There are two types of signal differentiation in the mammalian visual system : ( 1 ) In respect to time which is compensated by the saccadic movements ( in humans ) and ( 2 ) spatial differentiation in respect to retinal, let's say polar coordinates.
12.
It can also be noted that there are three different types of eye movements : vergence movements, saccadic movements and pursuit movements . "'Vergence movements "'involve the cooperation of both eyes to allow for an image to fall on the same area of both retinas.
13.
Nystagmus can be caused by subsequent saccadic oscillations ) such as opsoclonus or ocular flutter that are composed purely of fast-phase ( saccadic ) eye movements, while nystagmus is characterised by the combination of a smooth pursuit, which usually acts to take the eye off the point of regard, interspersed with the saccadic movement that serves to bring the eye back on target.