Visual stress in adults with and without dyslexia

Abstract

The relationship between dyslexia and visual stress (sometimes known as MearesIrlen syndrome) is uncertain. While some theorists have hypothesised an aetiological link between the two conditions, mediated by the magnocellular visual system, at the present time the predominant theories of dyslexia and visual stress see them as distinct, unrelated conditions, a view that has received some support from studies with children. Studies of visual stress in adults are rare, yet recent reports of a high incidence of this phenomenon amongst university students with diagnosed dyslexia call for further investigation of the issue. This study sought to clarify the relationship between visual stress and dyslexia by comparing the reading performance of dyslexic and non-dyslexic adults with, and without, colour. Degree of susceptibility to visual stress was determined by means of a symptom rating scale. Optimal colour was determined using an Intuitive Colorimeter, which was also employed to assess reading speed under the two experimental conditions. Only the dyslexic students with high visual stress showed significant gains in reading speed when using optimal colour. The use of response to treatment (rather than symptomatology) as a diagnostic criterion for visual stress is questioned, especially when applied to adults, as this may give misleading findings. On the basis of reported symptomatology, students who experience high levels of visual stress are more likely to show improvements in reading rate with optimal colour if they also have dyslexia than if they do not have dyslexia. Although not establishing an aetiological link, these findings imply an interaction between the two conditions with major implications for theory, diagnosis and treatment.The view that visual factors are involved in dyslexia has a long and controversial history. The current predominant theory -which is so well supported that it could be said to have acquired the status of orthodoxy -is that dyslexia is caused by a genetically-based anomaly in neurological systems sub-serving phonological processing (see

The Effect of Colored Overlays on Reading Fluency in Individuals with Dyslexia

“…These results support the previous research demonstrating colored overlays have little effect on reading fluency (e.g., Ritchie et al 2011). Further, whereas previous research has suggested that colored overlays have greater effect on children with dyslexia than adults (Singleton and Trotter 2005;Singleton and Henderson 2007), this study suggests that colored overlays may have a deleterious effect on adults. Although colored overlays did not improve reading fluency for the children in this study, the adult's performance actually worsened with the colored overlay intervention.…”

“…Colored overlays are claimed to alleviate visual stress and improve symptoms commonly related to dyslexia such as low reading rate, accuracy, and comprehension (Evans et al 1999;Rickelman & Henk, 1990; BWhat is Irlen Syndrome,n .d.). This claim may be because visual stress often co-occurs with dyslexia (Singleton and Trotter 2005;Singleton and Henderson 2007). Colored overlays have become so common, they are now considered an approved accommodation for standardized tests in several states including California, New Mexico, Massachusetts, Nevada, and Oklahoma (BPublished Research,^n.d.,para.1).…”

Visual stress, its treatment with spectral filters, and its relationship to visually induced motion sickness

“…This statement is supported by both single masked clinical trials (Bouldoukian et al, 2002;Evans and Joseph, 2002;Kriss, 2002;Kriss andEvans, 2005, Singleton andHenderson, 2007;Singleton and Trotter, 2005;Swanson et al, 1993;Wilkins et al, 2001) and also by double-masked randomised placebo-controlled trials (Robinson and Foreman, 1999a, b;Wilkins et al, , 2002, in which filters of similar colour were offered as control. Additionally, a recent experiment studied reading speed at a large range of chromaticities and thereby directly addressed the issue of the precision with which the coloured filters need to be prescribed so as to suit an individual .…”

Effect of Colored Overlays on Reading Comfort in People with and without Meares-Irlen Syndrome

“…Indeed, a previous study has suggested that blue and bluish-green overlays (which exclude long-wavelength light) facilitate reading [30]; however, the most beneficial overlay color has been found to vary among individuals [5,8,22,23,31]. While the source of between-individual variation remains unclear [32], studies have investigated which colors are most beneficial to patients with MIS.…”