Schizophrenia is an illness with a large variety of symptoms, significant variability of the individual course, and still not fully explained etiology. It is suggested that genetic, infectious and immunological factors may be involved, and neurodevelopmental, neurodegenerative and neurotransmitter hypotheses have been proposed. Detection of the measurable and reproducible biological indicators of the clinical picture and the course, referred to as biomarkers, may be essential to elucidate the etiopathogenic mechanism of the illness. For schizophrenia, this function may be performed by the retina of the eye and other elements of the visual pathway. The observed abnormalities are of a structural and functional nature. They concern virtually the entire visual system, and, in accordance with the neurodevelopmental theory of schizophrenia, arise at the early stages of brain formation. What is essential – the specific structure of the human eye, its translucency, lack of myelin and low concentration of glial cells provide excellent opportunities for non-invasive assessment of the microstructure and function of the central nervous system. The following paper discusses the most important changes in the visual apparatus observed in patients with schizophrenia. Particular attention was paid to retinal vascular changes, anomalies in the electroretinogram and optical coherence tomography, structural and functional disorders of cortical centers and neurochemical disorders in the cells of the visual pathway.