Experimental psychologists Iain Gilchrist and John Findlay (2003: 1-6) champion a paradigm for vision, based on coupling between the structural “inhomogeneity of the retina” and the ubiquity of eyeball movements. Previously these striking phenomena had been regarded as “incidental” rather than fundamental features of the visual system. Their “viewpoint is not widely current.” They note that “[m]any texts on vision do not even mention that the eye can move.” They declare that:

Active vision takes as its starting point the inhomogeneity of the retina, seeing the fovea not simply as a region of high acuity, but as the location at which visual activity is centred.

It has been calculated that a hypothetical human retina supporting the concentration of cone cells actually found the fovea would require a brain visual cortex “weighing perhaps ten tons.” Taking an evolutionary approach, Gilchrist and Findlay (2003: 5) hold that:

A mobile eye constructed on the principle of the vertebrate eye is not a co-incidence or a luxury but is very probably the only way in which a visual system can combine high resolution with the ability to monitor the whole visual field.

John M. Findlay and Iain D. Gilchrist (2003) Active Vision: The Psychology of Looking and Seeing. Oxford University Press. Oxford, UK.