Abstract
Background: Coloured lenses and light are used to optimise reading in a several patient groups such as those with reading difficulties, migraine, and low vision. The underlying mechanisms are poorly understood. Northway et al (2010) have shown that coloured lenses reduce the effects of noise in visually symptomatic readers. Purpose: To evaluate how reading speed and accuracy are affected by variations in spectral wavelength and noise. Methods: Ten participants (18-45 years) read under three different colours of light to align with L cone, M cone and S cone function using spectrally controlled LED lights under controlled levels of luminance (30 lux). Normal English words with 0, 0.3and 0.6 spatial noise created by displacement of the letters were read aloud for 1 minute and recorded. The average number of words read was calculated under each of the conditions and statistical analysis was carried out. Results: Reading speed was not significantly affected by colour (Anova p=0.25). The introduction of noise significantly reduced reading speed (Anova p< 0.0001). As noise increased reading speed reduced further however reading speed in blue light ( S cone) was least affected by noise and was significantly better in short wavelength light when compared with reading speed under long or medium wavelengths when noise is present. (Anova, Tukey correction P< 0.0001). Conclusion: Reading speed does not seem to be affected by colour directly. Spatial noise does however reduce reading speed but this effect is least when short wavelength light is used. Those who complain of visual symptoms when reading may be more adversely affected by noise and as such these results would suggest that blue light or filters would be the maximal colour to reduce the effects of noise when reading.
Meeting abstract presented at VSS 2017