Using functional brain imaging for an improved understanding of Irlen Syndrome

Research Related to Irlen Syndrome

Go to THIS LINK at Evans Consulting

A Magnetoencephalographic Investigation of Visual Information Processing in Irlen’s Scotopic Sensitivity Syndrome



by Jeffrey David Lewine, Ph.D, John Davis, Ph.D., Sherri Provencal, M.A.,

James Edgar, M.A., and William Orrison, Jr., M.D.

Conducted at The Center for Advanced Medical Technologies, The University of Utah School of Medicine,

Salt Lake City, Utah, and Department of Psychology, The University of New Mexico, Albuquerque, New Mexico

Many persons with poor reading skills and habits demonstrate significant visual fatigue and discomfort when

observing high contrast, high luminance stimuli. Dizziness, headaches, strain or fatigue are some of the

ancillary findings in Scotopic Sensitivity/Irlen Syndrome (SSS) that compound reading difficulties. Under high

luminance conditions, words distort. They may float above the page or jumble into a wavy, incomprehensible

tangle. The background may pulsate or eradicate parts of letters. Several behavioral studies demonstrate that

many of the deleterious aspects of the condition can be alleviated by wearing colored Irlen lenses, the best color

being different for each patient.

At present, the relevant physiological mechanisms are unknown; but presumably they are related to altered

visual information processing. In this study, magnetoencephalography (MEG) was used to characterize visual

responses in conditions with and without lenses. Steady-state visual evoked magnetic fields were recorded from

8 subjects with SSS and 8 normal control subjects using a 122-channel, whole-head biomagnetometer. During

the testing, subjects fixated the center of a 4 square checker board that contrast reversed every 200 msec. There

was a small black circle at fixation that briefly flashed white every 1-2 seconds, and subjects were instructed to

count flashes.

For the SSS group, each subject was evaluated with and without custom colored Irlen lenses. Control subjects

were tested without lenses and with a lens pair that caused the maximum change in luminance. In all cases, the

evoked magnetic signal reflected a complicated pattern of bilateral activation of multiple cortical generators. A

major difference in with and without lens conditions was seen between 170 and 200 msec post-stimulus.

For normal subjects, without lenses, the field pattern at this time was mostly dipolar and reflected midline

calcarine activity. When lenses were on, the pattern was much more complex, reflecting multiple generators.

The reverse situation was seen for 6 or 8 subjects with SSS. That is, a complex field pattern was seen without

lenses, whereas an organized dipolar pattern was seen with lenses.


Note: Sorry, but I could not get the formatting  resolved.  Roger Wheaton

Brain Scan Showing Effect of Scotopic Sensitivity Before and After Wearing Irlen Lenses

See this excellent brain scan within the article “What is Irlen Syndrome?” Notice the large white areas illustrating how hard the brain is working to perceive without Irlen filters.

Read about brain scans by referring to Neuroimagery on Wikipedia

Some Links to Abstracts of Research on Irlen Syndrome

Reading Disabilities and the Effects of Colored Filters

The Effects of Irlen Colored Lenses on Students’ Specific Reading Skills and Their Perception of Ability: a 12-Month Validity Study

Scotopic Sensitivity Syndrome/Irlen Syndrome and the Use of Coloured Filters: a Long-term Placebo Controlled and Masked Study of Reading Achievement and Perception of Ability

Some Research and Other Papers Relating to Irlen Filters and Irlen Syndrome   (Scroll to bottum)

Irlen Filters and Reading Strategies: Effects of Coloured Filters on Reading Achievement, Specific Reading Strategies, and Perception of Ability

Migraine Research Findings

Read reports of results at IRLEN.COM

Brain Imaging Studies of Irlen Syndrome

Go to several sources at THIS LINK.

“Light and the Brain” article by Daniel Amen M.D. in his Brain in the News Newsletter

This article gives a good description of what is encountered with Irlen Syndrome and results of before and after brain imaging studies done with Irlen patients.

Read about completed and ongoing research about Irlen Syndrome

by visiting

Connections Between Irlen Syndrome and Other Medical Conditions According to the Amen Clinic

Amen Clinics and Brain Scans


The Amen Clinics have amassed the world’s largest database of brain scans related to behaviour, more than 21,000. The brain is involved in everything we do. The clinics include screening for Irlen Syndrome in their assessments and testing. Dr. Robert Dobrin describes below the links he has found between Irlen Syndrome and a range of conditions. This is further evidence that Irlen Syndrome needs to be better understood by professionals and that testing for Irlen Syndrome needs to be incorporated into standard testing procedures.

“The Irlen Syndrome represents an intriguing and controversial spectrum of symptoms that remain invisible to most clinicians. During the last 32 months at the Amen Clinic, I have confirmed diagnosis of approximately 210 patients with Irlen Syndrome. Irlen Syndrome, depending on the severity and presence of co-existing disorders, contributed to anxiety, with a resulting spectrum of fatigue, irritability, and vulnerability with a diminished cognitive reserve.

Irlen Syndrome should be expected within the following clinical composites: