The advantages of steady-state EP recording include (1) speed in assessing sensory function in normal and sick infants (e.g., in amblyopia) and in sick adults (e.g., in multiple sclerosis); (2) monitoring certain activities of sensory pathways that do not intrude into conscious perception; (3) rapidly assessing sensory function when a large number of subjects must be tested (e.g., in refraction); (4) objective measurement at very high suprathreshold levels where psychophysical methods are difficult or ineffective; (5) rapidly assessing sensory function in normal subjects when EP variability and nonstationarity preculde lengthy experiments; and (6) proving a speedy objective equivalent to behavioral test in animals.