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Dyslexia: some of the devices sold to make reading easier are not effective

​Devices such as lights and strobe glasses that are supposed to make reading easier for dyslexic people actually have no impact. These are the findings of a study conducted by a team from UNICOG (NeuroSpin) and published in the journal Proceedings Royal Society. ​

Published on 28 January 2024

Dysle​​xia is a neurodevelopmental disorder characterised by significant difficulties in learning to read. It is estimated that between three and twelve per cent of children suffer from dyslexia.​

Treatment for dyslexic children aims to enable them to develop strategies to overcome their difficulties, and is based mainly on speech therapy. Some devices can also be used to adapt the visual presentation of content to help dyslexic people. These include electronic books that enlarge the size of the ​letters, space them out, change the background colour or change the font. However, only the enlargement and spacing of letters have been shown to be effective.​

Very rec​ently, new 'flickering' or stroboscopic devices have appeared on the market, which are also supposed to make reading easier for dyslexic people. They have been developed on the basis of a hypo​​thesis: unlike normal readers, dyslexics do not have a dominant eye and are unable to 'choose' between two superimposed images. High-frequency flashing, imperceptible to the naked eye, turns off one of the two images, making reading easier.

Numerous testimonials tend to confirm the effectiveness of these devices. However, the initial hypothesis​​ has not been substantiated and the supposed virtues of stroboscopic glasses have not yet been verified.​

A team from the UNICOG laboratory (NeuroSpin department) therefore decided to scientifically test this type of device. ​

22 dyslexic children volunteers were recruited for this experiment, which aimed to assess the impact of the L​​​exilight® lamp and Lexilens® glasses on reading fluency, letter identification and mirror letter proce​​​ssing (b and d, p and q). No detectable impact of the stroboscopic devices was observed.

The researc​hers also manipulated, in two participants who claimed to benefit from flashing glasses, wh​​ether the glasses were actually switched on or whether the participant thought they were. Only a small placebo effect was observed in one of the participants.

The results of the study contrast sharply with marketing claims that these tools can help 90% of dyslexics. T​​hey underline the importance of rigorous scientific research to enable people with dyslexia to make informed decisions about the aids that may be sold to them.


Marie Lubin​​eau (

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