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Assessing divergence in children with intermittent exotropia
Laura Liebermann1, Sarah R Hatt, David A Leske
1Department of Ophthalmology, Mayo Clinic, Rochester, Minnsesota 55905, USA.
Strabismus
|March 7, 2012
Summary
Nearly half of children with intermittent exotropia have reduced distance fusional divergence, while near fusional divergence is typically normal. This finding may help assess fusion fragility in these patients.
Area of Science:
- Ophthalmology
- Pediatric Ophthalmology
- Strabismus Research
Background:
- Intermittent exotropia (XT) is a common form of strabismus in children.
- Understanding fusional divergence is crucial for managing XT and maintaining binocular vision.
Purpose of the Study:
- To quantify fusional divergence capabilities in children diagnosed with intermittent exotropia.
- To compare fusional divergence in children with intermittent XT to that of visually normal children.
Main Methods:
- Retrospective analysis of 32 children with intermittent XT (ages 4-13) and 38 controls.
- Fusional divergence break points measured using prism bar; subnormal defined as <5th percentile in controls.
- Correlations assessed between divergence, convergence, control score, and angle of deviation.
Main Results:
- Fusional divergence distribution was normal at near but bimodal at distance in intermittent XT.
- Subnormal divergence observed in 9% at near and 48% at distance.
- Moderate correlation found between near divergence and convergence break points (r=0.44, P=.01).
Conclusions:
- Children with intermittent XT often exhibit normal near fusional divergence but reduced distance fusional divergence.
- Near divergence break point magnitude correlates with near convergence break point magnitude.
- Measuring fusional divergence may offer insights into the stability of fusion in intermittent XT.
