A Functional Neuroimaging Case Study of Meares-Irlen Syndrome/Visual Stress (MISViS).
Brain Topography [2012, 25(3):293-307]
The aim of this study is to evaluate the data from a participant in a reading study who had a diagnosis of Meares-Irlen syndrome/visual stress (MISViS). MISViS is characterised by visual distortions and somatic issues, which are remediated using coloured filters. The authors present a case study providing descriptive neurobiological comparisons of MISViS versus a control group. The study involved eleven English language speakers who participated in behavioural and neuroimaging versions of a language experiment with varied proportions of regular and exception words. Behavioural measures included accuracy and response times. Neuroimaging was conducted using a 1.5T Siemens Sonata MRI. The MISViS participant's data were removed from the overall experiment and analysed as a case study. Impulse response functions (IRFs) and percentage of active voxels were extracted from four regions of interest: BAs 17, 18, 19, and the postcentral gyrus (PG) and two control regions (BA6 and left BA45). The results indicated that significant differences existed between the control group and the MISViS participant for IRF intensity in two regions (BA6 and PG) and percentage of active voxels in four regions (BA17, BA19, PG, and BA6). No significant differences occurred in left BA45 for either variable of interest. No significant differences were found for behavioural measures. In conclusion, our findings offer one of the first neurobiological descriptions of differences in IRF intensity and percentage of active voxels in visual and somatosensory cortex during a language experiment for a participant with MISViS in the absence of migraine compared to controls. « Less
The aim of this study is to evaluate the data from a participant in a reading study who had... More »
Irlen colored overlays do not alleviate reading difficulties.
Della Sala S,
Pediatrics [2011, 128(4):e932-8]
OBJECTIVES: To test the efficacy of Irlen colored overlays for alleviating reading difficulties ostensibly caused by Irlen syndrome, a proposed perceptual disorder with controversial diagnostic status.
PARTICIPANTS AND METHODS: Sixty-one schoolchildren (aged 7-12 years) with reading difficulties were assessed by an Irlen diagnostician. We used a within-subject study design to examine differences in reading rate across 3 conditions: using an overlay of a prescribed color; using an overlay of a nonprescribed color; and using no overlay. In a subset of 44 children, all of whom had a diagnosis of Irlen syndrome, we also used a between-group design to test the effects of Irlen colored overlays on a global reading measure.
RESULTS: The Irlen diagnostician diagnosed Irlen syndrome in 77% of our poor readers. We found no evidence for any immediate benefit of Irlen colored overlays as measured by the reading-rate test or the global reading measure.
CONCLUSIONS: Our data suggest that Irlen colored overlays do not have any demonstrable immediate effect on reading in children with reading difficulties. « Less
OBJECTIVES: To test the efficacy of Irlen colored overlays for alleviating reading difficulties... More »
The role of attributional bias and visual stress on the improvement of reading speed using colored filters.
Perceptual and Motor Skills [2011, 112(3):770-82]
This study tested the predictions derived from two explanatory theoretical models of the effects of colored filters on reading speed: the theory of attributional bias and the theory of visual stress associated with reading. The experimental group consisted of 27 secondary school students (14 boys, 13 girls) diagnosed with the Meares-Irlen syndrome; the control group had 27 students paired in age and sex with the experimental group. The mean age of the sample was 12 years, 10 months (SD = 8.9 mo.). The effects of colored filters on reading speed and accuracy were tested using a word reading test and a visual stress induction text. The presentation method tapped individuals' visual sensitivity and response criteria. The results support some predictions of the theory of attributional bias, but more research is needed to assess each theory of reading speed. « Less
This study tested the predictions derived from two explanatory theoretical models of the effects... More »
Screening for dyslexia, dyspraxia and Meares-Irlen syndrome in higher education.
Dyslexia (Chichester, England) [2009, 15(1):42-60]
This study reports a comparison of screening tests for dyslexia, dyspraxia and Meares-Irlen (M-I) syndrome in a Higher Education setting, the University of Worcester. Using a sample of 74 volunteer students, we compared the current tutor-delivered battery of 15 subtests with a computerized test, the Lucid Adult Dyslexia Screening test (LADS), and both of these with data on assessment outcomes. The sensitivity of this tutor battery was higher than LADS in predicting dyslexia, dyspraxia or M-I syndrome (91% compared with 66%) and its specificity was lower (79% compared with 90%). Stepwise logistic regression on these tests was used to identify a better performing subset of tests, when combined with a change in practice for M-I syndrome screening. This syndrome itself proved to be a powerful discriminator for dyslexia and/or dyspraxia, and we therefore recommend it as the first stage in a two-stage screening process. The specificity and sensitivity of the new battery, the second part of which comprises LADS plus four of the original tutor delivered subtests, provided the best overall performance: 94% sensitivity and 92% specificity. We anticipate that the new two-part screening process would not take longer to complete. « Less
This study reports a comparison of screening tests for dyslexia, dyspraxia and Meares-Irlen... More »
Dyslexia: a review of two theories.
Clinical & Experimental Optometry : Journal of the Australian Optometrical Association [2008, 91(4):333-40]
Optometrists will frequently see patients, who may have a diagnosis or a suspected diagnosis of dyslexia (specific reading disorder) and will need to manage and counsel such patients. There are many propounded theories on the cause(s) of dyslexia. Although most professionals in this area consider that dyslexia is chiefly a linguistic disorder, the possibility of a visual component is contentious. This article is a selective review of two commonly discussed theories that suggest a visual component in dyslexia; the magnocellular deficit theory and Meares-Irlen syndrome. « Less
Optometrists will frequently see patients, who may have a diagnosis or a suspected diagnosis... More »
The Pattern Glare Test: a review and determination of normative values.
Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists) [2008, 28(4):295-309]
Pattern glare is characterised by symptoms of visual perceptual distortions and visual stress on viewing striped patterns. People with migraine or Meares-Irlen syndrome (visual stress) are especially prone to pattern glare. The literature on pattern glare is reviewed, and the goal of this study was to develop clinical norms for the Wilkins and Evans Pattern Glare Test. This comprises three test plates of square wave patterns of spatial frequency 0.5, 3 and 12 cycles per degree (cpd). Patients are shown the 0.5 cpd grating and the number of distortions that are reported in response to a list of questions is recorded. This is repeated for the other patterns. People who are prone to pattern glare experience visual perceptual distortions on viewing the 3 cpd grating, and pattern glare can be quantified as either the sum of distortions reported with the 3 cpd pattern or as the difference between the number of distortions with the 3 and 12 cpd gratings, the '3-12 cpd difference'. In study 1, 100 patients consulting an optometrist performed the Pattern Glare Test and the 95th percentile of responses was calculated as the limit of the normal range. The normal range for the number of distortions was found to be <4 on the 3 cpd grating and <2 for the 3-12 cpd difference. Pattern glare was similar in both genders but decreased with age. In study 2, 30 additional participants were given the test in the reverse of the usual testing order and were compared with a sub-group from study 1, matched for age and gender. Participants experienced more distortions with the 12 cpd grating if it was presented after the 3 cpd grating. However, the order did not influence the two key measures of pattern glare. In study 3, 30 further participants who reported a medical diagnosis of migraine were compared with a sub-group of the participants in study 1 who did not report migraine or frequent headaches, matched for age and gender. The migraine group reported more symptoms on viewing all gratings, particularly the 3 cpd grating. The only variable to be significantly different between the groups was the 3-12 cpd difference. In conclusion, people have an abnormal degree of pattern glare if they have a Pattern Glare Test score of >3 on the 3 cpd grating or a score of >1 on the 3-12 cpd difference. The literature suggests that these people are likely to have visual stress in everyday life and may therefore benefit from interventions designed to alleviate visual stress, such as precision tinted lenses. « Less
Pattern glare is characterised by symptoms of visual perceptual distortions and visual stress... More »
Meares-Irlen syndrome - a need for increasing awareness in the general public.
Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists) [2008, 28(3):291; author reply 291-2]
Visual processing characteristics of children with Meares-Irlen syndrome.
Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists) [2008, 28(1):35-46]
The potential role of visual processing deficits in reading difficulty was brought to public attention by claims that a large proportion of children with dyslexia suffer from a perceptual dysfunction currently referred to as Meares-Irlen syndrome (MISViS). A previous study showing that visual perceptual measures involving visual memory and discrimination predict independent variance in reading achievement [J. Learn. Disabil. 28 (1995) 216] provides a basis to examine their relationships with the diagnostic criteria of MISViS. This study examined these visual processing characteristics in 36 eight- to ten-year-old children, half of whom were experiencing reading difficulty. Children were assessed for MISViS by Irlen screeners; approximately half of the participants in each group were positively identified. Concurrent performance on standardized visual processing tests showed that while a positive diagnosis of MISViS is not indicative of reading ability, nor in particular of a visual-processing deficit subtype identified by Watson and Willows [J. Learn. Disabil. 28 (1995) 216], MISViS can indicate visual processing difficulties potentially related to visual attention inefficiency. « Less
The potential role of visual processing deficits in reading difficulty was brought to public... More »
Are orthoptic exercises an effective treatment for convergence and fusion deficiencies?
Strabismus [2006, 14(4):183-9]
PURPOSE: To investigate whether orthoptic exercises are an effective way to influence the near point of convergence, fusion range and asthenopic symptoms.
METHODS: Seventy-eight patients met the inclusion criteria of visual acuity 6/9 or better, no history of orthoptic treatment, squint surgery or Meares Irlen syndrome/dyslexia. Information was collected from case records related to diagnosis, near point of convergence, fusion range, prism and cover test measurements and symptoms. Type, duration and frequency of exercises were also recorded. Non-parametric statistics were applied.
RESULTS: Patients ranged in age from 5 to 73 years (mean 11.9). Females outnumbered males (46:32). The diagnoses were: decompensating heterophoria (n = 50) or convergence insufficiency (n = 28: primary 27; secondary 1). Exophoria was more common (n = 65), than esophoria (n = 11) or orthophoria (n = 1). Treatments were aimed at improving near point of convergence and/or reduced fusional reserves. The mean treatment period was 8.2 months. Reduced near point of convergence normalized following treatment in 47/55 cases, and mean near point of convergence improved from 16.6 to 8.4 cm (p = 0.0001). Fusional reserves normalized in 29/50. Fusional convergence improved significantly for those with exodeviation (p > 0.0006). Asthenopic symptoms improved in 65 patients. A reduction in deviation of 5 pd or more occurred in 20 patients.
CONCLUSIONS: Orthoptic exercises are an effective means of reducing symptoms in patients with convergence insufficiency and decompensating exophoria, and appear to target the proximal and fusional components of convergence. Their role in esophoria is unclear and needs further study. « Less
PURPOSE: To investigate whether orthoptic exercises are an effective way to influence the near... More »
Colour processing in autism spectrum disorders.
(Thesis:428989) Free resource
University of London 
The research described in this thesis investigated colour processing in children and adolescents with autism spectrum disorders. Although idiosyncratic responses to colour have been widely reported in autism (William, 1999; White & White, 1991), and therapeutic interventions involving colour are frequently used with individuals with this disorder (Howlin, 1996; Irlen, 1991), few controlled colour processing investigations have been carried out. The experiments reported in the thesis have two main points of focus. Firstly, the therapeutic effects of colour overlays on different aspects of cognition were tested, and secondly, studies into colour discrimination, memory, naming and categorisation were carried out in order to evaluate the role of language and perceptual processing in colour processing. In experiments one and two it was established that significantly more children with autism than age and intelligence matched controls improved their reading speed when using a colour overlay. In experiments three and four, these effects were further investigated using visual change detection and reading comprehension tasks with and without colour overlays. Again, a significant improvement in performance was noted in the autism group when using colour overlays. The results from experiments four to eleven, testing colour discrimination, memory and naming failed to confirm atypical colour processing in autism, although the findings did suggest that cognitively unimpaired children with autism showed sharper category boundaries than those with autism and cognitive impairment and typically developing controls. Finally data from a case study of a boy with Asperger Syndrome who showed highly idiosyncratic colour responses were presented. The findings from the studies are discussed within the context of current theories of visual cognition in autism and theories of colour perception. « Less
The research described in this thesis investigated colour processing in children and adolescents... More »
The need for optometric investigation in suspected Meares-Irlen syndrome or visual stress.
Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists) [2005, 25(4):363-70]
Meares-Irlen syndrome is characterised by symptoms of eye strain, headaches and visual perceptual distortions when viewing text. The symptoms are alleviated with individually prescribed coloured filters, such as precision tinted lenses. Meares-Irlen syndrome, and the related condition of visual stress, are likely to result from hyperexcitability of the visual cortex, which can also occur in migraine. The symptoms of Meares-Irlen syndrome and visual stress are non-specific and the condition needs to be differentially diagnosed from other optometric conditions, such as refractive error, binocular vision anomalies, and accommodative anomalies. Three case reports are described of patients who consulted the author with suspected Meares-Irlen syndrome but were found to have other causes for their symptoms: posterior sub-capsular cataract, high uncorrected astigmatism, and decompensated convergence weakness exophoria. These cases highlight the need for professional eye care for people with suspected Meares-Irlen syndrome. Although this advice is stressed in literature on the well-established MRC/Wilkins Intuitive Colorimeter system, it is not always stressed in literature about other systems. This may be a cause for concern. « Less
Meares-Irlen syndrome is characterised by symptoms of eye strain, headaches and visual perceptual... More »
Plasma cholesterol levels and Irlen syndrome: preliminary study of 10- to 17-yr.-old students.
Perceptual and Motor Skills [2003, 97(3 Pt 1):743-52]
The preliminary study investigated metabolic anomalies in children and teenagers with Irlen Syndrome, particularly in relation to the levels of n-3 and n-6 essential fatty acids, plasma cholesterol levels, and the relative abundance of plasma saturated fatty acids. The experimental group involved 13 subjects with Irlen Syndrome (M=13.3 yr., SD=2.5 yr.), with a comparison group of 16 age- and sex-matched controls (M=13.8 yr., SD=2.4 yr.). The Irlen Syndrome group were selected from people referred for help with reading and writing problems. The control group were primarily recruited from the general public. All subjects were screened for symptoms of the syndrome using the Scotopic Sensitivity Syndrome Screening Manual. Samples of whole blood were collected and plasma extracted. Metabolites were compared using the Student t test. There were no differences in n-3 and n-6 essential fatty acids between Irlen Syndrome and control groups, although the former group had lower mean levels in most of these essential fatty acids. Total plasma cholesterol level was significantly decreased for the Irlen Syndrome group, and there was a significant increase in the relative abundance of the odd-chain fatty acid, heptadecanoic acid. The differences in heptadecanoic acid may have implications for altered membrane function and neurotransmission. The differences in plasma cholesterol levels, as well as heptadecanoic acid, may also point to the presence of viral or bacterial infection. « Less
The preliminary study investigated metabolic anomalies in children and teenagers with Irlen... More »
The Irlen syndrome--are there pathophysiologic correlates and scientific evidence for "reading with colors"?
Zeitschrift fur Kinder- und Jugendpsychiatrie und Psychotherapie [2003, 31(4):305-9]
Psychophysical and ocular motor aspects of visual processing in dyslexics with Meares Irlen Syndrome.
(Thesis:404683) Free resource
Glasgow Caledonian University 
The effect of coloured filters on the rate of reading in an adult student population.
Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists) [2002, 22(6):535-45]
Meares-Irlen Syndrome is characterised by visual stress (visual discomfort) and visual perceptual distortions that can be alleviated by individually prescribed coloured filters. The benefit from coloured filters can be demonstrated with the Wilkins Rate of Reading Test (WRRT). Previous research using individually prescribed coloured overlays (sheets of plastic placed on a page) found that between one-fifth and one-third of unselected school-children show a significant (> 5%) improvement in their rate of reading with their chosen overlay. This 5% cut-off has good sensitivity and specificity for predicting those children who will continue to voluntarily use their overlay for a sustained period. Previous research has concentrated on children, and we sought to investigate the immediate effect of overlays on rate of reading in an adult population. Subjects were 113 unselected university students who answered a symptom questionnaire and were tested with the Wilkins Intuitive Overlays and WRRT. Some symptoms were common: 73% reported sore or tired eyes when reading and 40% reported four to 12 headaches a year. One hundred of the subjects chose an overlay as improving their immediate perception of text. These subjects were significantly more likely to report perceptual distortions and visual discomfort on viewing text than subjects who did not choose an overlay. The 100 subjects read 3.8% faster with the overlay than without any overlay (p < 0.00001), whereas the 13 subjects who did not choose an overlay read 1.7% slower with a placebo overlay than without (p = 0.37). Of the subjects who chose an overlay, 38% read more than 5% faster with the overlay and 2% read more than 25% faster. These results are comparable with those obtained for children. We conclude that Meares-Irlen Syndrome is likely to be as common in adults as it is in children. « Less
Meares-Irlen Syndrome is characterised by visual stress (visual discomfort) and visual perceptual... More »
A biochemical analysis of people with chronic fatigue who have Irlen Syndrome: speculation concerning immune system dysfunction.
Perceptual and Motor Skills [2001, 93(2):486-504]
This study investigated the biological basis of visual processing disabilities in adults with Chronic Fatigue Syndrome. The study involved 61 adults with symptoms of Chronic Fatigue Syndrome who were screened for visual processing problems (Irlen Syndrome) and divided into two groups according to the severity of symptoms of Irlen Syndrome. Significant variations were identified in blood lipids and urine amino and organic acids of the two groups, which may be indicative of activation of the immune system due to some infective agent. It was suggested that metabolic profiling may help the development of more valid diagnostic categories and allow more investigation of immune system dysfunction as a possible causal factor in a range of learning and behaviour disorders. « Less
This study investigated the biological basis of visual processing disabilities in adults with... More »
Spatiotemporal visual function in tinted lens wearers.
Investigative Ophthalmology & Visual Science [2001, 42(3):879-84]
PURPOSE: Tinted lenses have been widely publicized as a successful new treatment for reading disorders and visual stress in children. The present study was designed to investigate a variety of visual deficits reported by children who experience high levels of visual stress and perceptual distortions when reading (Meares-Irlen syndrome; MIS) and to assess the improvements in visual comfort they report when tinted lenses are worn.
METHODS: Twenty children (13.1 +/- 0.9 years of age) were recruited who had successfully worn tinted lenses for at least 6 months and were compared with an age-matched control group (12.6 +/- 2.2 years of age) of 21 children who were not lens wearers. A range of psychophysical tasks was adapted to identify specific anomalous visual perceptions. Spatiotemporal contrast sensitivity and contrast increment thresholds were used to investigate subjective reports of dazzle and hypercontrast, and a minimum motion perception (D(min)) and a motion-coherence task were used to assess subjective reports of visual instability and motion.
RESULTS: In all viewing conditions (with versus without lens), no selective functional visual loss was demonstrated with any of the tasks used. Psychometric functions also revealed no significant difference between subject groups (control versus MIS).
CONCLUSIONS: Under thorough psychophysical investigation, these results revealed no significant difference in visual function between subject group, and this finding is consistent with the absence of any effect of the tinted lenses in the group with MIS. « Less
PURPOSE: Tinted lenses have been widely publicized as a successful new treatment for reading... More »
The familial incidence of symptoms of scotopic sensitivity/Irlen syndrome: comparison of referred and mass-screened groups.
Perceptual and Motor Skills [2000, 91(3 Pt 1):707-24]
The familial incidence of Scotopic Sensitivity/Irlen Syndrome was investigated in two samples. One sample involved parents and siblings of 126 children identified with symptoms who had been referred for screening. The other sample involved parents and siblings of 33 children who had been identified with symptoms through mass screening of all children in Grades 3 to 6 at two local schools. Two different samples were taken to investigate the possibility of parental referral bias. Familial incidence may be inflated in a referred sample because some parents may be aware of their own symptoms and actively seek assistance. For the sample of children referred for screening, there was an 81% chance of either one or both parents showing similar symptoms and a 76% chance of siblings being similarly affected. For the sample of children identified through school screening, there was an 85%, chance of either one or both parents showing similar symptoms and a 54% chance of siblings being similarly affected. The data confirm previous estimates of incidence and suggest that Scotopic Sensitivity/Irlen Syndrome may be a genetically-based deficit in visual processing. « Less
The familial incidence of Scotopic Sensitivity/Irlen Syndrome was investigated in two samples... More »
A review of the management of 323 consecutive patients seen in a specific learning difficulties clinic.
Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists) [1999, 19(6):454-66]
Visual correlates of specific learning difficulties (SpLD) include: binocular instability, low amplitude of accommodation, and Meares-Irlen Syndrome. Meares-Irlen Syndrome describes asthenopia and perceptual distortions which are alleviated by using individually prescribed coloured filters. Data from 323 consecutive patients seen over a 15 month period in an optometric clinic specialising in SpLD are reviewed. Visual symptoms and headaches were common. 48% of patients were given a conventional optometric intervention (spectacles, orthoptic exercises) and 50% were issued with coloured filters, usually for a trial period. 40% of those who were given orthoptic exercises were later issued with coloured overlays. 32% of those who were issued with coloured overlays were ultimately prescribed Precision Tinted lenses. Approximately half the sample were telephoned more than a year after the last clinical appointment. More than 70% of those who were prescribed Precision Tints were still wearing them daily, and results for this intervention compared favourably with data for non-tinted spectacles. The data suggest that many people with SpLD need optometric care and that the optometrist needs to be skilled in orthoptic techniques and cognisant of recent research on coloured filters. « Less
Visual correlates of specific learning difficulties (SpLD) include: binocular instability,... More »
Scotopic sensitivity/Irlen syndrome and the use of coloured filters: a long-term placebo controlled and masked study of reading achievement and perception of ability.
Perceptual and Motor Skills [1999, 89(1):83-113]
This study investigated the effects of using coloured filters on reading speed, accuracy, and comprehension as well as on perception of academic ability. A double-masked, placebo-controlled crossover design was used, with subjects being assessed over a period of 20 mo. There were three treatment groups (Placebo filters, Blue filters, and Optimal filters) involving 113 subjects with "reading difficulties", ranging in age from 9.2 yr. to 13.1 yr. and with an average discrepancy between chronological age and reading age of 1.8 yr. The 35 controls (who did not use coloured filters) ranged in age from 9.4 yr. to 12.9 yr., with an average discrepancy between chronological age and reading age of 2.1 yr. The treatment groups increased at a significantly greater rate than the control group in reading accuracy and reading comprehension but not for speed of reading. For self-reported perception of academic ability, two of the three treatment groups showed significantly greater increases than the control group. The larger improvements for treatment groups in reading comprehension may be related to a reduction in print and background distortions allowing attention to be directed to the processing of continuous text rather than to the identification of individual words. A reduction in print distortion, however, may not be sufficient to generate improved word-identification skills without additional remedial support, and this may be indicated by the nonsignificant increase in rate of reading. « Less
This study investigated the effects of using coloured filters on reading speed, accuracy, and... More »
Scotopic sensitivity/Irlen syndrome and the use of coloured filters: a long-term placebo-controlled study of reading strategies using analysis of miscue.
Perceptual and Motor Skills [1999, 88(1):35-52]
This study investigated the long-term effects of using coloured filters on the frequency and type of errors in oral reading. A double-masked, placebo-controlled crossover experimental design was used, with subjects being assessed over a period of 20 months. There were three experimental groups (Placebo tints, Blue tints, and Diagnosed tints) involving 113 subjects with reading difficulties, ranging in age from 9.2 yr. to 13.1 yr. The 35 controls (ranging in age from 9.4 yr. to 12.9 yr.) had reading difficulties but did not require coloured filters. There was a significant improvement for all groups in the accuracy of miscues over the period, although experimental groups over-all did not improve at a significantly different rate than the control group. The failure to find significantly greater improvement for the experimental groups over the control group for the total period, despite subjects' reports of improved print clarity, may be partly related to the lack of effective letter-sound analysis and synthesis skills and to the use of a word-identification strategy of guessing based on partial visual analysis. « Less
This study investigated the long-term effects of using coloured filters on the frequency and... More »
Visual perceptual difficulties and reading behaviour : Irlen syndrome and eye colour.
(Thesis:266995) Free resource
University of Bristol 
The familial incidence of symptoms of Scotopic Sensitivity/Irlen syndrome.
Perceptual and Motor Skills [1996, 83(3 Pt 1):1043-55]
The familial incidence of Scotopic Sensitivity/Irlen Syndrome was investigated using parents of 751 children identified with symptoms. Children were identified by methods independent of their parents' symptoms or lack of symptoms. For these children, there was an 84% chance of either one or both parents showing similar symptoms, with similar numbers of mothers identified with symptoms as fathers. The data suggest that Scotopic Sensitivity/Irlen Syndrome may be a genetically based deficit in visual processing, but the simplest genetic models do not appear to fit. « Less
The familial incidence of Scotopic Sensitivity/Irlen Syndrome was investigated using parents... More »
A preliminary investigation into the aetiology of Meares-Irlen syndrome.
Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists) [1996, 16(4):286-96]
A recent double-masked placebo-controlled trial has confirmed that some children experience a reduction in symptoms of eyestrain and headache when they read through individually prescribed coloured filters and has shown that this benefit cannot be solely attributed to a placebo effect. People who are helped by coloured filters in this way have been described as having "Meares-Irlen syndrome'. We investigated the mechanism of this benefit by studying the optometric and visual perceptual characteristics of the children in the double-masked study. This population had normal refractive errors and heterophorias (none of the subjects had strabismus). They demonstrated slightly, but significantly, reduced amplitudes of accommodation and vergence and poor stereo-acuity. However, these factors seemed to be correlates of Meares-Irlen syndrome rather than the underlying cause. Pattern glare, a sensitivity to striped patterns (e.g. lines of text), was prevalent in our sample and was significantly associated with the subjects' symptoms. The spatial contrast sensitivity function was normal. « Less
A recent double-masked placebo-controlled trial has confirmed that some children experience... More »
Optometric correlates of Meares-Irlen syndrome: a matched group study.
Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists) [1995, 15(5):481-7]
People who report visual perceptual distortions, typically when reading, that are alleviated by using coloured filters are described as suffering from 'Meares-Irlen Syndrome'. A recent double-masked placebo-controlled trial showed that this condition cannot be solely explained as a placebo effect and that the beneficial filter is idiosyncratic and sometimes needs to be highly specific. Several mechanisms have been suggested for Meares-Irlen Syndrome including ocular motor (binocular and accommodative) anomalies, a sensitivity to patterned stimuli (pattern glare), and a deficit of the transient visual sub-system. We investigated these hypotheses by comparing 16 children, who reported the symptoms described above and who showed a sustained benefit from coloured filters, with 25 control children who came from the same school and were matched for age, reading performance and intelligence. The 'Meares-Irlen Syndrome' group had slightly, but significantly, reduced vergence and accommodative amplitudes and stereo-acuity; they also demonstrated significantly more pattern glare. The two groups did not differ significantly in their visual acuities, refractive error, dissociated or associated heterophoria, AC/A ratio, or ability to perceive 20 Hz flicker. It appears that certain ocular motor factors are correlates of Meares-Irlen Syndrome, rather than the primary underlying cause of the symptoms. The results support the hypothesis that pattern glare may be involved in the mechanism of Meares-Irlen Syndrome. « Less
People who report visual perceptual distortions, typically when reading, that are alleviated... More »
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Use of filters to treat visual-perception problem creates adherents and sceptics.
(PMID:7882238) Free resource
CMAJ : Canadian Medical Association Journal = Journal de L'Association Medicale Canadienne [1995, 152(5):749-50]
Patients who think they have a visual-perception dysfunction known as scotopic sensitivity-Irlen syndrome have trouble reading and may experience almost-constant headaches. Some find they are helped by coloured filters developed by a California researcher, Helen Irlen, who published a book on the subject called Reading by the Colors. Although Irlen has been criticized for not publishing scientific proof of the validity of her theories, her techniques have found some support, including some within the medical community. « Less
Patients who think they have a visual-perception dysfunction known as scotopic sensitivity-Irlen... More »
Comparison of Irlen scotopic sensitivity syndrome test results to academic and visual performance data.
Journal of the American Optometric Association [1994, 65(10):705-14]
Irlen has defined a condition called Scotopic Sensitivity Syndrome (SSS) that is associated with reading problems. According to Irlen, SSS can be treated by the use of colored filters, but there is disagreement about the existence of SSS and the efficacy of colored filter therapy. METHODS: Thirty-nine children participated in the study: 24 were academically normal, nine had specific reading problems, and six had problems in multiple academic areas. SSS levels and preferred overlay colors were determined. Optometric test data were also available for each subject.
RESULTS: No significant relationships were found between academic classification and degree of SSS. There were also no significant relationships between preferred overlay color and any other variables. There was, however, a significant tendency for subjects with higher SSS levels to be candidates for vision therapy and to derive greater benefit from the colored overlays.
CONCLUSIONS: Many questions about the use of colored filters for the treatment of reading problems remain unanswered. Among these are questions dealing with whether the M-pathway anomalies found in some dyslexics are also present to a lesser degree in other cases of reading disabilities, and how colored filters could re-balance the M- and P-pathways. Is it the color of the filter itself that is critical, or is it the change in luminance or contrast produced by the filter that seems to make it easier for some subjects to read? More research will be needed to answer these questions. « Less
Irlen has defined a condition called Scotopic Sensitivity Syndrome (SSS) that is associated... More »
Effect of pattern glare and colored overlays on a stimulated-reading task in dyslexics and normal readers.
Optometry and Vision Science : Official Publication of the American Academy of Optometry [1994, 71(10):619-28]
Scotopic sensitivity syndrome or the Irlen syndrome describes symptoms of asthenopia anamolous visual performance experienced while reading that are lessened by colored filters. One putative explantation for this condition relates to pattern glare: a hypersensitivity to repetitive patterns, including lines of print on a page. Experiment 1 used a placebo-controlled paradigm to investigate the effect of pattern glare and colored overlays on performance at a simulated reading visual search task. Despite the fact that the subjects were university students, the results showed a tendency, of border-line significance, to support the conclusion that colored filters seem to improve reading through ameliorating pattern glare. In experiment 2 we compared the prevalence of pattern glare in matched groups of dyslexic children and good readers. The dyslexic group reported more pattern glare, but also reported more glare from a control stimulus. Pattern glare in the dyslexic group was directly correlated with flicker sensitivity. The results are related to recent research on visual processing and ocular-motor function in dyslexia. « Less
Scotopic sensitivity syndrome or the Irlen syndrome describes symptoms of asthenopia anamolous... More »
Dark adaptation in disabled readers screened for Scotopic Sensitivity Syndrome.
Perceptual and Motor Skills [1994, 78(1):131-41]
A peripheral retina, photoreceptor, or transient visual-system deficit has been suggested as a basis for dyslexia. We performed dark adaptation using a Goldmann-Weekers adaptometer on 41 dyslexic readers subjected to the Irlen Differential Perceptual Schedule for the Scotopic Sensitivity Syndrome and on 23 volunteers of normal reading ability, all aged between 10 and 20 years. 12 of the 41 disabled readers examined had abnormally poor dark adaptation at peripheral retinal locations consistent with a rod processing-system deficit. « Less
A peripheral retina, photoreceptor, or transient visual-system deficit has been suggested as... More »
A model of visual discomfort and its implications for efficient reading performance.
(Thesis:406) Free resource
University of Wollongong 
Visual discomfort has been described as an extreme sensitivity to bright or intermittent light and some forms of repetitive pattern stimuli. This sensitivity can result in physical symptoms of eye-strain and headache and induction of anomalous perceptual features with exposure to pattern (Wilkins et al., 1984). The pattern percept produced by the lines of print on a page of text has been likened to the pattern of anomalous stripes which can induce unpleasant effects in sensitive individuals (Wilkins & Nimmo-Smith, 1987). This sensitivity is increased in observers who report regular headache or those who report eye-strain and headache when reading.Scotopic Sensitivity Syndrome was a term coined by Men (1983) to describe a symptom complex which described anomalous physical, perceptual and performance difficulties reported when reading. This symptom complex is characterised by experience of photophobia, eye-strain difficulties, difficulties with depth perception and experience of anomalous perceptual difficulty with exposure to the print on a page of text (Irlen, 1983). As a result of these difficulties severe reading difficulty has been reported.In this work a model of visual discomfort was developed which combined the reports of physical and perceptual difficulties induced from observation of high contrast square-wave repetitive spatial patterns and a page of text (Wilkins et al., 1984; Wilkins & Nimmo-Smith, 1984; 1987) and the performance difficulties reported by Irlen (1983) to occur when reading. A unidimensional model of visual discomfort was developed using a rating scale version of the Rasch model in which person and item parameters were combined on a simple logistic scale. From this model it was predicted that as the number of positive responses to items on the visual discomfort scale increased the probability of experiencing more severe visual discomfort increased. This increasing difficulty would be revealed by a greater number of reports of unpleasant physical side-effects and anomalous perceptual distortion from repetitive spatial patterns. Performance difficulty if present would be reflected in reduced task efficiency.The similarities between this model and Wilkins (1986a) conceptualisation of visual discomfort was tested with investigation of reports of unpleasant physical side-effects and perceptual distortion from observation of square-wave gratings of intermediate spatial frequency and a page of text. It was found that higher scorers on the visual discomfort scale reported significantly more unpleasant physical side-effects and perceptual distortions from all the pattern types presented than low scorers on the scale. Further analysis demonstrated that high headache susceptibility observers also obtained higher scores on the visual discomfort scale, and reported a significantly greater number of unpleasant physical side-effects from observation of the high contrast square-waves than low headache susceptibility observers. Reports of... « Less
Visual discomfort has been described as an extreme sensitivity to bright or intermittent light... More »
Irlen lenses: a critical appraisal.
Solan HA, Richman J
Journal of the American Optometric Association [1990, 61(10):789-96]
The purpose of this paper is to assess the credibility of the Irlen lenses, Irlen's hypotheses, and the scotopic sensitivity syndrome. The analysis includes a review of 13 pro and con research papers. Of special interest is the dichotomy which developed between researchers who were Irlen participants and the professional and scientific community who required less disputable evidence. Even the former, however, failed to find scientific support for Irlen's concept of dysfunction in the discharge rate of the retinal receptor cells. Furthermore, in the absence of any evidence that it is a separate and distinct entity, it appears that the scotopic sensitivity syndrome is, in fact, a symptom complex which results primarily from various refractive, binocular, and accommodative disorders. Some of the papers which support Irlen's hypotheses provide reason to believe that there is a strong placebo effect. « Less
The purpose of this paper is to assess the credibility of the Irlen lenses, Irlen's hypotheses,... More »
Method and apparatus of treatment of symptoms of the Irlen syndrom
(Patent:US4961640) Free resource
IRLEN HELEN L
Specially tinted lenses will provide substantial benefits to patients with various forms of visual disturbance caused by a recently identified functional disorder called the Irlen Syndrome of scotopic sensitivity, who show over-stimulation of receptor cells in the wavelength band of 425 to 575 nm. Symptomatically, the Irlen Syndrome is characterized by reduced visual resolution, impaired depth perception, impaired peripheral vision, and ocular vertigo. With use of the lenses the patients report improved visual resolution, increased comfort from reduced symptoms of eye strain, increased depth perception and peripheral vision, and reduced symptoms of ocular vertigo. The treatment includes experientially fitting the patient with lenses of an optimal color and transmission density, namely a predetermined attenuation in the 425-575 nm band. It has been determined according to the invention that pink and peach singly or in combination with blue, green, gray, purple, goldenrod, and yellow tints, can be effectively combined to achieve symptomatic relief. The color and density which is optimal for each patient must be determined individually for each patient and optimized as evaluated by pre-testing and post-testing on the Irlen Differential Perception Scale. Tinting and optical density are further optimized in each patient for near vision, far vision, and night vision. « Less
Specially tinted lenses will provide substantial benefits to patients with various forms of... More »
Vision characteristics of individuals identified as Irlen Filter candidates.
Scheiman M, Blaskey P,
Journal of the American Optometric Association [1990, 61(8):600-5]
Individuals with "scotopic sensitivity syndrome" have been reported to have visual symptoms including eye strain, headaches, blurred vision, double vision and words moving on the page. This study was designed to investigate Irlen's claims that these symptoms are unrelated to vision anomalies. She suggests that the use of Irlen tinted lenses/filters relieves these symptoms and results in improved reading performance. Thirty nine subjects (age 10-49) were recruited by advertising for a study of Irlen Filters/Lenses. Before the Irlen screening all subjects received an optometric examination. The results of this study demonstrate that 95 percent of the subjects identified as candidates for Irlen Filters did have significant and readily identifiable vision anomalies. Fifty seven percent of the subjects had received vision care within the past year, yet testing revealed that 90 percent of these subjects had significant vision problems that had not been corrected. « Less
Individuals with "scotopic sensitivity syndrome" have been reported to have visual symptoms... More »
A review of the use of Irlen (tinted) lenses.
Australian and New Zealand Journal of Ophthalmology [1990, 18(3):307-12]
Helen Irlen identified a syndrome defined as 'scotopic sensitivity' which it was claimed could be responsible for the inability of some people to read fluently and the symptoms of which could be ameliorated by the wearing of prescribed coloured lenses. The literature to date presents a confused and inconsistent picture concerning the use of the lenses. The literature (much of which is unpublished and difficult to obtain) is critically reviewed. Recent experimental evaluations of the lenses do not support the use of the lenses as a useful intervention for children with reading disabilities. « Less
Helen Irlen identified a syndrome defined as 'scotopic sensitivity' which it was claimed could... More »
Reading with colours ... Irlen lenses and the treatment of scotopic sensitivity syndrome.
Davies M, Caritas [1989, 55(71):3-4]
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