Irlen Syndrome : Types, Causes, Symptoms, and Treatments

irlen syndrome

What is Irlen Syndrome?

Dr. Helen Irlen discovered Irlen syndrome in 1987.  It is seen as a difficulty related to maintaining attention, understanding, and memorization, and to the ocular activity during the reading, causing learning deficit.

Irlen Syndrome affects people of all ages, including people with normal or above average intelligence and is related to the way information reaches the brain.

Irlen syndrome is a distortion in visual perception. Although the center of vision is in focus, presenting most often in the routine ophthalmological examination AV 20/20.

This syndrome causes the Brain processing of information arriving through vision becomes distorted and blurry, causing discomfort during reading, writing, and other routine activities.

It is known that it is through the five senses that we know the world, and it is from the vision that we can see, perceive and also encode the stimuli that come to our eyes.

In this way, when these stimuli are compromised, quality of life is lost and the individual starts to accumulate difficulties that will lead to future losses.

People with this syndrome report that brightness, contrast, glare, print size, work, and effort for continuous reading can negatively affect reading performance, as well as interfere with other visual activities.

People with Irlen Syndrome consume more energy during reading and other visual activities because they capture visual information differently from others. Unconscious strategies are used in the attempt to control such perceived failures.

Due to the effort expended in the processing of visual information, reading becomes slower and segmented, which compromises the speed of cognition and memorization.

So it can produce tiredness, inversions, word changes and loss of lines in the text, blurring, drowsiness, visual disturbances, headaches, irritability, nausea, distraction, and photophobia, after a relatively short reading interval.

In addition to reading, Irlen Syndrome can affect other areas such as copying, writing, mathematical calculations, spelling, and computer use. Excessive energy expended during reading can also affect attention, motivation, concentration, and performance.

The symptoms of Irlen Syndrome are not detected by conventional tests of perception, reading, psycho-pedagogical, clinical or ophthalmologic evaluation; also do not improve with age, with the use of medication or other treatments.

Types of Irlen Syndrom

  • Sensitivity to light: Intolerance to white, fluorescent light and headlights, causing glare. Luminosity seems to cause sensory fatigue resulting in distortions, attention deficit, and concentration, anxiety, tiredness or other physical symptoms.


  • Accommodation: White pages look bright and seem to compete with the impression, nullifying it. This results in a variety of distortions, making it difficult to read and causing discomfort.


  • Distortions: Letters, words, numbers or musical notes lose clarity and stability. Distortions include vibration, pulsation, movement or blurring, but are not restricted to such symptoms; which may affect reading comprehension.


  • Restricted cognition: Inability to see letters, words, musical notes or grouped numbers, and can vary between seeing a group of words or perceiving one letter at a time. Restricted cognition can affect the ability to correctly identify letters, maintain fixation, and read speed.


  • Misperception: There is the loss of clarity, stability, and dimension of objects. Difficulties can affect the perception of depth and distance or the ability to follow moving objects. Restrictions can cause problems with steps, escalators, sports, and drive.

 The Relationship Between Irlen Syndrome and Dyslexia Syndrome

Parents whose children have difficulty reading, therefore been identified as dyslexics should beware and insist on diagnosis. The problem can be curable and the child is actually part of 15% of the population with Irlen syndrome.

All the small impacts, mainly because it affects the coordination of the ocular movement, and, consequently, it impairs the reading. Like dyslexia, it manifests itself with varying intensity, but it is a clinically demonstrated ophthalmic problem that has treatment.

The first concept of dyslexia is authored by the British physician W. Pringle Morgan and was described in the late 19th century to identify children who could not read despite access to a good education. The modern diagnosis also has a vague and wide description. it is a complex neurological syndrome that manifests itself in an extremely heterogeneous way.

Doctors point out that all cases of Irlen syndrome that are not identified as such end up diagnosing dyslexia. In general, we see a tendency to use this classification as any condition that affects learning and about what is not known exactly what it is.

It is more a diagnosis of exclusion – it is nothing more, it is dyslexia – than actual affirmation. It is a non-medical, but an educational term, to speak of the difficulty of reading. The great effort we make is to get Irlen out of this common bag.

DIFFERENTIATED TEST  explains that, in these cases, it is necessary to test the vision in operation, contrary to classic ophthalmology examination. The assessment should exclude instability of eye movement. “When we read, we usually move our eyes three to four times a second.

To know whether the person reads or not, I can not help seeing whether or not he sees the fine print, but if he sees and moves his eyes from left to right at a fast and steady speed and with both eyes in sync “He says.

The doctor adds that often the difficulty that turns into an aversion to reading is related to the contrast of white with black on paper, leaving the child not knowing what to pay attention.

Sufferers cannot adapt to the contrast (light and dark or black and white). And in this work, they tend to have distortion of perception, feeling as if the text is moving and the word, trembling.

The diagnosis of Irlen and dyslexia must be made separately. Whoever perceives dyslexia is the teacher and the pedagogue and, only recently, has become a medical problem. But in the literacy test, only about 15% of the visual information involved in learning is met. The rest is not considered.

Reading is the basis of learning in our society. When they can not learn, the child ends up being cut off from the process of social integration and goes to at most elementary school. The eye is tearing and scratching. The student is looking for an alternative, is dispersed, starts to move in the chair, is labeled as inattentive, uneducated, hyperactive and ends up leaving school.

The tests were done at the hospital verify how the child sees with natural and artificial light. In the fluorescent light, the boy sees the letter moving.

By means of specific color transparencies, these distortions are eliminated, leading immediately to a more fluent and comprehensible reading. Doctors point out that transparencies are an assistive, non-invasive resource.

Doctors warn that not all ophthalmologists are able to detect Irlen syndrome in their offices. The sub-cortical part of the disease-related view is still a “hidden part of the iceberg,” hence the difficulty of many professionals in understanding it.

“What is compromised is the sub-cortical vision, which gives us guidance. What we study in the office is the cortical, the ability to classify objects,” he explains.

Related: Sensory Processing Disorder -SPD: Causes, Symptoms, Treatment

 Irlen Syndrome

Learn the causes of Irlen Syndrome

Irlen syndrome is caused by several types of imbalances in the ability to adapt to light. It is manifested mainly by reading deficit and photophobia.

In 84% of the cases the SI is hereditary, and if only one of the parents has the condition the person can already be affected by the dysfunction.

But why does this inability to adapt to light occur? Let’s look at the following hypotheses:

  • Retina: This area of the eye has several layers of light-receiving cells. They are responsible for turning lights into color. They also “translate” the components of the images, helping us to distinguish the edges, shapes, and contours of objects. Moreover, it is the retina that determines the intensity of what we see. For all this, it is clear that retinal malfunction can cause the condition.


  • Eye movement: As we read or closely observe an object, the eyes move to extract various information. By analyzing the pattern of eye movements, it is possible to aid in the differentiation of people who can easily read from those who have different degrees of difficulty reading.

Irlen Syndrome Symptoms

The symptoms cause a lot of discomforts and do not improve with age or with the use of medication. Are they:

  • Anxiety;
  • Nervousness;
  • Attention deficit;
  • Low ability to concentrate;
  • great difficulty driving in the dark;
  • Dizziness, nausea, stomach pain and  headache  at the time of reading or performing various tasks that require the attention of the eyes – including performing routine habits such as climbing stairs;
  • A great difficulty in following moving objects;
  • Commitment to perceive the depth of objects (stereopsis);
  • Sensitivity to any type of lighting (photophobia – such as  keratoconus ), such as stronger lights, sunlight, car headlights and street lighting at night;
  • Great effort with associated stress in performing various activities, such as distinguishing colors or using computers for a long time;

Eye Strain: visual and present stress with differences, only in intensity. Extreme tiredness causes visual discomfort and is associated with dryness and burning sensation in the eyes. Causes redness, tearing, drowsiness, need to tighten and scratch the eyes and take many breaks to rest the vision. Also change the distance of the printed paper frequent.

Related: Sanfilippo Syndrome: A Rare and Devastating Disorder

Irlen Syndrome Treatment

Treatments are aimed at relieving symptoms and thereby improving the quality of life of the patient as a whole, including school and work performance, as well as performing simple tasks such as climbing a ladder.

There is no treatment that works the same way for all patients because the disease manifests itself in different ways for each person.

The most effective treatment is the use of special translucent and colored spectral filters (called overlays) – in pink, yellow, blue or green – that neutralize the contrasts with the different types of luminosity.

Available filter formats

Glasses: Facilitate reading (far and near) and improve the perception of objects;

Plastic Sheets: when placed in front of computer screens or on documents and books, they make reading and typing easier.

Setting the ideal filter color

The purpose of the filter is to neutralize the visual distortions by interposing transparencies of different colors during the consultation with the ophthalmologist. The patient will select the color that is most comfortable for the test.

What do filters do? Because of their specific color, the overlays cut a certain wavelength that, for some nonspecific reason, causes the so-called “noises” in the visual system. When cut, the wavelength corresponding to a certain hue is inhibited, bypassing all discomforts.

The red filter, for example, blocks the bluish wavelength and the blue filter cuts the lengths in red.

In addition to the overlays, usually medical, pedagogical and psychological techniques and interventions are used to relieve symptoms and to accept the need to live with the problem – such as the possible embarrassment of wearing glasses with colored lenses.

Download Color-Overlay Software


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