The present invention tests and/or trains the visual sensitivity of a subject using adaptable visual indicia. One or more visual indicia possessing a visual trait are displayed to the subject. The displayed visual indicia possessing a visual trait may be adjusted to determine when a subject can and cannot be perceived by the subject. A displayed visual indicia may be adjusted in its size, rate of movement, direction of movement, location of display, duration of display, or other characteristic. To determine whether a subject correctly perceived the visual trait possessed by a displayed visual indicia, an input may be received from the subject. If an input received corresponds to the visual trait possessed by the displayed visual indicia, the subject may be determined to have correctly perceived the displayed visual indicia and the visual trait.