Psychophysics of reading--X. Effects of age-related changes in vision.

This study examined the influence of age-related changes in vision on reading performance. Maximum reading speed was measured in groups of young (n = 16, mean age 21.6 years) and old (n = 14, mean age 68.3 years) subjects, all with acuities of 20/32 or better. A psychophysical procedure was used for measuring reading speed that has proven reliable and sensitive to visual factors in previous research. Data were collected for character sizes ranging from .15 degrees to 12 degrees. Research revealed that old subjects who were free of eye disease read as fast as the young subjects for character sizes ranging from .3 degrees to 1.0 degrees. This is the range in which reading speed is maximum for young subjects. Research also revealed that old subjects showed a deficit when reading text composed of very small or very large characters. Their speeds dropped to about 70% of the young adult speeds. These deficits may be due to age-related losses in visual contrast sensitivity.