Temporal and spatial aspects of sensory interactions during human fusional response were investigated using band-limited, 10th-derivative-of-Gaussian patterns confined to separate regions of the visual field. Experiments were performed to investigate the time course of sensory interactions using the horizontal sensory fusional amplitude (SFA) and the sensory fusional range (SFR) as measures of the interaction. The nature of sensory interactions across the spatial domain has been found to be a function of stimulus duration and time course. These interactions included both enhancements and reductions of SFAs as well as reductions and shifts in SFRs. Two functional components of sensory fusional interactions have become apparent. A fast component is manifested through a global reduction of SFAs while a slower component exhibits both enhancement and reduction of SFAs. The fast and slow components exhibit spatial summation; however, temporal summation within a local region of the visual field is not observed.