Touchscreen device size suitable for non-visual icon search by blind users

Abstract

Blind smartphone users are on the rise and they need to know which device is easiest for them to use. To explore the optimal touchscreen size for devices used by the blind, we conducted an experiment in which 15 blind participants searched for target icons with four touchscreen devices ranging in size from 4 to 7.9 inches. We analyzed the search time, search strategies, and subjective evaluations and found that the 4.7-inch screen device produced the shortest search time and obtained the highest subjective rating among the four devices. These findings are consistent with those in a previous study with sighted participants. One interesting difference is that the blind participants in this study found the icons about 20% to 40% faster than the sighted participants. Another important finding is that the search strategy had a larger effect than the screen size on the search time. These findings are useful for blind people and their supporters at the stage of obtaining new smartphones and learning how to use them.