The effect of coloured overlays and lenses on reading: a systematic review of the literature
Griffiths PG, Taylor RH, Henderson LM, Barrett BT · 2016
grade Breviewindependentnot-applicable
Sample
51 published items containing 54 data sets, across four colour systems (Intuitive, Irlen, Harris/Chromagen, other)
Population
Children and adults with visual stress, reading difficulty, or both
Design
Systematic review with each data set classified using the Cochrane Risk of Bias tool, and results reported separately by commercial system so that a failure cannot be attributed to using the wrong brand. The key analysis is the relation between risk of bias and reported benefit.
Key findings
Results did not differ by system type or by whether the sample was classified as having visual stress, reading difficulty or both. The MAJORITY of studies carry high or uncertain risk of bias, and the studies at LOWER risk of bias provide LESS support for benefit. Where improvements are reported the effect is generally small and similar to the improvement found with a placebo condition. The authors conclude coloured lenses and overlays cannot be endorsed and that clinical benefits are likely placebo, practice or Hawthorne effects.
Genetic confound
Low; the relevant confound is placebo and expectancy rather than heredity.
DOI / URL
Effects
| Outcome | Metric | Value | Measure | Timing | Vs | Horizon | Class |
|---|---|---|---|---|---|---|---|
| Reading performance with coloured overlays or lenses | effect size vs placebo | small and similar to placebo; less support in lower-risk-of-bias studies | standardized | post-intervention | active-alternative | end-of-treatment | domain-skill |
Cited by
- Brain Gym, Whole Brain Teaching, and the smaller classroom brain fadsdebunkedconf: mediumgc: low