Irlen syndrome

Disease Description (Causes and Symptoms)

• Confirming the disease name: The term "Irlen syndrome (얼렌 증후군)" is widely used in clinical practice, and synonyms include scotopic sensitivity syndrome, visual overload syndrome, and visual perceptual stress syndrome. However, this diagnostic name is a concept used by some experts and clinicians, and controversy exists because its definition and classification are not consistent throughout the medical community (reported prevalence and treatment effectiveness vary among studies).
• Proposed causes/pathophysiology: Some reports have proposed that abnormalities in the magnocellular system of the cerebral thalamic region or hypersensitivity to specific wavelengths of light are regularly associated with visual stress. The hypothesis has been proposed that, as a result, incoming visual information may overlap or become distorted, causing difficulties with reading and concentration.
• Reported clinical symptoms (main symptoms)
  • Skipping lines or repeatedly reading the same line while reading a book; omitting words
  • Reduced reading speed; reluctance to read long texts
  • Reduced comprehension and loss of attention after reading
  • Difficulty reading for long periods, eye strain, eye redness, headaches, drowsiness, and neck and shoulder tension
  • Difficulty reading under fluorescent lights or bright light (light sensitivity); feeling more comfortable in dark places
  • Visual perceptual distortions in which letters become blurred, appear double, or seem to move
  • Standard ophthalmologic examinations often show no abnormal findings
• Prevalence (reported): Although it varies greatly among studies, some reports have found a prevalence of approximately 10–14% in the general population, with higher rates reported among groups with dyslexia or accompanying attention problems (there is considerable variation among studies).

Treatment Methods and Precautions

• Tests before diagnosis
  • First, undergo a basic ophthalmologic evaluation at an ophthalmology department (or pediatric ophthalmology/visual function specialist), including visual acuity, refraction, strabismus, refractive error, and binocular coordination (convergence) tests, to identify and correct stable visual function problems such as refractive errors, amblyopia, and strabismus.
  • If necessary, neuropsychological testing (reading, perception, and attention assessments) or educational evaluation (dyslexia assessment) may be conducted concurrently.
  • Irlen screening (overlay/colored filter testing) is used as an adjunctive test to assess subjective symptom improvement.
• Treatment options
  • Colored filters (overlays) and special lenses (Irlen lenses): Some patients have reported improvements in subjective symptoms, such as reading comfort and headaches, but randomized controlled studies are limited and results are not consistent. The decision to use them should take cost and expected benefits into account.
  • Standard ophthalmologic treatment: If visual function abnormalities are identified, priority should be given to treatments such as refractive correction, prisms, or visual function (binocular coordination) therapy.
  • Educational, psychological, and rehabilitative approaches: Reading training, educational interventions (reading assistive technology), occupational therapy, and, when necessary, medication and behavioral therapy for ADHD and learning disabilities may be used concurrently.
  • Environmental assistance: Adjusting lighting, improving contrast (changing text size and font), using colored paper and non-glare surfaces, and following regular rest periods.
• Precautions
  • It cannot be guaranteed that colored filters alone will resolve all symptoms. Underlying ophthalmologic diseases, learning disabilities, and attention disorders should also be evaluated and treated.
  • When choosing commercial or nonstandardized tests or treatments, consider objective evidence, cost, and side effects.
  • If symptoms are severe or accompanied by headaches, visual field abnormalities, or reduced vision, neurological and ophthalmologic reevaluation is necessary.
• Complications and prognosis
  • Although directly life-threatening complications are rare, untreated symptoms may lead to reduced academic or work performance, stress, and reduced self-esteem.
  • Some people experience subjective improvement with colored filters, but long-term effects and whether learning ability improves depend on the underlying cause of the condition, such as dyslexia or ADHD.

Outpatient Visit Checkpoints (Examples of Items to Bring and Records to Keep)

• Items/documents to bring
  • The eyeglasses or contact lenses currently being used (if applicable)
  • Results of a recent ophthalmologic or vision examination (preferably from within the past year)
  • School report cards and learning assessment reports; diagnostic certificates related to dyslexia or ADHD (if applicable)
  • A list of medications currently being taken (name, dosage, and time taken)
  • Symptom diary: when symptoms began, triggers (light, screens, specific paper colors, etc.), duration, and conditions that worsen or improve symptoms
  • Photos taken when symptoms occur (e.g., a photo of a book under lighting with severe glare) or videos (which may be helpful if the letter distortion can be reproduced)
• Examples of questions to record in advance for the outpatient visit
  • When did the symptoms begin? Were they related to a specific event?
  • In what environments do the symptoms mainly occur (lighting, screens, printed material colors, etc.)?
  • How long do the symptoms last when they occur? What measures relieve them?
  • What specific difficulties occur at school or work (reading time, frequency of mistakes, etc.)?

Examples of General Questions to Ask the Doctor

• What other possible causes could be responsible for these symptoms?
• Which specialties should be involved in the evaluation: ophthalmology, neurology, or education (learning)?
• What is the basis for recommending colored filters (or Irlen lenses)? How will their effectiveness be assessed?
• If medication or visual function therapy is needed, what treatment do you recommend? What are the side effects?
• What nonmedication measures can I try immediately in my daily environment?

Examples of Personalized Questions by Disease

• In this patient's (my) case, how likely is it that using colored filters will improve the symptoms, and how should this be documented and assessed if the improvement is objectively confirmed?
• Since dyslexia or ADHD may be possible, do you recommend additional relevant testing (neuropsychological testing, reading assessment, or ADHD evaluation)? If so, which test would you recommend first?