Abstract
To determine the optimum size of a braille font, we conducted an experiment in which a popular Japanese braille font was printed at various sizes on capsule paper and read and rated by late blind people. The results show that braille printed at 16 to 19-point sizes was read faster and rated higher than that printed at smaller or larger sizes. These optimum sizes mostly coincide with those found for young congenitally blind people. A new finding was that many reading errors that stemmed from mistaking the range of braille cells were observed at larger sizes, 20 to 22-point sizes. This means that enlarging the font size is not necessarily beneficial for late blind people and optimum sizes should be strictly selected when doing so.
