Children with low literacy and poor stereoacuity: an evaluation of complex interventions in a community-based randomized trial.

Purpose: To assess, among children with low literacy and poor stereoacuity, the efficacy of two intervention programs on child vision and education compared to a control program.

Methods: Eighty-eight children aged 8 to 13 years who had reading problems, and demonstrated poor stereoacuity as measured by the Titmus stereocircle test (> 100 seconds arc) or computerized assessment were randomized to one of two intervention programs: Lawson vision or Phono-Graphix, or a control group: Parental Literacy Support. Vision (Lang test, visual acuity, convergence insufficiency symptom survey) and education assessments (Woodcock Reading Mastery Tests-Revised) were conducted at baseline, intervention end (10 weeks), and 36 weeks. Analysis used intention to treat multi-level models.

Results: Compared to the parental literacy support group, convergence insufficiency symptoms were reduced 36 weeks post-randomization amongst those receiving the Lawson orthoptic intervention (mean difference -5.55; 95% confidence interval (CI): -11.1 to -0.05, P < 0.05). Stereoacuity, measured by the Lang test, improved for both the Lawson and Phono-Graphix interventions compared to the parental literacy support group (-1.01; 95% CI: -1.6 to -0.4, P = 0.001, and -0.77; 95% CI: -1.4 to -0.2, P = 0.01). At the 36 week follow-up assessment, word identification had also improved for the Lawson and Phono-Graphix groups but other educational outcomes did not improve.

Conclusion: A formal randomized control trial was feasible in this setting. Intervention among children with poor stereoacuity and low literacy produced small improvements in stereopsis and convergence insufficiency symptom scores. Further randomized control trials should be conducted to clarify the role of orthoptic intervention on literacy in selected child populations.