While many studies report improvements with coloured lenses , the effect size is generally small and /or similar to the improvement found with a placebo condition .
Consistent with previous review s and advice from several professional bodies , we conclude that the use of coloured lenses or overlays to ameliorate reading difficulties can not be endorsed and that any benefits reported by individuals in clinical setting s are likely to be the result of placebo , practice or Hawthorne effects
PURPOSE There are many anecdotal cl aims and research reports that coloured lenses and overlays improve  reading performance .
Here we present the results of a systematic review of this literature and examine the quality of the evidence .
Rate of Reading Test: its reliability, and its validity in the assessment of the effects of coloured overlays.
A simple reading test that can be undertaken by disabled readers is described . The test is suitable for use in the optometric clinic , taking less than 2 minutes to administer per passage . Test-retest scores are acceptably reliable . The test reveals increases in the speed of reading when coloured overlays are used both ( 1 ) in children who have made long-term use of coloured overlays for reading , and ( 2 ) in children who will subsequently do so
While many studies report improvements with coloured lenses , the effect size is generally small and /or similar to the improvement found with a placebo condition .
Consistent with previous review s and advice from several professional bodies , we conclude that the use of coloured lenses or overlays to ameliorate reading difficulties can not be endorsed and that any benefits reported by individuals in clinical setting s are likely to be the result of placebo , practice or Hawthorne effects
PURPOSE There are many anecdotal cl aims and research reports that coloured lenses and overlays improve  reading performance .
Here we present the results of a systematic review of this literature and examine the quality of the evidence .