Scotopic Sensitivity Syndrome–An update

by Siegfried Othmer | July 28th, 2005

We just attended the annual conference on Irlen Syndrome, sponsored by Helen Irlen and her staff, and held here in Long Beach. This was the twentieth anniversary of Helen Irlen’s work, subsequent to her discovery of Scotopic Sensitivity Syndrome in 1983. The conference was a warm and spunky affair. There was still the sense of “us against the world” in the air, but also the swagger of great self-confidence. The remaining adversary in the world at large was nothing more formidable than ignorance itself.

Scotopic Sensitivity Syndrome refers to the condition in which individuals find their vision compromised, particularly in reading, under bright light or simply full spectrum light conditions. This may present a particular problem with high spatial frequencies in the visual field, such as steps on escalators, hotel carpets, or as encountered in written material. Words may move; lines may flow into each other; the spaces between words on the page may merge into large-scale gestalts (rivulets down the page), etc. The condition is easily screened for, and the straight-forward and categorical remedy is to limit the spectral input to the eye in some fashion so that the person can see normally. This can be most inexpensively done with colored overlays, and more assuredly with properly fitted colored-lens eyewear. In the absence of a proper diagnosis, people nevertheless may find their way to a remedy, such as preferring a darkened room for reading, favoring certain colors of sunglasses, and avoiding bright scenes as much as possible.

It is estimated that some 100,000 people are now running around with Irlen lenses. That is success of a sort indeed, except when it is compared to the estimate that some 20% of folks have a type of visual processing that could be affected by Irlen Syndrome. Helen herself looked at the downside of her enduring campaign: “In twenty years, we have lost another generation of children who could have been helped.”

There have been some similarities in the development of Helen’s work and ours in neurofeedback. Helen also found a more favorable climate for her work early on in Australia than at home. The Australian version of “60 Minutes” did a show on “Seeing through Rose-Coloured Glasses,” and it received the greatest audience response that they had ever experienced up to that time. The program staff sent Dr. Paul Whiting, their resident expert, to LA to investigate the program, and as a result he then established the first Irlen Center at the University of Sydney.

Later the American “60 Minutes” program wanted to follow up, but Helen demurred. That program was known for knee-capping almost anything that they covered, and she was at that time still early in her research on the method. This was being conducted at California State University at Long Beach. Premature publicity could have been fatal. So “60 Minutes” approached Channel 9 in Australia about simply re-showing the Australian program, but Helen managed to forestall that end-run. When 60 Minutes finally did their show in 1988 they also received the largest audience response that they had had to date.

A controlled crossover design was done in Australia by Dr. Greg Robinson, accompanied by other intensive dyslexia remediation techniques, with a focus on the visual-perceptual subtype of dyslexia. After a combination of Irlen overlays plus three months of intensive remediation, experimentals showed gains in comprehension ranging from one year two months to one year seven months, versus no gain among the controls. Then the control group got overlays and caught up in three months. This group showed even larger gains. The test instrument was the Woodcock-Johnson.

There were the usual highs and lows along the way. General Motors recognized Irlen lenses as one of five major innovations, which they then featured in a video as a way of spurring innovation among their employees. On the other side, a school in Arkansas decided that a child could have nothing to do with overlays in the school. The parents took the school district to court and won. Now there is a bill in the Arkansas legislature that mandates Irlen screening for school children. The low point was reached when optometrists went after Helen Irlen big time, accusing her of practicing optometry without a license. They hectored every state attorney general, and every local district attorney around the country. Apparently they managed to break through in Florida.

It will be observed that optometrists are not currently screening for or offering Irlen lenses. They just did not want what they saw as competition, even though Irlen’s work has nothing to do with optical correction. Thus is the public interest served by professional groups. Even Orton Dyslexia Society looks askance at Irlen Syndrome because the organization prefers its own perspective on the nature of dyslexia.

While we are reviewing ancient history here, let’s throw in that we heard Helen Irlen during the late eighties at a conference of the Learning Disability Association, one of the few organizations that welcomed alternative perspectives (and to which we owe our initial awareness of Margaret Ayers’ work with neurofeedback). What Helen says is certainly startling on first encounter, but she came equipped with recorded observations on both children and adults whose ability to read was startlingly affected merely by putting on the special glasses. Either she had hired herself some excellent child actors, or there was something significant going on here.

At a subsequent meeting of the LDA here in Los Angeles, we heard Larry Silver (later to become President of the organization) denounce Irlen lenses as ineffectual. He threw that in for good measure after denouncing the Feingold diet. His loud and vigorous challenge that the Feingold diet was ineffective in managing ADHD was followed by the sotto voce remark, “with the exception of a small percentage of children,” which almost certainly could not be heard by the audience or on the tape. He could depart the podium in the conviction that he had been honest, but he certainly was not honest in the impression that he had left.

I happened to hear it because I was sitting up front, so I took the opportunity to approach the podium for a response. “Why are you coming up here?” Silver drew back, feeling threatened. “To use the microphone,” I answered. I asked the rhetorical question of Silver: “Do you know how ridiculous you must appear at this moment to people in the audience who are looking at you through Irlen lenses?” The audience of course loved it, although at the time there cannot have been very many such people. The curtain just has to be drawn back on these Wizards of Oz, posturing sagely with an assumed air of competence. What could Larry Silver possibly have known one way or the other about Irlen Syndrome at that time? People like Silver arrogate to themselves the awesome burden of always knowing what’s best for people.

One more anecdote will bring us up to date. Some five or so years ago I heard Jeffrey Lewine of the University of Utah Center for Advanced Medical Technologies talk on Irlen Syndrome at a Conference on Innovations in Education being held in Salt Lake City. He had been implored by Helen Irlen to utilize the new magnetoencephalography (MEG) installation at the university to investigate Irlen Syndrome. At the time it was just one of about three to five such installations in the whole country. Lewine had resisted one overture after another from Helen for many months, but eventually relented. There was an ongoing study on autism, and they were able to just fold a few other subjects into the program.

Among those children exhibiting the Irlen Syndrome there was indeed a difference in their response to a pulsed visual signal. The MEG visual evoked potential in the association area V5 had a different time course and the processing took place over a larger cortical volume. This last feature could not have been determined from EEG measurements (because these measure effects only at the cortical surface) or any other imaging technique (because they are too slow). The difference showed up only in the range of 180msec to 240msec post-stimulus. Lewine could convert abnormal into normal performance when the children put on their Irlen glasses, and could convert back into abnormal performance by placing them in the offending lighting environments. Matters were entirely reversible.

For years thereafter, these results remained unpublished. Lewine did not need the grief that publication would bring. Unsurprisingly, I found these data to be completely persuasive. The import for Helen’s continuing work was that these findings shifted the attention to post-retinal processing of the visual signal. Perhaps the syndrome did not involve “scotopic sensitivity” at all. The term “Scotopic Sensitivity Syndrome” was henceforth down-played in favor of the less tendentious “Irlen Syndrome.”

Ironically, it was only after this eye-opening encounter in Salt Lake City that Sue realized she had been suffering some of the symptoms characteristic of Irlen Syndrome. Screening confirmed it. Special coating for her glasses was ordered. This was also an indication that neurofeedback is unlikely to remediate the condition. After all, by this point Sue had done years of neurofeedback training.

Chris Chase of Claremont McKenna College illuminated a possible model for Irlen Syndrome. He was working under a grant from the National Eye Institute. It has been found that there is a distribution in ratios of the different color receptors (cones). As was first demonstrated by Edwin Land of Polaroid fame, the brain really makes up most of the color spectrum through the weighing of relative fluxes perceived by the three cone types. When the retinal populations are too far out, this normalization process may not be able to function fluently. The neural system combines inputs from different color cones in a center/surround combination. Some eight combinations are formed, leading to our perception of four basic colors even though there are only three types of cones. Yellow is constructed of a combination of a blue center and a red/green surround, or the reverse. Our ability to see yellow is therefore entirely dependent on the working of this higher level of processing, at the level of the retinal ganglion cells.

The cone ratios can be easily determined post-mortem, or by sacrificing an eyeball. But when one wishes to correlate such ratios with reading performance, this cannot very well be done with humans. Chase devised an optical threshold test that gets at the same ratios. He found a distributional match to the distribution known from prior post-mortem measurements. Thus encouraged, he correlated the ratios with reading performance by Irlen criteria. There was an excellent correlation.

In the cohort of college students being evaluated, some 17.4% were found to have mild to moderate Irlen symptoms. And reading is their job! Some four different symptom patterns were identified:

Type 1 (33%) is characterized by headaches and sore eyes, with complaints of text distortion (blurring or doubling of images). Type 2 (21%) complains mainly of glare, of slow reading speed, and the frequent need to read passages over again. Type 3 (36%) is similar to Type 1 but not does not complain of headaches. The fourth type (10%) shows mixed symptoms across the board. What it boils down to is that the more red receptors one has, the more difficult it is to read. This proportion can vary from 30% all the way to 90%. This observation may explain the prominence of blue-tinted lenses in the population or Irlen users. The prominence of yellow filters may have to do with the indirect way in which yellow is processed, as already alluded to. But the specificity of what is required for each person stands as an abiding indictment of any simple explanations.

This work, definitive though it was, was “met with polite skepticism.” One problem that we also have in neurofeedback is that tailoring of the remedy to the client is required. Type 1 is most commonly responsive to blue-tinted lenses. Type 2 requires broadband filters or a Polaroid filter. Or one simply works with a more benign light source. Type 3 responds to yellow-tinted lenses. Such a state of affairs means that “You’re in business as a clinician, but you’re out of business as a researcher.” As it happens, Chase has not been able to get this work published to date, despite having a number of other universities as collaborators on one or another aspect of the project. His paper is now in its fourth revision.

Daniel Amen was an invited speaker at this conference, but he gave a rather general talk that does not need to be covered here. Significantly, he showed a pre-post comparison of SPECTs with and without the Irlen lenses in someone with the syndrome. The difference was stunning. This was of course sufficient to convince him, since he is conversant with his own assessments. Irlen screening is now routinely done at his centers. The next day Robert Dobrin, MD, a psychiatrist working with Daniel Amen, talked more technically about the work. He first got interested in Irlen work when a bright bespectacled 9-year-old came into his office some years ago sporting Irlen lenses. Dobrin asked about them, and the kid insouciantly answered: “You’re the child psychiatrist; you should know!” Indeed. So Dobrin was embarrassed into investigating the Irlen approach by a nine-year-old patient. He has never looked back.

Dobrin undertook a thorough investigation in which some 460 patients were screened preliminarily using some 17 questions selected from the Irlen questionnaire. This was over a three-year period. 210 of these ended up diagnosed with Irlen syndrome, and in 120 the condition was moderate to severe. Forty of these ended up getting the Irlen lenses.

James Irvine is a military guy, currently residing at China Lake, who got interested in this work because the Armed Forces often put soldiers, sailors, and airmen under strange lighting conditions aboard ship and in the bellies of aircraft. If these policies were disadvantaging some people and rendering them dysfunctional, that needed to be known.

Irvine went back to the old research on the human visual response to color. Masses of people had been studied, and when the data were compiled there was a significant problem of outliers. The response of the researchers at the time (around 1930) was the obvious one: do more studies. But adding numbers to what was already a statistically meaningful cohort was no way to make outliers go away. Eventually the resolution was to simply segregate some 22% of subjects into this anomalous category and to evaluate the rest to establish normative curves. Ever since, the assumption has been that the human color response is reasonably homogeneous except for the readily identifiable problem of color blindness. Now it turns out that this same 22% is the very cohort of interest in the Irlen Syndrome. For these people, the accommodation function performed by the brain does not quite cover the subject. For these folks, perception is altered as a function of spectral input. If the variability in the data had been highlighted originally, we might have been sixty years ahead now instead of twenty years behind.

Irvine appears to be a glutton for data, which is fortunate since it appears to be necessary to delve into various subtypes of response characteristics, and these are also functions of intensity. It’s a large variable space. He determined the activation energy for each type of cone, for each “cone-specific filter. He then plugged this into some eighteen different models for human vision. The only fit obtained was for the “receptor field model” that also accounts for the Irlen Syndrome. In fact he obtained a high correlation between reading speed and color intensity/color balance. Yet when he too tried to promulgate his findings, he was told there were no data. “I have data. How can you say that data do not exist.” Spoken like a true engineer.

The data go further. There is also a dependence of lateral eye span, the lateral distance on the page that can be “taken in” by the eye in one glance. And most surprisingly, there is even a dependence on the preferred focal distance for near vision as a function of spectral content. Change the color of the light, and the person will promptly adjust how far away the reading material will be held away from the eye.

Absent Irlen Syndrome, there should be no dependence of reading speed, eye span, and focal distance on color content or intensity, and for “normals” that is generally true. But for the vulnerable population, the variation in reading speed alone was from 65% to 145%. That by itself proves that there is a problem to be solved. To date, even that has not been acknowledged by the mainstream. If you don’t acknowledge a problem, then of course Helen Irlen can only be a charlatan. One reason that the problem escapes the ophthalmologists is that they typically test under dim light conditions. It is quite possible that they were originally conditioned to this practice by Irlen Syndrome people….

So, what are the implications for us? First of all, it is by now apparent that the problem does in fact trace back to retinal architecture, and therefore is not just a matter of the efficiency of post-processing in the association cortex. But the latter problem exists as well, and that’s where neurofeedback might help. It is not surprising to find that people with disregulated brains have particular difficulties with Irlen Syndrome. This would include first and foremost all those with sensory hyper-excitability. A high percentage of our autism spectrum people and our migraineurs have problems with Irlen Syndrome, as do the head-injured, and people with irritable bowel. Since the “back-end” problem can be modeled as a sensory integration problem, even if it exists solely within the visual system, it is only too likely that Irlen Syndrome should correlate with other sensory integration deficits. That’s what we observe. Also anxiety correlates. Neurofeedback can help with the back-end processing problem, but there is no good alternative at the moment to solving the problem at the front end with correction of spectral input to the eye. Every neurofeedback practitioner should be screening routinely for Irlen Syndrome. Our work may very well not succeed at all unless that is taken care of.

Head injury is a particularly instructive example, since the retinal architecture remains a constant throughout. All that can change as a result of the head injury is the post-processing efficiency, which therefore should ideally be fully remediable. And the tie-in to anxiety may be an instance of the processing inefficiency in visual cortex having an impact on other regulatory networks. The tie-in to anxiety puts us on notice to survey all conditions of over-arousal, and indeed Reactive Attachment Disorder is also associated with Irlen Syndrome severity. Disregulation begets disregulation, and improved regulation anywhere can promote improved regulation everywhere else. No stone should be left unturned when it comes to training the system back toward good regulation.

In summary, the parallelism here to our own experience is in some ways uncanny. The speakers generally manifested a very clinical and problem-solving orientation, but also one that was very respectful of the need for scientific investigation and responsive to the results of such investigations. This has by now occupied some twenty years, a period of time that has given mainstream practitioners plenty of opportunities to be “snagged” by intriguing data, just as Dr. Dobrin was, and as Helen Irlen was originally. It would be ludicrous to consider this body of work collectively and pronounce it deficient in some way, undeserving of any attention. It is not a matter of needing the data to be just a bit less ambiguous. In particular, it is not a matter of controlled studies not having been done. Controlled studies are easily done in this case: glasses on, read; glasses off, read some more. What could be easier? Yet mainstream science is still missing in action.

The fault, if any, lies elsewhere. So, I conclude once again that it would be a terrible mistake for us to do anything at all except what we decide is important by our own lights; to answer the questions that we ourselves frame about our work. If we had the perfect blinded controlled study of neurofeedback, we would be no better off than Helen Irlen is today. It’s all about the paradigm. As Einstein said, “it is the theory that tells us what we may believe.”

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“There is a principle which is a bar against all Information, which is proof against all arguments, and which cannot fail to keep a man in everlasting Ignorance—that principle is contempt prior to investigation.” — Herbert Spencer
NIH Consensus Statement (1998):
“Cognitive exercises, including computer-assisted strategies, have been used to improve specific neuropsychological processes, predominantly attention, memory and executive (reasoning) skills.”

One Response to “Scotopic Sensitivity Syndrome–An update”

  1. EARLINE REMIE says:


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