It is normal for academics to have a web page where they outline their research interests and provide links to their publications. They can be of great use to other academics. However, this university hosted web-page goes beyond that and is primarily aimed at the general public. Although there is a disclaimer that this is Professor Wilkins' website and the 'University of Essex does not endorse the the content on this site' I think it could still be argued that the reputation of Essex University is being used to market an unproven and probably ineffective product.
Moving on to some of the specific claims of this website.
1) 'A variety of controlled trials have shown that placebo effects are not a sufficient explanation' (for improvements in reading with coloured lenses and overlays).
This claim deserves close scrutiny. I have discussed placebo effects, novelty effects and the Hawthorne effect in some detail in other posts. The best way to minimise the risk of placebo effects contaminating the data is the double masked randomised controlled trial where neither the participants nor the experimenters know which is the experimental and which is the control or placebo intervention. There are no doubled masked RCTs at low risk of bias that show a beneficial effect of coloured filters on reading. The one doubled masked RCT of precision tinted lenses in children with visual stress and dyslexia published in 1994 was hampered by a high rate of drop out but showed no improvement in reading speed accuracy or comprehension compared to the placebo control group see my review of this study in my post of February 22nd 2015.
Another frequently cited study was published in 2002 and was reviewed in my post of March 2015
It reports a study comparing reading of non-connected text, using a chosen overlay with a pale yellow filter that was manifestly different to the chosen overlay; the study was clearly unmasked. The placebo effect of the control intervention was said to be enhanced by labelling the filter 'Research Model A16 Anti UV/IR Filter. Made in the USA' and describing it as a wonderful new discovery from the United states. The underlying assumption is that the placebo effect of the experimental intervention is known and that the placebo effect of the control intervention can be precisely modulated to match it. This assumption is unfounded. Indeed, the most powerful driver of the placebo effect is the relationship between the participant and the experimenter. The richer therapeutic ritual and enhanced relationship with the experimenter associated with selecting an overlay was likely to have been a powerful driver of the placebo effect.
There is a striking gradient between well-controlled studies that show no treatment effect, poorly masked studies that compare chosen overlay or with clear or no overlay which show small effects and testimonials that report huge or life changing effects.
The claim that placebo effects are not a sufficient explanation for the increased rate of reading with overlays is unfounded. Indeed, placebo effects are the most probable explanation for the increase in reading rate sometimes observed with coloured lenses and overlays in poorly controlled studies.
2) 'Unlike some other recent systems of overlays, the "Intuitive Overlays" offer a large range of colours and have been shown to increase reading speed' - a link is provided to a paper that reports a 'head to head' trial of Intuitive overlays and Reading Rulers from the Crossbow Education. This study is at high risk of bias according to the Cochrane tools for assessing bias. Visual stress was diagnosed by asking leading questions about visual stress symptoms to children in groups of 15. Children with high symptom scores then selected their optimum colour form Intuitive overlays and Crossbow Reading Rulers. The study was not masked. Even so, the results are not very impressive. There was no difference in symptom scores between the two types of overlays. There was a small difference in reading speeds. No overlay 75.7 wpm (SD 26.9) Intuitive overlay 80.5 wpm (SD 27) and Eye Level Ruler 74.7 wpm (SD 25.8).
In short, an unmasked study in which one of the authors has a financial interest in Intuitive overlays found a small difference in reading using a non-standardised test of unknown relevance to real world reading.
3) 'The use of colour to treat visual discomfort and perceptual distortions (visual stress) has been the subject of recent controversy' Professor Wilkins acknowledges that the treatment of visual stress with colour is controversial and provides a link to his answers to those sceptics which will be the subject of a future post.
Conclusion
I am not sure why the University of Essex provides what I think is an advertising platform for the use of coloured overlays and lenses. Indeed, this is the kind of advertising money can't buy. If I had developed a product that I wished to sell I do not think my current employer would allow me to use their website and their reputation for promotional purposes.
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