Meares-Irlen Syndrome/Visual Stress (MISViS)

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Article initiated by:

Kathryn E. McAnnis, Skyler Muchmore

All contributors:

Andrew Go Lee, MD, Caitlin Makenzie Hackl, Noor Laylani, MD, Pamela Davila-Siliezar, MD, Nitin Rangu, Osama Al Deyabat, MBBS, Nagham Al-Zubidi, MD, Noor Laylani, MD, Osama Al Deyabat, MBBS, Sanjana Jaiswal

Assigned editor:

Osama Al Deyabat, MBBS

Review:

Assigned status Up to Date

 by Osama Al Deyabat, MBBS on September 10, 2024.

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Contributing Editors:	add

MISViS is a visual-processing disorder with a history of controversy with American and Australian/New Zealand Ophthalmology organizations.

Disease Entity

Meares-Irlen syndrome/visual stress (“MISViS”), also known as Meares-Irlen syndrome, Irlen syndrome, scotopic sensitivity syndrome or visual stress, is described as a visual-processing disorder characterized by difficulty with reading. MISViS was initially believed to be a subset of dyslexia; however, studies have suggested different cognitive etiology leading to controversy surrounding the condition.

Epidemiology

The entity of MISViS was first characterized in the early 1980s, individually by Helen Irlen and Olive Meares. Multiple studies have been conducted to assess the prevalence of MISViS in the United States, England, and Australia, with estimates ranging from 12% to 15% among the general population and up to 40% among individuals with dyslexia. However, these studies often exhibit inconsistencies in their design, the diagnostic criteria used for MISViS, and the reliability of their findings, which leads to variability in the reported incidence rates.

Controversial Aspects of MISViS

In a joint position statement by the American Academy of Pediatrics (AAP), American Academy of Ophthalmology (AAO), and American Association for Pediatric Ophthalmology and Strabismus (AAPOS) concluded the following in July 2014 reaffirmed their 1984 statement:

• “Scientific evidence does not support the efficacy of eye exercises, behavioral vision therapy, or special tinted filters or lenses for improving the long-term educational performance in these complex pediatric neurocognitive conditions. Diagnostic and treatment approaches that lack scientific evidence of efficacy, including eye exercises, behavioral vision therapy, or special tinted filters or lenses, are not endorsed and should not be recommended.”
• “Many of the studies that have been cited as proof of Irlen-lens efficiency have actually been inconclusive after deeper analysis. The evidence does not support the effectiveness of tinted lenses and tinted filters in these patients because of the weaknesses in methodology and statistics, variability in techniques in the trials, and the largely negative results.”

In April 2015, ophthalmologists in Maine stopped legislation to create a pilot program to screen for Irlen syndrome in elementary schools.

In April 2018, Royal Australian and New Zealand College of Ophthalmologists (RANZCO) released a position statement stating that there is no evidence that Irlen Syndrome exists and that there is no proof that supposed treatments, such as Irlen lenses, help those with reading difficulties.

Etiology

Currently, there is no strong evidence of a clear etiology of MISViS and the precise underlying mechanisms remain ill-defined. Some authors have proposed an autosomal hereditary component or genetic marker in apolipoprotein B-100 (APOBM). Additional evidence of a genetic influence is supported by a previous study reporting that 81% of children screened for MISViS had at least one parent with similar symptoms and 76% had at least one sibling displaying the same symptoms.  However, more research is needed to confirm these studies.

Risk Factors

Possible risk factors for these visual symptoms reported in patients with MISViS and others include other learning deficits, traumatic brain injury (TBI), as well as headaches/migraines.

Pathophysiology

As stated above MISViS remains highly debated. The existing literature is unclear if MISViS exists separately as a distinct entity from dyslexia or other visual processing disorders. Several theories, however, have been proposed regarding its pathophysiology, including the belief that it involves alterations in the visual cortex and impairments in the magnocellular and parvocellular cells in the lateral geniculate system of the thalamus, which is essential for reading and processing visual information related to movement. More recently, an fMRI study revealed functional differences between individuals with MISViS and control participants, specifically highlighting neuroanatomical variations. The study found that participants with MISViS exhibited distinct differences in impulse response function intensity in the Brodmann area 6 and parietal gyrus. Additionally, there were notable differences in the percentage of active voxels in regions including Brodmann areas 17 and 19, the parietal gyrus, and Brodmann area 6, indicating altered brain function associated with this condition. Further research will be needed to confirm these findings.

Diagnosis

Symptoms

Symptoms could include light-sensitivity, reading problems, discomfort, writing problems, depth perception, and visual distortions.

Individuals with this condition can experience significant physical discomfort and cognitive challenges during tasks involving visual processing, particularly reading. These difficulties can lead to broader behavioral adaptations, such as avoiding visually intensive tasks, becoming easily distracted, seeking out environments with less visual strain, and relying on alternative learning strategies, like favoring auditory over visual information processing. These challenges may result in coping mechanisms that can impact academic performance and daily activities.

Some studies suggest a possible association with other learning disabilities, such as attention deficit disorder (ADHD) and autism spectrum disorder (ASD).

Clinical diagnosis

A proposed diagnosis of MISViS includes a review of the history, a formal self-survey to identify symptoms, a screen by “certified Irlen providers” and improvement of symptoms with addition of the colored lenses. Unfortunately, there is no biomarker or imaging finding that can diagnose MISViS.

• The self-survey screening and diagnosis process that has been described includes the following:
  • Stage 1 Diagnostic Phase: initial screening with the Irlen Reading Perception Scale (IRPS). The IRPS determines severity of reading difficulties, visual discomfort and distortions, and improvement based on cover overlays.  
  • Stage 2 Treatment Phase: full assessment and determination of Irlen lens filter color combination for reduction of symptoms which demonstrates an immediate improvement, usually exceeding 5%, on the Wilkins Rate of Reading Test (WRRT).

Training for diagnosing can be completed via training courses.

Differential diagnosis

The symptoms of the MISViS overlap significantly with other identifiable vision anomalies, such as accommodative, binocular, and ocular motor dysfunctions. These other ocular motor conditions should be considered before establishing diagnosis, including dyslexia, ADHD, autism spectrum disorder, behavior problems, and psychological or psychiatric disorders.

Management

Treatment

MISViS reportedly responds to the use of colored (Irlen) lenses, as well as computerized accessibility options, like inverting colors and modifying background colors. The purported mechanism of Irlen lenses is to filter out specific wavelengths of light that are thought to be less well-tolerated by individuals with MISViS. However, a randomized controlled trial conducted on children who were previously diagnosed with MISViS by an Irlen specialist found that these lenses did not produce any significant improvement in reading ability.

In addition, other studies on the use of these specialized lenses for MISViS have been variable and inconsistent and unfortunately much of the existing evidence base suffers from problems and limitations in methodology, data analytics, and variability in protocol in the available trials. One systematic review of the available studies on MISViS showed high heterogeneity among studies, and lack of evidence on the existence of MISViS and treatment effectiveness.

Conclusion

Due to the debate about the efficacy of colored (Irlen) lenses for symptomatic patients with features of MISViS, the AAO recommends evaluation by an ophthalmologist with experience with pediatric care to exclude alternative etiologies. The discussion of MISViS should include a fair and objective discussion with the parents on the strengths and weaknesses of the available data and the status of the current recommendations. Other ocular motor pathology should be identified and treated if present.

It is unlikely that the controversy will be resolved without further study, but ophthalmologists should be aware of MISViS and be prepared to discuss the limitations of diagnosis and treatment on an individual basis with patients and their families.