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Visual stress resource centre Reading with visual stress


"This study showed that all but four children experienced improvements in both the reported clarity of the text and in the speed of their reading using either type of coloured reading aid..."

Reading is one of the most important skills for young children to acquire. Reading has an impact on basic skills in the general learning process, such as counting, writing, comprehending and phrasing. It is essential in all interactions in the classroom, in the school and in other environments.  Unfortunately, reading difficulties are common amongst primary school-aged children. Those who suffer from them from the beginning often do not catch up with the curriculum later. It is, therefore important to create awareness of any possible and easily applicable methods that can be used to help young children to improve their reading skills.

Visual Stress symptoms

Reading involves complex visual and cognitive processes. Printed text is an aggregation of letters in horizontal lines, and the repeated patterns of letter formations may create anomalous visual effects, such as illusory colours, shimmering and vertical motions throughout the body of the text. These illusions are frequently accompanied by somatic reactions, such as nausea, eyestrain, headache and tiredness from reading. Readers who are affected by these discomforting symptoms may complain about the "blinding whiteness" of the page and the experience of "moving" "tilting" and "blurring" letters. These unpleasant experiences indicate visual stress. Visual stress refers not only to the perceptual distortions and discomfort that can be elicited during reading, but also to similar experiences in many environments where stripes, dots, repeated geometrical patterns or flickering lights appear. Watching television, computer screens or even whiteboards can be visually stressing.

Comparing the benefits of Overlays and Reading Rulers

The positive effects of coloured overlays to reduce visual stress and to improve reading speed and comprehension of printed text have been confirmed in several previous studies. Statistical data have shown that 5% of children in mainstream schools read at least 25% more quickly with coloured overlays (Wilkins, 2002). Recently, both full page (A4) coloured overlays and smaller coloured reading rulers have been developed by Crossbow Education Ltd. In this study a comparison was made between the Crossbow A4 coloured overlay and the eye level reading ruler, to see if the size of the reading aids makes a difference to children's reading speed and skills.( Editors' note: The A4 overlays were cut in half for the purposes of the study, to accommodate the format of the children's reading material. The purpose of the study was to compare the benefit of covering a whole page of text (with an overlay) with the effect of tinting a specific area of text (with a reading ruler).

The Study

Seventy-eight children aged between four and seven years participated in a reading assessment with ten colours (pink, magenta, purple, sky, aqua, jade, grass, celery, yellow and orange). Their reading levels ranged from 1 to 7. Thirty-nine children were tested with A5 overlays, and thirty-nine with reading rulers. The reading assessment was to read aloud a short passage of common words arranged in a random order (the "Rate of Reading Test "(Wilkins, 2003)). Time taken and errors were recorded. Both groups also read the text with no reading aid, to provide a baseline reading rate. This study showed that all but four children experienced improvements in both the reported clarity of the text and in the speed of their reading using either type of coloured reading aid. Interestingly, sometimes the colour that was the most beneficial/effective (resulted in the fastest reading speed) was not always the same as the colour that was judged to be the most comfortable (provided the best clarity of the text). The four children who did not benefit were some of the eldest, with a higher reading level to begin with.

Clarity, visibility and freedom to read.

Both the 'most-comfortable-colour' and the 'most-effective-colour' improved reading speed compared to the baseline, no reading aid assessment, but the 'most-effective-colour' improved it to a significantly greater extent.
The maximum improvement of reading speed varied between 23.07% - 38.34% in the overlay condition and between 19.95% - 31.57% in the reading ruler condition. Correlations between the children's reading level and the maximum improvement achieved by the child with their 'most-effective-colour' revealed that the less experienced readers benefited more from the usage of overlays: the largest improvement was observed with children whose reading skill was low. The same pattern was not observable with the usage of the reading rulers. When the children were offered a reading aid to take away with them, the majority chose the 'most-effective-colour', and the majority chose A5 overlays (74%) rather than reading rulers. They explained their choice by referring to better clarity, visibility and freedom to read.

Following the Line

Thirteen of the twenty children who chose the reading rulers to take away with them had compulsive, repetitive behaviour pattern while reading, accompanied with finger pointing, head tilts, eccentric viewing and swinging upper body movements, which are overt signs of reading difficulties and visual stress. These children also expressed that they wanted to have the reading ruler, because it "helped them to follow the line properly". Considering the colour choices of the children, there were no really clear trends: the colour choices seemed to be idiosyncratic. Yellow was a popular colour, but the largest number of fastest reading times was measured with celery overlays. In the reading ruler condition, magenta and sky enhanced reading speed the most.


Largest improvement  seen in the 5 and 6 year old children

The effect of the colours that produced the fastest reading speed was also assessed separately by measuring near binocular visual acuity. The 'most-effective-colour' improved near visual acuity in 34.61% of the participants. A follow up study has retested twenty of the children after three months to determine how many have continued to use their reading aids, and whether the improvements seen in the initial assessment are maintained. This will be reported in due course as it is work in preparation. Preliminary analyses suggest the largest improvement is seen in the 5 and 6 year old children. Reading rulers appear to be preferred to the A5 overlays after three months. Thus, overlays appeared to be preferred during the initial assessment, but this preference may change with use to a preference for reading rulers. It is likely that the best reading aid for a child varies with that child's abilities, experience with the aids and reading style.

"I just read, read, read"

During the assessments children frequently reported that they see with certain colours "properly" or they said "Wow, the letters got bigger!". Some of them said about the overlays "I just read, read, read and do not need to move my eyes." or "It lets my eyes run". Students who preferred the reading rulers better said "It keeps me in the line, I am not getting lost". They enjoyed the participation, were proud of their reading aids and on many occasions reminded their teachers in silent reading time, that they wished to use their chosen coloured reading aid. In summary, due to the possible benefits of the coloured overlays and eye level reading rulers, such as those manufactured by Crossbow Education Ltd., students may reduce their sense of failure in reading, prevent inattention, increase their interactions in all activities in the classroom and receive encouragement to find more joy in reading. This work was conducted at Birkbeck College, University of London, by Judit Veszeli and Dr Alex Shepherd. The research could not have been completed without the generous support of Crossbow Education Ltd.


References: Wilkins, A.J. (2002). Coloured overlays and their effects on reading speed: A review. Ophthalmic and Psychological