Irlen syndrome | |
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Pseudomedical diagnosis | |
Risks | Nocebo |
Irlen syndrome (or scotopic sensitivity syndrome) is not a medical condition. It is a type of visual processing disorder which, research shows, can be mitigated through individualized spectral filtering. Some suggest the ideas of Irlen syndrome are pseudoscientific and not supported by scientific evidence, [1] [2] [3] and its treatment has been described as a health fraud taking advantage of vulnerable people; [4] however, more then 200 peer-reviewed published scientific articles support the existence of the condition and efficacy of spectral filtering as an intervention [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] .[ excessive citations ] Irlen syndrome is recognized by the US and Australian defense forces.
The condition was first identified in the 1980s. [23]
The Irlen method uses colored overlays and tinted lenses in the form of glasses or contact lenses. The method is intended to correct visual processing problems; brain imaging studies show improved brain function that correlates with reduced symptomology in associated with Irlen syndrome. [24] [13] [18]
In 1980, New Zealand teacher Olive Meares described the visual distortions some individuals reported when reading from white paper. In 1983, while working under a federal research grant at the California State University of Long Beach, American psychologist Helen Irlen thought that filtering the visual information before reaching the brain through the use of either colored overlays or spectral filters (worn as glasses), could allow the brain to correctly process the visual information it received. They thought that in doing so, these colored overlays and spectral filters could eliminate symptoms associated with Irlen syndrome. Similar symptoms were separately described by Meares and Irlen, each unaware of the other's work. Irlen, who was the first to systematically define the condition, named the condition "scotopic sensitivity syndrome," though in years following, some referred to it as Meares-Irlen syndrome, Irlen syndrome, and visual stress. [25]
Early studies investigating Irlen syndrome as a treatable condition have been criticized for having a biased and subjective approach to their research. [23]
Dyslexia, previously known as word blindness, is a learning disability that affects either reading or writing. Different people are affected to different degrees. Problems may include difficulties in spelling words, reading quickly, writing words, "sounding out" words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. The difficulties are involuntary, and people with this disorder have a normal desire to learn. People with dyslexia have higher rates of attention deficit hyperactivity disorder (ADHD), developmental language disorders, and difficulties with numbers.
The visible spectrum is the band of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light . The optical spectrum is sometimes considered to be the same as the visible spectrum, but some authors define the term more broadly, to include the ultraviolet and infrared parts of the electromagnetic spectrum as well, known collectively as optical radiation.
Achromatopsia, also known as rod monochromacy, is a medical syndrome that exhibits symptoms relating to five conditions, most notably monochromacy. Historically, the name referred to monochromacy in general, but now typically refers only to an autosomal recessive congenital color vision condition. The term is also used to describe cerebral achromatopsia, though monochromacy is usually the only common symptom. The conditions include: monochromatic color blindness, poor visual acuity, and day-blindness. The syndrome is also present in an incomplete form that exhibits milder symptoms, including residual color vision. Achromatopsia is estimated to affect 1 in 30,000 live births worldwide.
Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom, photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical sensitivity of the eyes, though the term is sometimes additionally applied to abnormal or irrational fear of light, such as heliophobia. The term photophobia comes from Greek φῶς (phōs) 'light' and φόβος (phóbos) 'fear'.
Amblyopia, also called lazy eye, is a disorder of sight in which the brain fails to fully process input from one eye and over time favors the other eye. It results in decreased vision in an eye that typically appears normal in other aspects. Amblyopia is the most common cause of decreased vision in a single eye among children and younger adults.
Visual snow syndrome (VSS) is an uncommon neurological condition in which the primary symptom is that affected individuals see persistent flickering white, black, transparent, or colored dots across the whole visual field.
Ocular dominance, sometimes called eye preference or eyedness, is the tendency to prefer visual input from one eye to the other. It is somewhat analogous to the laterality of right- or left-handedness; however, the side of the dominant eye and the dominant hand do not always match. This is because both hemispheres control both eyes, but each one takes charge of a different half of the field of vision, and therefore a different half of both retinas. There is thus no direct analogy between "handedness" and "eyedness" as lateral phenomena.
Computer vision syndrome (CVS) is a condition resulting from focusing the eyes on a computer or other display device for protracted, uninterrupted periods of time and the eye's muscles being unable to recover from the constant tension required to maintain focus on a close object.
In the study of visual perception, scotopic vision is the vision of the eye under low-light conditions. The term comes from the Greek skotos, meaning 'darkness', and -opia, meaning 'a condition of sight'. In the human eye, cone cells are nonfunctional in low visible light. Scotopic vision is produced exclusively through rod cells, which are most sensitive to wavelengths of around 498 nm and are insensitive to wavelengths longer than about 640 nm. Under scotopic conditions, light incident on the retina is not encoded in terms of the spectral power distribution. Higher visual perception occurs under scotopic vision as it does under photopic vision.
Vision therapy (VT), or behavioral optometry, is an umbrella term for alternative medicine treatments using eye exercises, based around the pseudoscientific claim that vision problems are the true underlying cause of learning difficulties, particularly in children. Vision therapy has not been shown to be effective using scientific studies, except for helping with convergence insufficiency. Most claims—for example that the therapy can address neurological, educational, and spatial difficulties—lack supporting evidence. Neither the American Academy of Pediatrics nor the American Academy of Ophthalmology support the use of vision therapy.
A reading disability is a condition in which a person displays difficulty reading. Examples of reading disabilities include developmental dyslexia and alexia.
A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits. Visual field testing can be performed clinically by keeping the subject's gaze fixed while presenting objects at various places within their visual field. Simple manual equipment can be used such as in the tangent screen test or the Amsler grid. When dedicated machinery is used it is called a perimeter.
In clinical diagnostic and functional development, special needs refers to individuals who require assistance for disabilities that may be medical, mental, or psychological. Guidelines for clinical diagnosis are given in both the Diagnostic and Statistical Manual of Mental Disorders and the International Classification of Diseases 9th edition. Special needs can range from people with autism, cerebral palsy, Down syndrome, dyslexia, dyscalculia, dyspraxia, dysgraphia, blindness, deafness, ADHD, and cystic fibrosis. They can also include cleft lips and missing limbs. The types of special needs vary in severity, and a student with a special need is classified as being a severe case when the student's IQ is between 20 and 35. These students typically need assistance in school, and have different services provided for them to succeed in a different setting.
Like Colour To The Blind (1996) is the third in a series of four autobiographical works by internationally bestselling autistic author Donna Williams.
Strephosymbolia was Samuel Orton's theory of dyslexia which he first published in 1925. The root strepho is Ancient Greek for "twisted" or "reversed" and he used this in preference to the phrase "word blindness", which he thought inaccurate as the difficulty was not that those with strephosymbolia could not see the words but that they had difficulty comprehending them. As he developed his theory, he attributed the difficulty to an imperfect dominance of the hemisphere of the brain which processed the symbols when reading, being confused by a residual but reversed equivalent in the other hemisphere.
The history of dyslexia research spans from the late 1800s to the present.
Dyslexia is a reading disorder wherein an individual experiences trouble with reading. Individuals with dyslexia have normal levels of intelligence but can exhibit difficulties with spelling, reading fluency, pronunciation, "sounding out" words, writing out words, and reading comprehension. The neurological nature and underlying causes of dyslexia are an active area of research. However, some experts believe that the distinction of dyslexia as a separate reading disorder and therefore recognized disability is a topic of some controversy.
Deaf and hard of hearing individuals with additional disabilities are referred to as "Deaf Plus" or "Deaf+". Deaf children with one or more co-occurring disabilities could also be referred to as hearing loss plus additional disabilities or Deafness and Diversity (D.A.D.). About 40–50% of deaf children experience one or more additional disabilities, with learning disabilities, intellectual disabilities, autism spectrum disorder (ASD), and visual impairments being the four most concomitant disabilities. Approximately 7–8% of deaf children have a learning disability. Deaf plus individuals utilize various language modalities to best fit their communication needs.
Color blind glasses or color correcting lenses are light filters, usually in the form of glasses or contact lenses, that attempt to alleviate color blindness, by bringing deficient color vision closer to normal color vision or to make certain color tasks easier to accomplish. Despite its viral status, the academic literature is generally skeptical of the efficacy of color correcting lenses.
[We] consider this method to be a classic example of a commercial enterprise preying on vulnerable and desperate individuals in search of simple solutions for developmental disorders and disabilities
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