In this study, we report the existence of correlation between the ability of the object perception in the presence of the external noise and the cognitive functioning in schizophrenia. The level of the internal noise of the visual system have been measured for the 41 healthy volunteers and for the 68 schizophrenia patients in the task of distinguishing the location of the rupture of the Landolt ring, under the conditions of external interference. The collected evidence demonstrated an increase in the level of internal noise of the visual system in the patients with schizophrenia.