New insights into visually impaired patients' preferred reading illumination and home‐based reading speed with new task‐lighting

Abstract

Introduction When optimal lighting is applied to hard‐copy materials for visually impaired individuals, laboratory‐based reading performance can improve significantly. However, it is not known whether their lighting preferences are related to ocular factors or if laboratory‐based reading improvements will translate to home‐based environments. Methods Preferences for brightness (lux) and colour temperature (degrees Kelvin; K) with the LuxIQ/2 for ‘most comfort’ while reading at near were evaluated in‐clinic for 71 adults with ocular disease affecting the outer (n = 37; 52%), inner or all retinal layers (n = 34; 48%). Twenty participants received either an OttLite Cobra lamp or a generic gooseneck lamp with a bulb resembling LuxIQ/2 parameters for their preferred reading light, and then completed home‐based telephone evaluations using the sustained silent reading test. Results Participants with outer retinal disease preferred significantly brighter light intensity by an average of 838 lux versus those with inner retinal disease (95% CI: 331, 1344; p = 0.002). No participants opted for a coloured tint for reading based on the LuxIQ/2 measurements since they preferred white light only; most preferred the OttLite Cobra lamp. At home, reading speed improved significantly by an average of 37 words per minute with the new lamp (95% CI: 12, 62; p = 0.005). Conclusions Patients with outer retinal disease prefered brighter light intensity for reading. Clinic‐based lighting preferences yielded improvements in reading speed when using a new task light at home.