A method for determining a likelihood of a visual deficit in a subject uses a simultaneously multi-temporal visual test. At least two visual patterns are simultaneously displayed to the subject. Each pattern reverses in contrast or color at a different display frequency, and each pattern is displayed to a different region of the subjects visual field. Electrical activity of the brain of the subject is captured and sampled, and one or more frequency components are resolved from the resulting signal, where each frequency component corresponds to a different display frequency. The method then involves determining from the frequency components, optionally by comparison between the eyes, a measurement of a likelihood that a visual deficit exists in a particular area.
