top of page

What is the difference between Dyslexia and Irlen Syndrome?

Struggling readers are commonly misdiagnosed as Dyslexic when they actually have Irlen Syndrome. Research shows that 46% of people with reading problems have Irlen Syndrome, but it often goes undetected.  This is due to symptoms that are common to both disorders such as difficulty with reading fluency and comprehension.  However, interventions used to correct Dyslexia do not work for people with Irlen Syndrome.  It can be devastating for individuals who go through years of specialized reading instruction and tutors only to make little to no progress.  Basically, the difference is that Irlen Syndrome is perceptual processing disorder whereas Dyslexia is caused by a deficit in the phonological component of language.  To make this even more confusing, some individuals can have both disorders.  The good news is that the accommodations used to correct the effects of Irlen Syndrome are often immediate and dramatic.  It's important that educators and parents ensure that children who are struggling with reading get proper screening so a significant barrier to learning can be removed prior to more invasive remediation strategies that may not even be needed.  

For a more in-depth information read Do I Have Dyslexia or Irlen Syndrome? at

Visit for more information about Dyslexia.

What is Irlen Syndrome?


Irlen Syndrome (sometimes referred to in the literature as Meares-Irlen Syndrome, Scotopic Sensitivity Syndrome, or Visual Stress) is a problem with the brain, not the eye. It is a perceptual processing disorder, not a visual problem, a finding that the most current brain imaging research supports. In simplistic terms, when an individual suffers from Irlen Syndrome, their brain has difficulty or an inability processing certain wavelengths of light. In this way, light (especially bright and fluorescent lighting) becomes a stressor on the brain. This stress causes certain parts of the brain (e.g., the visual cortex) to become overactive. It is this over-activity and inability to effectively process visual stimuli that creates a variety of visual, physical, cognitive, emotional, and neurological symptoms. 


As one might expect, symptoms of Irlen Syndrome include difficulty with reading and comprehension, issues with stability and clarity of print, and difficulty with high contrast (black print on white paper, patterns). But because Irlen Syndrome involves the brain’s inability to process all visual information it receives, and the stress on the brain can have a cascading effect throughout the entire body, it affects much more than just reading. Irlen Syndrome can also result in significant physical symptoms, such as headaches, migraines, nausea, fatigue and anxiety, as well as difficulties with math computation, handwriting, copying, reading music, depth perception, sports performance, listening, attention and concentration. 

Can my physician or eye-doctor test me for Irlen Syndrome?


Irlen Syndrome is not identified by current educational, psychological, ophthalmological, or medical tests. In fact, many individuals with Irlen Syndrome go unidentified well into adulthood, simply being told they are dumb, stupid, or lazy because all the tests show there is nothing wrong with them. When left untreated, Irlen Syndrome can lead to school failure, unrealized adult potential, and, research suggests, even a path into the criminal justice system.


Why should I get Irlen Filters when the Overlays are so helpful?


The feedback we have from clients who have received Spectral Filters (worn as glasses) is that the Spectral Filters are more convenient, more effective and can to be used in many more situations.  The precision of the Filters is greater than the Overlays since there are more than 50 different color choices which can be combined almost infinitely; there are only 10 different Overlay colors to choose from and combine.  Overlays are harder to manage, get scratched more easily, don’t always fit the book size, fade, get fingerprints on them which are hard to remove, etc.  Spectral Filters will help clients who have difficulty copying from blackboards or overhead projectors; who find computer screens are too bright; who need to do a lot of writing; who get headaches from fluorescent lights; and who have distortions in depth perception related to Irlen Syndrome.

​Can I have my eye-care professional tint my glasses the same color as my overlay?


The diagnostic process we use to determine exactly the right Spectral Filter for each individual is a long and complex process which takes a minimum of two to three hours.  It is not a simple matter and vision care specialists are not trained to carry out this process which considers the effect of the Filter on reading and writing-based activities.  In addition, the final color of the Filters is seldom the same as the overlay color as they use different types of light (one uses reflected light, the other refracted light).  In fact, attempting to put the overlay color into a pair of tinted glasses may end up causing more distortions and more eyestrain and we highly recommend that you avoid doing this.

What will it cost?


The initial cost to get the Irlen Screening is $125 which includes a set of prescribed colored overlays. There is some variation in the cost for the Irlen Spectral Filters worn as glasses, which is usually around $650.  This does not include the cost of frames.  $400 of this is for the diagnostic procedure itself (which often takes up to 3 hours).  The additional cost is for the lab fees that include the actual tinting process; for lenses; for scratch coats and UV filters if they are needed; and for mailing costs.  We understand that to some people that this may seem to be an expensive procedure.  However, when you consider how much can be spent in other approaches (tutoring, vision therapy, special schools, etc.) and weigh that against how immediately effective the Irlen Filters can be, it is really money well spent.  The fees may be charged, if preferred.  Some individuals have used their Health Savings Account.  In some cases, it is possible to apply for financial aid.


Can I tint the glasses that I already wear?


The glasses which we tint must be made of clear CR39 plastic and they should not have any scratch coats, UV filters or other tinting (like photo-grey) in them.  (We test you for the effectiveness of a UV filter and put it into your Filters if it is beneficial to you.)

If you have prescription glasses, these can often simply be tinted as they are.  However, if you already have a scratch coat, photo-grey qualities, etc. in the glasses we will not be able to guarantee the tinting process.  It would be preferable if you bring your frames and your prescription and the Irlen Institute Lab will provide the prescription lenses and then tint them.

If you choose to have your eye care professional provide your prescription lenses for insurance purposes, you will need to take this letter with you to your appointment so that you get a type or brand of lenses that can be tinted.  Have your doctor sign the form which will be sent with your glasses to the lab for tinting.  (form)

If you do not need a prescription, you may bring your frames without lenses.  The lab of the Irlen Institute will provide the non-prescription lenses and tint them appropriately.

Sometimes clients prefer to wait and see what color their tint will be before choosing frames so that the colors will be compatible.

bottom of page