Increasing reading speed by using colours - Issues concerning reliability and specificity, and their theoretical and practical implications

Oct 22, 2026

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Precision ophthalmic tinting can help readers who report perceptual distortion of text: an illumination colour can eliminate distortions and increase reading speed. Green or blue are common choices, yet optimal chromaticity varies markedly across individuals. Across test sessions, the fastest chromaticity is stable for each person but highly specific, with deviations of about 6 JNDs largely removing speed gains. Numerical analysis of 1000 tint prescriptions suggests most lighting changes still preserve potential benefit, except weakly saturated or purple tints.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages13

Reading Time33 min

AccessFree to download

Abstract

1 Introduction

2 Study 1

2.1 Participants

Perception, 2005, volume 34, pages 109 ^ 120 DOI:10.1068/p5045 | Increasing reading speed by using colours: Issues concerning reliability and specificity, and their theoretical and practical implications | | --- | | Arnold J Wilkins, Nirmal Sihra, Andrew Myers
Visual Perception Unit, Department of Psychology, University of Essex, Colchester CO4 3SQ, UK;
e-mail: [arnold@essex.ac. uk](arnold@essex.ac. uk)
Received 30 January 2003, in revised form 25 May 2004; published online 21 January 2005 | Abstract. By using techniques for precision ophthalmic tinting, individuals who report perceptual distortion of text can often find a colour of illumination that eliminates the distortions and increases reading speed. Most individuals choose green or blue hues, but there is considerable variability. We investigated how specific the colour has to be to obtain optimal reading speed. Individuals who habitually wear coloured filters for reading were asked to read text illuminated by coloured light (without using their filters). Reading speed was measured repeatedly with light of different colours. The colour (chromaticity) at which reading was fastest was consistent from one test session to the next. It was different from one individual to another, but highly specific for each individual: departures of colour from optimum by about 6 JNDs eliminated most of the speed advantage conferred by the optimal colour. It was difficult to attribute the consistency and specificity simply to familiarity with the tint or immediate memory for the colour of illumination. A consecutive sample of 1000 tint prescriptions was analysed numerically. For most prescriptions the variation in chromaticity with different types of lighting was not such as to remove all the potential benefit of the tint, as judged from a model of the effect of chromaticity on reading speed. The exceptions were the few tints that were weakly saturated or purple in colour. Across participants, reading speed was not consistently related to the scotopic energy, to the energy captured by any cone class, or to opponent colour processes. The reading was generally slowest with white light, and not with the colour complementary to the optimum. Explanations in terms of magnocellular deficits and cortical hyperexcitability are briefly discussed. 1 Introduction The MRC system for precision ophthalmic tinting (Wilkins et al 1992a) was introduced in the UK in 1993 and since then more than 25 000 people have been prescribed coloured glasses to help with reading. Placebo-controlled studies have demonstrated that the effects of colour on reading fluency are specific and different for each individual (Wilkins et al 1994, 2002) but precisely how specific the tint has to be is not yet known. The following studies were performed to explore the specificity of the effect of colour on reading fluency. They suggest that central mechanisms underlie the effect. The individuals who benefit from coloured filters usually complain of perceptual distortions of the text such as apparent movement of the letters, blurring, or coloured halos; distortions that abate when the text is illuminated by coloured light (Wilkins et al 1992b). These individuals have abnormally large microfluctuations during steadystate accommodation (Simmers et al 2001b). The fluctuations are reduced when the coloured glasses are worn, but also when neutral filters of similar photopic transmission are worn, suggesting that, although the microfluctuations of accommodation are a physiological sign of an underlying abnormality, they are not a cause of the perceptual distortions, nor their reduction with colour. Instead, the mechanisms for the benefit of colour appear to be central in origin. This is because the colour optimal for use in overlays, which cover the page and provide a surface colour, is different from the colour optimal for use in lenses, which colour the entire visual scene (Lightstone et al 1999). 110 A J Wilk

FAQs

How can colour illumination reduce text perceptual distortions and improve reading speed?

Readers who experience perceptual distortion can often find an illumination colour that eliminates the distortions and increases reading speed, using precision ophthalmic tinting techniques.

Is the optimal colour the same for different individuals?

No. The chromaticity that produces the fastest reading speed is consistent across repeated sessions for the same person, but it differs substantially between individuals.

How sensitive is reading-speed benefit to deviations from an individual’s optimal chromaticity?

Departures from the optimum by about 6 JNDs eliminate most of the speed advantage gained from the optimal colour.

Oct 22, 2026

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