1. A method for determining a likelihood of a visual deficit in a subject by way of a simultaneously multi-temporal visual test, the method comprising: a. simultaneously displaying at least two visual patterns to a first eye of a subject, each pattern reversing in contrast or color at a different one of a corresponding number of display frequencies, a first of said patterns displayed to a first region of the subject's visual field and a second of said patterns displayed to a second region of a subject's visual field; b. sampling electrical activity of the brain of the subject to produce a first signal corresponding to the first pattern and a second signal corresponding to the second pattern; c. resolving one or more frequency components from each of said first signal and said second signal; d. repeating steps a-c for the second eye of a subject where a first and second visual field region of the second eye correspond to the first and second visual field region of the first eye; e. comparing at least one frequency component from a first or second signal in a first eye to at least one frequency component from a respective first or second signal in a second eye; and d. determining from one or more of the comparisons a measurement of a likelihood that a visual deficit exists in a visual area being tested.