Assessing optimal colour and illumination to facilitate reading

Abstract

Purpose: This study examined the effectiveness of the LuxIQ, the Apple iPad and a smart bulb in assessing optimal colour and illumination to facilitate reading in younger, older and visually impaired adults.

Methods: Participants read standardised texts at baseline (normal lighting/no device), then using the Apple iPad, LuxIQ and smart bulb, with their normal vision (20/20 condition) and using a simulated reduction in visual acuity/contrast sensitivity (20/80 condition). Visually impaired participants followed the same procedure used in the 20/80 condition.

Results: There was a significant interaction between condition and device in younger, F(1.5, 43.51) = 30.41, p < 0.001, ω² = 0.34 and older, F(1.5, 4.51) = 4.51, p = 0.03, ω² = 0.05 adults with normal vision, and there was a significant effect of device, F(2, 58) = 5.95, p = 0.004, ω² = 0.12 in visually impaired adults. In the 20/20 condition, age and colour predicted reading speed, F(3, 176) = 36.25, p < 0.001, Adj. R² = 0.37, whereas age, lighting and colour predicted reading speed, F(3, 176) = 36.25, p < 0.001, Adj. R² = 0.37 in the 20/80 condition. In the visual impairment condition, lighting, colour and impairment severity predicted reading speed, F(3, 85) = 10.10, p < 0.001, Adj. R² = 0.24.

Conclusions: The clinical implications of this study are that reading speeds improve in individuals with low vision under improved lighting conditions, specifically, with higher levels of luminance and colour temperature. The effectiveness of the devices varied across groups; however, the LuxIQ was the only device to improve reading speeds from baseline in older adults with visual impairments.

Keywords: colour; lighting; low vision; low vision rehabilitation; reading.