Project Details

Improving Control of Alignment in Intermittent Exotropia

Eileen Birch, PhD

Summary

BACKGROUND: Currently, less than 30% of children have good long-term outcomes following treatment for intermittent exotropia (IXT). Although poor binocular sensory status (suppression and stereoacuity) is thought to be the major factor in poor treatment outcomes, there have been no prospective studies or randomized clinical trials of sensory fusion training GAP: The low rate of treatment success for IXT is most likely due to poor sensory status; there is a need for a sensory intervention that can reduce suppression and support stereoacuity. HYPOTHESIS: Sensory training to decrease suppression and engage stereoacuity may improve control of alignment in children with IXT and moderate to poor control alignment. METHODS: Forty-one children (mean age :7.4 years) were randomly assigned to watch dichoptic 3D or 2D movies (3 movies/week) for 4 weeks after referral by a pediatric eye specialist who completed assessments of the triple office control score (graded measure of IXT control) and ocular alignment with distance and near fixation. Eligible children spontaneously manifested constant or intermittent exotropia (distance control score of ≥3, mean 3.6±0.7) at distance. Primary outcome was change in distance control score after treatment assessed by the referring pediatric eye specialist who was blinded to treatment assignment. Secondary outcomes included change in near control score, ocular alignment, and stereoacuity. Study population: Eligible children with IXT, ages 4-10 years, with normal visual acuity, moderate to poor control of ocular alignment, ocular misalignment >10 pd at distance and near, Basic IXT or Pseudo Divergence Excess IXT. RESULTS: After 4 weeks of treatment, 3D-assigned children’s distance control score significantly improved 1.38±1.06 (95%CI: 0.78-1.98); there was no significant improvement for the 2D-assigned children 0.79±1.44 (95%CI: -0.06-1.64). Near control score, ocular alignment, and stereoacuity did not change significantly with either treatment. IMPACT: Sensory training to decrease suppression and engage stereoacuity with 3D movies improved control of eye alignment. Prior work has demonstrated that Improved alignment promotes a positive self-image, important for the child’s social interactions and quality of life.

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