Characteristics of Visual Contrast Sensitivity and Ocular Microtremor in Schizophrenia

Abstract

Background: schizophrenia is a severe mental illness characterized not only by cognitive but also sensory impairments, including the visual system. Research suggests impairments in contrast processing in schizophrenia, but evidence regarding the nature of these impairments is inconsistent. The theory of tremor modulation signal connects contrast sensitivity with the parameters of ocular microtremor – high-frequency and low-amplitude micromovements that are controlled by neurons of the nuclei of the brain stem. The parameters of ocular microtremor in psychopathology, in particular in schizophrenia, have not been described in the scientific literature.The aim of the study was to study the characteristics of contrast sensitivity and microtremor of the eyes of patients with schizophrenia.Patients and methods: to register contrast sensitivity, the method of computer visocontrastometry was used. Gabor elements were presented with spatial frequencies of 0.4, 1.0, 3.0, and 10 cycles/deg. Eye microtremor was recorded using a non-contact high-speed video recording method using an original optical system. The study involved 30 patients diagnosed as paranoid schizophrenia and 30 people without psychopathology and neurological diseases.Results: the contrast sensitivity of patients was reduced in the region of medium and high spatial frequencies compared with conditionally healthy controls, which may be associated with the chronic course of the disease. Ocular microtremor in the patient group was characterized by a lower frequency and a higher amplitude compared to the control group.Conclusions: contrast sensitivity and ocular microtremor are considered as potential markers for determining the functional state in schizophrenia, which requires further research and accumulation of experimental data.