1. A method of assessing eye function, comprising: (a) providing an image area in which images can be presented to the eye, and in which the luminance of any point in the image area over the desired field of view under test can be defined at least as accurately as the desired accuracy of a retinal map to be obtained; (b) forming a fixation image; (c) presenting a stimulus to the eye at a location within the image area spaced from the fixation image; (d) detecting a saccade triggered by said stimulus and immediately removing the original fixation image and creating a new fixation image at said location; (e) recording the timing and magnitude of the saccade and the subsequent fixation; (f) repeating steps (c) to (e); and (g) comparing the results with a database of typical eye responses.