RESUMEN
PURPOSE: To determine whether a typical vision therapy (VT) programme designed to improve visual information processing (VIP) skills is effective in improving these skills and/or academic performance. METHODS: We used a double-blind, randomised clinical trial to compare VIP VT to placebo training. Participating schools referred a sample of 579 early primary school children identified as being within the lower third of their class for literacy. From the referred sample, we identified 247 children eligible to participate (passed visions and auditory processing screening, and VIP performance <34th percentile), 94 of whom participated. Matching IQ, school grade and sex was achieved by sorting hierarchically on these values and then alternately allocating to VT or placebo groups. Both programmes ran for 10 weeks and consisted of 33 h working at home and 4 h working in office. The VT programme was indicative of that employed in Australian paediatric optometry practices, with the placebo programme containing similar activities, except targeting skills within a child's competencies and with specific VIP development activities removed. The main outcome measures were score change on three standardised educational tests (reading comprehension, spelling and mathematics) and six VIP tests, both immediately post-intervention (PI) and 6 months later. RESULTS: Sixty-nine children completed the programmes. The VT programme produced no significant improvement in the three educational tests or in five of the six VIP tests compared to the control. The VT programme improved visual sequential memory (VSM) by a moderate amount compared to the control (Cohen's d = 0.57 and 0.52, immediately PI and at 6 months, respectively: p < 0.03 and p < 0.02). CONCLUSIONS: The VIP and academic performance benefits from a VT programme were largely identical to those from a control programme, both immediately and 6-month PI. Placebo effects and general effects such as improvements in executive function and/or regression-to-the-mean could be mistaken for specific programme effectiveness.