A comparison of two-coloured filter systems for treating visual reading difficulties

Abstract

PurposeVisual disturbances that make it difficult to read text are often termed “visual stress”. Coloured filters in spectacles may help some children overcome reading problems that are often caused by visual stress. It has been suggested that for optimal effect each child requires an individually prescribed colour for each eye, as determined in systems such as the “Harris Foundation” coloured filters. Alternatively, it has been argued that only blue or yellow filters, as used in the “Dyslexia Research Trust” (DRT) filter system, are necessary to affect the underlying physiology.MethodA randomised, double blind trial with 73 delayed readers, was undertaken to compare changes in reading and spelling as well as irregular and non-word reading skills after 3 months of wearing either the Harris or the DRT filters.ResultsReading improved significantly after wearing either type of filter (t = −8.4, p < 0.01), with 40% of the children improving their reading age by 6 months or more during the 3 month trial. However, spelling ability (t = 2.1, p = 0.05) and non-word reading (f = 4.7, p < 0.05) improved significantly more with the DRT than with the Harris filters.ConclusionEducation and rehabilitation professionals should therefore, consider coloured filters as an effective intervention for delayed readers experiencing visual stress.Implications for RehabilitationAny disability that impacts on a child’s capacity to read has serious implications for academic development as well as the ability to participate independently in activities of daily living.One reading disability, generally termed “visual stress”, is related to visual disturbances that make it difficult to read text.This research demonstrates the beneficial use of coloured filters for promoting visual reading capacity for children with visual stress.Professionals who are involved in the needs of children with reading delay, may like to consider the benefits that coloured filters can afford children with visual reading problems.

Using coloured filters to reduce the symptoms of visual stress in children with reading delay

“…The authors cite one of their own publications in support of this (14). However, this study did not even contain a placebo control group.…”

Using coloured filters to reduce the symptoms of visual stress in children with reading delay

“…The BAS scoring system accounts for maturation as it is based on normalized data; this is recognized as a robust measure of reading ability. In addition the DRT filters, which had a more beneficial effect on visual stress symptoms, were also found to have had more effect on spelling ability and certain types of reading speed than those of participants using the Harris system (22).…”

“…It is interesting to note that the beneficial effects of the coloured filters on visual stress symptoms were mirrored by reading improvements, as measured by increases in BAS s scores, in a parallel study in the same children (22); after wearing either kind of filter for three months both the DRT and the Harris Foundation groups had improved their BAS s scores: for DRT by 1.8 and Harris by 1.7: equivalent to an average of 4.5 months over the three months, i.e. 1.5 months more than you would expect for an average child's progress.…”

“…Ethics approval was gained from Oxford Research Ethics Committee (01.02) by JS. The full study design has been reported elsewhere as the data were collected as part of a trial which examined the effect of the filter systems on reading and spelling ability (22). The effect of the two colour-filter systems on the symptoms of visual stress is reported here.…”

“…These two systems were selected as the Local Education Authority requested that two filter systems with relatively simple screening procedures were tested. It was felt ethically unjustified to use a control group in the design as no benefit had been achieved with placebo filters during independent trials of these types of filters (21,22). Ethics approval was gained from Oxford Research Ethics Committee (01.02) by JS.…”