A method for assessing the function of at least one sensory field of a subject, and apparatus and systems for carrying out the method, the method comprising: using a display, presenting stimuli to selected locations of the sensory field, the selected locations being centred at points on a sampling grid spanning a portion of the sensory field, wherein the individual stimuli if presented simultaneously at the sampling grid points would overlap in the space defined by the sensory dimensions of the field using a sensor, detecting responses in the subjects sensory field evoked by the stimuli and processing the detected responses to relate them to the function of the subjects sensory field at the selected locations.
