Condition category
Not Applicable
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Up to half of all children with reading problems find it difficult to see text clearly. Letters appear to blur, glare, go double or move around, and these problems can give them headaches. Previous research has shown that these problems may be due to the poor readers having reduced sensitivity to time varying low−level visual stimuli, for example, moving dots. This sensitivity is important for making visual targets appear stationary despite eye movements and it is controlled by a system of large specialised (magnocellular) neurones in the brain. The development of these neurones have been found to be impaired in many children with reading problems. There are good physiological reasons for supposing that viewing text through either simple blue or yellow coloured filters may improve magnocellular function. We have found that indeed this is so, and that the use of these filters is often followed by rapid reading and spelling progress. However, these claims have been disputed. There is no agreement about whether coloured filters can really help more than a placebo. Here, we will test if simple and cheap blue or yellow filters can really help children with reading difficulties. If so, this low cost technique should be used wherever appropriate, in order to help the 10−20% of primary school children who have great difficulties learning to read.

Who can participate?
Children experiencing reading difficulties

What does the study involve?
The carers of all potential participants attending Dyslexia Research Trust (DRT) clinics are asked to allow their child to take part in the research. The only difference from the routine assessments carried out in the clinics is that each child is treated with blue, grey and then yellow filters in a random order. Upon arrival at the DRT, we discuss the study with them, ensure that both the child and carer understand why we are doing the study, what we hope to find, what will be expected of them and ask them to sign a consent form. Psychometric assessments (pen and paper tests) are carried out along with a visual assessment, clinical tests of vision and recordings of the movement of eyes. Following completion of these tests each child is given an envelope containing either yellow, grey or blue filters. This envelope is not to be opened until they leave the clinic to ensure that the researchers do not know which colour the child received. At a second appointment after 3 months, the filters will be swapped to another colour. The researchers will be blind to the colour the child receives at any of the follow ups. To assess the effects of the yellow, grey and blue lenses the children are further assessed at 3, 6 and 9 months when all the psychometric and visual assessments are retested. We ask the participants not to disclose the colour of the filter they have received to the researchers . Only at the end of the fourth and final assessment are researchers told treatment order, once the participant has finished the study.

What are the possible benefits and risks of participating?
None of the colours are likely to harm the children in any way and the reading of the majority of them is likely to be helped by one or another colour.

Where is the study run from?
The Dyslexia Research Trust clinic (Reading)

When is the study starting and how long is it expected to run for?
October 2014 to October 2019

Who is funding the study?
Dyslexia Research Trust (UK)

Who is the main contact?
Professor John Stein

Trial website

Contact information



Primary contact

Prof John Stein


Contact details

Sherrington bdg.
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

The effect of wearing yellow or blue filters on reading and spelling ability: a randomised controlled trial


REading With Blue or Yellow Filters (REWBYF)

Study hypothesis

Can wearing yellow or blue filters help some children to learn to read

Ethics approval

University of Oxford Medical Sciences Inter Divisional Research Ethics Committee, 29/10/2014, ref: MSD-IDREC-C2-2014-024

Study design

Randomised controlled trial of yellow, blue or placebo filters in up to 200 7-11 yr old children to determine whether the coloured filter appropriate for their visual reading symptoms can help them to learn to read.

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Please contact Professor Stein for patient information sheets


Backward reading (dyslexia)


Viewing text through yellow, blue or placebo grey filters

Intervention type



Drug names

Primary outcome measures

Reading and spelling changes

To be assessed at 3, 6 and 9 months

Secondary outcome measures

1. BAS matrices
2. Recall of digits
3. Similarities changes
4. Visual symptom changes
5. Random dot motion sensitivity changes

To be assessed at 3, 6 and 9 months

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

Children experiencing reading difficulties

Participant type

Healthy volunteer

Age group




Target number of participants


Participant exclusion criteria

1. Not fluent in English
2. Any diagnosed medical condition

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Dyslexia Research Trust clinic
179a Oxford Road
United Kingdom

Sponsor information


U. Oxford

Sponsor details

Wellington Sq
United Kingdom

Sponsor type




Funder type

Not defined

Funder name

Dyslexia Research Trust (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Publication in neuroscience and educational journals and on DRT website

Intention to publish date

Participant level data

Available on request

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes