Infantile esotropia Flashcards
Infantile esotropia onset and angle size
Onset birth - 6 months
Large (> 30 angle)
Stable angle
Initial alternation with crossed fixation- free alternating
Infantile esotropia BSV, RX and CNS
Potential for normal BSV limited
No significant refractive error
Normal central nervous system
What can it be associated with
Latent or manifest latent nystagmus
Apparent defective abduction
Which may become true if left untreated
Dysfunction of oblique muscles
Is infantile esotropia associated with OKN, DVD and alphabet patterns
YES
Do patients face turn to affected eye
YES
Aetiology
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
Investigation- history and angle of deviation
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
Investigation- amblyopia and DVD
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
Investigation- nystagmus, OKN
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)
Investigation- AHP, OMs
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
Assessment of BSV
Assessment of Binocular Function
Rarely demonstrable pre-op
However difficult to test due to age
Has been shown to occur post-op
Aim of management
To achieve equal visual acuity, attain a good alignment and ideally gain some form of binocular co-operation.
If angle is greater than 35 dioptres
Surgery
If angle is stable and less than 35 dioptres
BT/ surgery
If angle is variable and less than 35 dioptres and pt is younger than 8/12
Observe/ BT
If angle is variable and greater than 35 dioptres and pt is younger than 8/12
Surgery/ BT
If 8 month old has angle less than 40 dioptres management is
observation
Is spontaneous recovery possible (<40D and intermittent or variable cases)
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)
Management options- RX, Amblyopia, Occlusion
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)
Management options- Surgery
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
What can early surgery increase the likelihood of
good stereopsis
What type of surgery is used - 3
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∆
What is the effectiveness of BT
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
