Abstract

Our study of the visual requirement of mobility has gradually converged to specifying the visual requirements of an everyday activity: shopping. We determine visual requirements by measuring performance (time and bumps) as a function of type and degree of visual restriction: field, contrast, and resolution. We have found that very modest amounts of field (10°), contrast (4%), or resolution (0.4 cycle/deg) are sufficient for nearly unimpaired travel performance in a laboratory maze and a real shopping mall, when accompanied by the experimenter. Shopping involves walking along, to an approximately known destination, and finding a specific product. We present the results of ongoing experiments to determine the effects of travelling unaccompanied (seems to increase anxiety but not travel time), of finding a specific store in the shopping mall (seems to be similar to just walking to end), and of finding specific groceries in a supermarket (seems to have higher requirements).

© 1985 Optical Society of America