The MRC connection?

The MRC patent for the Intuitive Colorimeter - 'an apparatus for obtaining a desired tint' - no mention of its therapeutic use

The Medical Research Council (MRC) is the UK's most prestigious grant awarding body in the medical sciences. Grants awarded by the MRC are some of the most difficult to get and are considered a mark of quality. To put it simply, the MRC 'brand' is highly respected and if misused could be a powerful marketing tool. For that reason, the MRC does not allow its name to be used in that way.

The  MRC is liberally name-dropped by proponents of the Intuitive Colorimeter, Intuitive Overlays and Precision Tinted Lenses. You don't have to read very far to find the name of MRC being slipped into the text. In my opinion, this is to lend some sort of respectability to a 'thin' and unconvincing evidence base.

Some examples

The paper 'A Systematic Review of Controlled Trials on Visual Stress using Intuitive Overlays and the Intuitive Colorimeter' that appeared in the December 2016 issue of the Journal of Optometry (in my opinion it is not a systematic review but more on that in a future post). The authors name-drop the MRC. For example, in paragraph two of the introduction, it is stated that 'for these reasons, this paper reviews evidence from research using the Wilkins (MRC) system. '

The following line appears in a letter to the British Medical Journal written in response to an editorial which was critical of visual stress treatment  'they can then be tested with the MRC-patented Intuitive Colorimeter to see if coloured lenses help to a greater extent'   

Letter from a well known firm of London Optometrists -
"I tested xxxxx with the Wilkins (MRC) Colorimeter and he showed a sufficiently consistent response"

The paragraph below comes from 'anonymous' who responded to an excellent blog post by Angela Bunyi at scholastic.com 'Coloured Overlays a Rose-Colored Glasses of the Reading world'.

'Visual stress is the correct medical term. If you do a google search with the terms: Dr Bruce J. W. Evans and Arnold Wilkins, you'll find a wealth of scientific FACTS- NOT OPINIONS with numerous PUBLISHED scientific studies done under the authority of The Medical Research Council,a British Governmental Agency, which holds the rights to the Intuitive Overlays,Intuitive Colorimeter and Precision Tints'

This paragraph comes from a firm of optometrists in Birmingham. Their visual stress and dyslexia page states that -
Professor Arnold Wilkins and The Medical Council designed and carried out this research with the use of The Intuitive Colourimeter to prescribe precision tinted lenses. It is this system that is used at Eye Opticians in our consultations. The system is validated by The British Dyslexia Association and The College of Optometrists in the UK and the Federal Drug Administration (FDA) in the USA.

Or another one from a firm of optometrists in London.
Here at The Eye Place we now have an intuitive colorimeter to find the optimal precision tint needed to provide relief from visual stress. This instrument was developed by Professor Arnold Wilkins and the Medical Research Council.

What is the connection with the MRC?
At the time Professor Arnold Wilkins developed the Intuitive Colorimeter he was working at the applied psychology unit in Cambridge which was funded by the MRC. According to his' book 'Reading through Colour' this unit was disbanded when the MRC withdrew support. This is not of itself a criticism, funding is tight and sometimes even good research does not continue to attract support. That said, it does suggest that scientific peer reviewers at the MRC did not find the research on colour and 'visual stress' as compelling as its proponents do. Furthermore, if you are going to 'leverage' the reputation of the MRC to bolster the credentials of the Intuitive Colorimeter, you also have to accept that the subsequent loss of MRC funding detracts from the reputation of that product.
As is only right and proper, the MRC owns the intellectual property rights to any developments that occur in laboratories that it funds. This meant when the Intuitive Colorimeter was developed at the applied psychology unit, the patent was owned by the MRC. 
The patent (which now seems to have lapsed) can be found here and it only states that the colorimeter is 'an apparatus for obtaining a desired tint'. There is no mention of visual stress or the therapeutic use of the Intuitive Colorimeter. 
The historic link with the MRC does nothing to bolster the evidence for the use of the Intuitive Colorimeter as a therapeutic device.

Repeatability of visual stress assessments

This paper appeared in the July 2017 issue of Ophthalmic and Physiological Optics (OPO) which is the 'house journal' of the College of Optometrists. The data it contains are a major problem for proponents of the precision tinting hypothesis. You can access the abstract here at the OPO website. Although the full paper is hidden behind a paywall, John Wiley and Sons the publishers of OPO, provide access to this article for patients and caregivers at reduced cost ($3.50). This is an initiative that should be applauded.
The authors are independent and have no financial ties to 'visual-stress' treatment. It is also striking how measured they are in their conclusions. The weaknesses of the data are acknowledged as are other possible interpretations. This contrasts with the 'spin' put on the data in some of the papers that have been reviewed elsewhere in this blog.

A key aspect of the precision tinting hypothesis is that the choice of colour that ameliorates symptoms in the putative disorder 'visual stress' should be constant and repeatable. Otherwise, why would anyone spend hundreds of pounds on an assessment leading to the prescription of Precision Tinted Lenses (PCTs) if re-testing one month later were to show that a perceptibly different colour was required? This paper appears to show that the choice of colour is not repeatable and in as short a period of as one month, a significantly different colour may be needed.

The study
Twenty-six participants with 'visual stress' and no other uncorrected visual or ocular anomalies were recruited for the study. A difficulty in conducting this kind of research is that the criteria for diagnosing 'visual-stress' are an ever shifting target. In this case, they were..
i)Symptoms of visual discomfort or distortion while reading
ii)Alleviation of symptoms with a coloured overlay
Although it was not an inclusion criterion, two-thirds of participants had previously been diagnosed with visual stress and had been using overlays for a prolonged period. In addition, table 1 shows that most subjects increased their reading rate on the Wilkins Rate of reading test with their chosen overlay.
The authors, who are always measured in their conclusions, acknowledge that their criteria may have over-diagnosed 'visual-stress.' However, they also observe that 'no standard diagnostic criteria are available, quoting a review written by  Professor Evans.  The diagnostic criteria used in this study are as rigorous as many of the previously published studies on visual stress.

Subjects were tested first with Intuitive Overlays according to published method.  For some reason, starting with rose, until the overlay that best ameliorated their visual symptoms was found. Subsequently, participants were tested with the Intuitive Colorimeter which is a light tight box in which hue and luminance can be varied independently, while the subject views strings of random letters arranged to look like words. First, the participant indicated which of the 12 hue settings made the 'text' more or less comfortable to read compared to white light. Hues were then compared against each other to find the best, and then the saturation of the preferred hue was reduced to find the minimum that would ameliorate symptoms. Finally, the brightness was adjusted to an optimal setting. In all, there are 288 possible lens colour settings from which the participant chose one.
Participants were tested on a second occasion one month later....

Results
Looking at the data for overlays. On the second occasion of testing,  11 subjects chose a completely different overlay and 3 subjects chose a similar but different colour. Because one-third of subjects were already using overlays it seems likely that they already knew their chosen colour. Consequently, this part of the study is open to bias. Even so, it is striking how many participants chose a completely different colour on the second occasion of testing.
The most interesting data relates to the Intuitive Colorimeter. Because subjects did not receive their chosen lens at the first testing session and because they had not been previously exposed to PCTs these results are less vulnerable to bias. All subjects chose a different colour on the second occasion of testing that was separated by at least 3 just noticeable differences (JNDs). That is, the different colour would have been plainly perceptible. The average was 9 JNDs. This is a telling statistic because above 6 JNDs symptoms should worsen according to the existing theory.

Conclusions
The results of this study are not compatible with the precision tinting hypothesis. If the colour required to ameliorate 'visual stress' is not stable there is little point in prescribing PCTs. The study also opens up other lines of research. What does influence the choice of colour? It has already been shown the gender has an effect. Maybe test order has an effect and I would be surprised if there are no priming effects. That is, the way the information is presented prior to testing or what colours participants are exposed to before testing, might influence the participants chosen colour.
These results have to be seen in the context of another recent study from a psychophysical laboratory at Imperial College described in the blog post of September 2015 that showed that PCTs did not improve contrast sensitivity function in the range of spatial frequencies that are said to be aversive in 'visual stress'.

Criticisms
It is a little churlish to criticise this study when it is such a breath of fresh air and it has to be good to have some new and independent researchers involved in this area. Anyway.....
1)'Visual stress appears to be accepted as an established disorder like blood pressure,  diabetes or myopia for example. In fact, in spite of over 20 years of research, it remains a putative disorder that has yet to be properly defined. It is championed by only a few scientists and so far, at least, it has failed to achieve main stream acceptance. For example, there is no ICD10 code for Meares-Irlen Syndrome.  A qualifying sentence in the introduction would have been appropriate.
2) Cortical hyper-excitability is a speculative neuro-scientific theory with weak theoretical underpinnings and a poor evidence base. In my opinion, it is given undue prominence.
3) Reference 9 in the paper refers to proposed diagnostic criteria for 'visual stress'. The paper 'A Delphi study to develop practical diagnostic guidelines for visual stress' will be reviewed in a future blog. Two of the three authors had a financial interest in the treatment of visual stress. Twenty-six practitioners who were frequent prescribers of PCTs and thus also had a financial interest were invited to take part in the study. This is not a credible process because the panel of a Delphi study is supposed to represent a range of voices; this one did not. For this reason, I do not think this paper should be cited as a credible source of information or at least it should carry some kind of 'health warning.'

Perhaps these criticisms are petty and they are very much my personal view. They certainly do not detract from the paper which should be read by anyone with an interest in 'visual-stress.'

Visual Stress Deviant?

This rather odd (to my eyes) article which reports a lecture given by Professor Bruce Evans at 100% Optical  this year, appeared in Optometry Today. You can access it here

The powerpoint files associated with the lecture are available on this website. The article in optometry today also carries what appear to be direct quotes, so I think it reasonable to assume that it reflects the views of the speaker.

The article in Optometry Today relies on a familiar rhetorical device, which is used to position proponents of visual stress treatment in the centre ground of a debate. It appears that there are "zealots" who claim that visual factors cause dyslexia and "deviants" who say that vision is irrelevant to dyslexia. To be fair, the power point files use the word 'denier' rather than the inappropriate term deviant. That said, I do not think either word is ideal.

The argument depends on setting up a false dichotomy between those 'who think visual factors cause dyslexia and those who feel it is irrelevant'. I don't think anybody thinks visual factors (in general) are irrelevant; there have to be extremes of refractive error that will affect the acquisition of reading. Every day, optometrists have to make difficult judgements calls, on the basis of imperfect evidence, which children with reading difficulties require glasses and which don't.
  A link is then drawn between this somewhat banal statement and a more contentious one - as if they were equivalent. This time the dichotomy is between those who believe visual stress is a major cause of reading difficulties and those who believe that it does not exist. In the centre-ground is the statement 'maybe visual stress can co-occur with dyslexia.' Well, that is isn't saying very much. Flat feet, eating burnt toast and dandruff may co-occur with dyslexia - so what.
With regard to whether visual stress exists: if you mean do some people find stripy patterns visually aversive? The answer is obviously yes. If you want to call that visual stress Then yes 'visual stress" exists. However, whether dyslexics are more likely to experience visual stress,  whether this is a factor in their reading difficulties and whether coloured overlays and lenses ameliorate visual stress and whether that, in turn, aids the acquisition of reading is not clear - the evidence is lacking at every step of the chain.
  It is worth asking whether 'visual stress' is a widely accepted disease label? The International Statistical Classification of Diseases and Health Related Problems (ICD10) does not list 'visual stress' as a recognised disorder and neither does the American Diagnostic and Statistical Manual of Mental disorders DSM 5. It would appear that the wider scientific community is not convinced that 'visual stress' is a real pathological entity.
 That brings me to the problem with the word 'denier'. That term has come to be associated with extreme positions that go against the overwhelming scientific or historical consensus. For example, climate change denial or holocaust denial. I hope that the intention of Professor Evans was not to implant in the mind of his audience some kind of link between those who adopt a sceptical approach to his work, that is entirely appropriate, and extreme fringe views such as evolution or climate change denial. The picture of a fringe religious group (see picture above), that has no relevance to the subject under discussion, leads me to think that could be the intention. There is no scientific consensus around visual stress and for that reason, 'denier' is an inappropriate label.
  The real difficulty I have with all this is not that I am offended, it is that the arguments presented are not scientific arguments at all. They appear to me to be kind of techniques politicians use. Claim that you occupy the centre ground, link a  statement that everyone can believe with a more contentious one, and link your opponents to extremist views - in this case, deniers of mainstream beliefs for which there is overwhelming evidence.
  According to the Optometry Today article "evidence suggests that visual stress occurs in one in five people with dyslexia." This statement is not backed by any reference. There have been no epidemiological studies using the current diagnostic criterion for visual stress  (reading the Wilkins Rate of Reading Test -WRRT-15% faster with chosen overlay). So, in truth, we do not know what the prevalence VS is among dyslexics. I assume the figure of one in five is based on a problematic study that has been reviewed elsewhere in this blog in May 2015. The study was inadequately powered, dyslexics were drawn from dyslexia clubs and unlikely to be representative of the wider population of poor readers and they were not a 'naive' population in that some may have previously been exposed to visual stress assessments.
  Even if you accept this figure, it is not enough to say that 'visual stress' co-exists with dyslexia; you would expect it to be over-represented among dyslexics. A condition that results in apparent movement and distortion of print would tip an individual with borderline phonetic skills into the dyslexia subgroup and dyslexics with 'visual stress' should be less amenable to treatment by conventional educational means. There are no high-quality studies that show a statistically significant difference in the prevalence of 'visual stress' among dyslexics and normal readers.
 According to the final part of the article in Optometry Today, optometrists should consult the website of the Society for Coloured Lenses Prescribers (S4CLP). This organisation will be the subject of a future post.  It certainly is not a source of impartial information.
  Tracy Brown of Sense about Science says that "One reason quackery survives is that it wears so much of the garb of legitimate medicine and legitimate medical charities." While it would be unfair to describe visual stress treatment with coloured lenses and overlays as quackery, I think a similar argument can be applied to S4CLP which has the veneer of a regulatory body such as the General Optical Council or General Medical Council. In practice, it is nothing of the sort.