Preliminary Investigation of the Optimal Size on Tactile Pictogram for Visually Impaired Persons

Abstract

The purpose of this study was to investigate the optimal size of tactile pictograms for visually impaired persons. Thirty blindfolded subjects actively touched haptic stimuli from embossed Japanese Industrial Standard (JIS) - type pictograms of five sizes (30 mm², 60 mm², 90 mm², 120 mm², and 150 mm²).
We assessed the haptic performance (percentage of correct answers, reaction time, complexity, incomprehensiveness, and confidence) and examined the association between haptic performance and cognitive functions (intelligence and visual memory). Our results showed that haptic performance on the 120 mm² and 150 mm² sizes outperformed those on the other sizes. However, we ascertained that the percentage of correct answers and reaction times on the 120 mm² size were affected by visual memory. Thus, it appears that the optimal size for tactile pictograms for visually impaired persons is the size ranging from 120 mm² to 150 mm².