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 .
Effects of wearing yellow spectacles on visual skills, reading speed, and visual symptoms in children with reading difficulties
Background Possible beneficial effects of yellow-tinted spectacle lenses on binocular vision , accommodation , oculomotor scanning , reading speed and visual symptoms were assessed in children with reading difficulties . Methods A longitudinal prospect i ve study was performed in 82 non-dyslexic children with reading difficulties in grade s 3–6 ( aged 9–11 years ) from 11 elementary schools in Madrid ( Spain ) . The children were r and omly assigned to two groups : a treatment ( n = 46 ) and a without-treatment group ( n = 36 ) . Children in the treatment group wore yellow spectacle lenses with best correction if necessary over 3 months ( in school and at home ) . The tests were first undertaken without the yellow filter . With best spectacle correction in each subject , measurements were made of : distance and near horizontal heterophoria , distance and near horizontal fusional vergence ranges , the accommodative convergence/accommodation ( AC/A ) ratio , near point of convergence ( NPC ) , stereoacuity , negative relative accommodation ( NRA ) and positive relative accommodation ( PRA ) , monocular accommodative amplitude ( MAA ) , binocular accommodative facility ( BAF ) , oculomotor scanning , and reading speed ( words per minute ) . The Convergence Insufficiency Symptom Survey ( CISS ) question naire was completed by all children . After the 3-month period , measurements were repeated with the yellow lenses ( treatment group ) or without the yellow lenses ( without-treatment group ) but with refractive correction if needed . Results Over the 3 months , the two groups showed similar mean changes in the variables used to assess binocular vision , accommodation , oculomotor scanning , and reading speed . However , mean relative changes in convergence insufficiency symptoms differed significantly between the groups ( p = 0.01 ) . Conclusion No effects of wearing yellow spectacles emerged on binocular vision , accommodation , oculomotor scanning , and reading speed in children with reading difficulties . The yellow filter had no effect even in children with low MAA and BAF . The reduction in visual symptoms observed in children with reading difficulties using the yellow filters was clinical ly insignificant
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 .