Rectus contracture
Test with Doll’s Head and with occlusion
Dysfunction of obliques pos. IO o/a SO u/a (ensure not cong. SO palsy)
Atropic muscle pulleys cause upshoots downshoots

Question 11

Assessment of BSV

Answer 11

Assessment of Binocular Function
Rarely demonstrable pre-op
However difficult to test due to age
Has been shown to occur post-op

Question 12

Aim of management

Answer 12

To achieve equal visual acuity, attain a good alignment and ideally gain some form of binocular co-operation.

Question 13

If angle is greater than 35 dioptres

Answer 13

Surgery

Question 14

If angle is stable and less than 35 dioptres

Answer 14

BT/ surgery

Question 15

If angle is variable and less than 35 dioptres and pt is younger than 8/12

Answer 15

Observe/ BT

Question 16

If angle is variable and greater than 35 dioptres and pt is younger than 8/12

Answer 16

Surgery/ BT

Question 17

If 8 month old has angle less than 40 dioptres management is

Answer 17

observation

Question 18

Is spontaneous recovery possible (<40D and intermittent or variable cases)

Answer 18

Yes, it has been reported in 27% of cases but these were predominantly in those that were referred early; had an angle less than 40∆ which was intermittent or variable on presentation.
(PEDIG 2002)

Question 19

Management options- RX, Amblyopia, Occlusion

Answer 19

Order any significant refractive error
Mostly emmetropic Most would order +2.50 or above

Treat any amblyopia
Fixation pattern helps monitor progress
Limitations of preferential looking
Risk of occlusion amblyopia

Use of alternate occlusion for ‘clean slate’ (Jampolsky 1978)

Question 20

Management options- Surgery

Answer 20

Early v late argument
Evidence more likely to achieve some form of BSV if before 2 yrs of age (European early vs late infantile strabismus surgery survey)
more accurate measurements after 2yrs
More recently suggesting under 6/12 preferable for stereopsis 78% achieved SA as opposed to 61% operated on from 7-12 months (Birch & Stager 2006)
Age of presentation often limiting factor

Question 21

What can early surgery increase the likelihood of

Answer 21

good stereopsis

Question 22

What type of surgery is used - 3

Answer 22

bilateral MR recessions with/ without conj recessions (25-45∆)
Bilateral MR recession and single LR resection (50-65∆)
Combine with BT to both MR if >70∆

Question 23

What is the effectiveness of BT

Answer 23

Results found BT less effective than surgery in esotropias >35∆ but comparable to surgery in those <30∆ Although up to 3 injections could be required
De Alba Campomanes et al 2010

For angles >65∆ success has been shown by combining BT to one or both MR and bilateral MR recessions