Description: The research is based on the statement that retina produces the proper level of electrical activity, sourcing visual system. I started the research with partial darkening of different parts of the visual fields of humans to register possible psychological and physiological changes. The tested showed dramatically increasing variability and number of changes within just four exact types of darkening. More, emotional and physiological aspects of those changes were polarized into general acceptance and general rejection of a certain type of darkening in most of the individual tests. Thus the tested formed two opposite groups within every one of those types of darkening: a group with general negative reactions and a group with general positive ones. Further, those types of darkening turned out combined in pairs. General tune of reactions of most of the tested changed to strictly reverse within a pair of upper-lower types of darkening of peripheral vision and outer-inner ones as well. Between the pairs of types of darkening, there was no correspondence. The tested showed stability of their reactions during at least several months. Thus I may state a possibility of existence in the visual system of humans of two independent neuropsychological structures both having two alternative modes of functioning with a stable preference of just one of them in every individual case. If it is true, there may be a vision-based typology.