Academic Arguments and Anecdotal Evidence

I don’t normally get involved in the fallout from academic arguments, but on this occasion I will, because, like Mark (, I feel that this needs a response.

You can look through both ends of a portable telescope – it will either magnify what you are looking at, or make it practically disappear. It’s the same with figures. Depending on what position  you want to justify, you choose your data accordingly. So for example global warming is happening, or it isn’t. Drinking a certain amount of red wine is good for you, or it isn’t. Coloured overlays and reading rulers can make a difference to some people’s reading experience, or not. There is actually a wealth of accumulated evidence from 20 years top level academic research to say that they do, plenty of which is peer reviewed – if anybody who wants to look at it, just click on the link in the footnote below. The question is, what do you want to believe?

As one of the people responsible for the significant increase in awareness of Visual Stress over the last decade, the following (alongside the compelling scientific evidence from Essex University, Oxford University and elsewhere) is what I believe. It comes from a seven-year old girl called Maddy, and was given to me by her dyslexia tutor who is a senior professional at a highly respected teaching college:

“ …. The words look different, they won’t stay still and then I start to see ‘rivers in the text’ when I try to  concentrate on text books at my school.  Sometimes it looks like the words are almost 3D and with little lights behind them.  I try blinking a lot to get the words back into focus and then sometimes I even see colours round the text.  But then when I started to use the blue reading ruler, the “weirdness” went away …”

Ah, but there’s a problem, isn’t there? This is merely anecdotal. Maddy doesn’t exist in the cloud of figures that swirl around research like midge swarms. But she has a face, and a story; and I’m sure we could arrange for the people who said “manipulation of the visual system using colour to facilitate reading lacks scientific support” to meet her, or her tutor, if they wished. Or maybe  the American Academy for Pediatrics, Council for Children with Disabilities, American Academy of Ophthalmology, American Association for Pediatric Ophthalmology and Strabismus and the American Association of Certified Orthoptists, who concluded that “… scientific evidence does not support the efficacy of … special tinted filters or lenses in improving long term educational performance” would like to meet the little boy that Mark quoted who, when he looked at text through a blue overlay, said “Is that what you mean by a word? Can I start learning to read now?”

We designed the Eye Level Reading Ruler ten years ago now. There are thousands more stories like Maddy’s out there, of lives that have been changed during that time because “the weirdness went away”.  We hear some of them, when people have the time to write to us, but mostly they exist in the results from schools who assess all their weak readers for visual stress and see significant increases in reading levels when the overlays have been given out; or in the research project from a London University dept of psychology (over 30% increase in reading speed in some children) that wasn’t accepted for peer review because apparently 72 subjects was not enough. To you 72, even though you apparently don’t exist, you know better, and I salute you!

One of our staff sent me an amusing post a few months ago. It went something like this: “To the optimist and the pessimist: While you two were busy arguing over the glass of water, I drank it!Signed, the Opportunist”. Whatever the arguments, there is only one truth. No doubt the midges will continue to swarm. And while they do, the “weirdness” will carry on going away as more people discover how filtering out specific wavelengths of light can neutralise the pattern glare from the repeated stripes in text and put an end to the over-excitation of their visual cortex. So to everyone in that great body of anecdotal evidence, I have one thing to say: we will be here for you.

Bob Hext

Managing Director, Crossbow Education Ltd.

(Unashamed purveyors of Visual Stress Solutions.)


Footnote: Crossbow, Cerium, and I.O.O., who are the leading UK manufacturers of overlays systems, work closely with the scientific establishment to ensure that their products meet the criteria established by the research that detractors say doesn’t exist, but which can be easily found, for example, at , or read about in Arnold Wilkins’s excellent book “Reading Through Colour”. We don’t get involved with coloured lenses: we leave that to the optometrists, whose patients will have their own set of stories of life-changing freedom from Visual Stress. The instrument they use to prescribe the correct lens tint is called the Intuitive Colorimiter. It was developed at Cambridge University and funded by the Medical Research Council. Unscientific? Really?


2 thoughts on “Academic Arguments and Anecdotal Evidence

  1. This is a great and stimulating blog that I have just discovered.
    Testimonials are important but they are only a starting point for research
    A list of references on a personal website is not a substitute for a proper systematic review. Looking more closely at Arnold Wilkin’s website most of the studies are not randomized controlled trials and those that are not support the use of colour to ameliorate visual stress in dyslexia. Furthermore, it is almost entirely comprised of his own studies. As a result it gives a misleading and partial account of the evidence base. That said, it is great the papers are available to download rather than being hidden behind a pay-wall. The ability to download those papers and critically appraise the contents was an important part of my reaching the opposite conclusion.
    Systematic reviews which look all studies, not just those that suit your argument, and select according to predefined methodological criteria that minimise the risk of bias, are a better guide. Two such reviews which meet the widely accepted PRISMA standard have been published and both conclude that the evidence as a whole does not support the use of coloured overlays and lenses to treat that subset with both visual stress and dyslexia(1)(2).
    You state that research from Oxford University (I presume John Stein’s group) and Essex University support the use of coloured overlays and lens. However, their beliefs are mutually contradictory. One believes you have to exactly the right colour determined with the intuitive colorimeter(3) and the other that off the shelf blue or yellow is just as effective (or ineffective in my opinion)(4).
    Medical Research Council patent for the intuitive colorimeter merely states that it is a device for selecting a given colour and makes no mention of it’s use as a therapeutic device. At that time Arnold Wilkins was working in an MRC funded unit which means they maintain intellectual property rights to any technology developed. I believed the Unit lost its MRC funding a long time ago. The MRC certainly does not endorse this type of treatment.
    I don’t mind if people are honest and say they support this treatment on the basis of testimonials – I am happy to respectfully differ from that viewpoint. However, the claim that this is an evidence based treatment is not supported by published evidence.

    1. Albon E, Adi Y, Hyde C, West Midlands Health Technology Assessment Collaboration. The effectiveness and cost-effectiveness of coloured filters for reading disability: a systematic review. Studley: West Midlands Health Technology Assessment Collaboration, Dept. of Public Health and Epidemiology, University of Birmingham; 2008.
    2. Galuschka K, Ise E, Krick K, Schulte-Körne G. Effectiveness of Treatment Approaches for Children and Adolescents with Reading Disabilities: A Meta-Analysis of Randomized Controlled Trials. Lidzba K, editor. PLoS ONE. 2014 Feb 26;9(2):e89900.
    3. Wilkins AJ, Evans BJ, Brown JA, Busby AE, Wingfield AE, Jeanes RJ, et al. Double-masked placebo-controlled trial of precision spectral filters in children who use coloured overlays. Ophthalmic Physiol Opt J Br Coll Ophthalmic Opt Optom. 1994 Oct;14(4):365–70.
    4. Hall R, Ray N, Harries P, Stein J. A comparison of two-coloured filter systems for treating visual reading difficulties. Disabil Rehabil. 2013 Apr 29;

    • I find your response a little difficult to digest, as it seems to insinuate that Professor Wilkins’ integrity is in question. Anyway, I think that overall you are questioning the existence of visual stress based on the studies you have seen. But visual stress is the what, not the why; the why is something you should debate with the likes of Arnold Wilkins, John Stein and Bruce Evans, rather than posting responses to the blogs of non-academics.

      Whether you agree with the conclusions of the existing research base or not (there is a review of the available literature here:, there are hundreds, if not thousands of people who benefit from reading through (or on) colour. We have observed it time and time again. I am one of those people.

      If you were to conduct your own research using the criteria you outlined, I would be very interested to see the results.

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