Computerized behavioral method for eye-glasses prescription

A system for determining an optical error of a subject, comprising an apparatus adapted to display to said subject stimuli comprising blurred images, a data collection apparatus suitable to collect the responses of said subject to stimuli presented to said subject, a database comprising test results of users with different optical errors, who were tested with different parameters, resulting in a detailed correlation between the optical error and the optimal blur discrimination, and logic means adapted to compare between the responses of the subject with the data contained in said database.