Gizem Dogancali Yanchev‡, Petranka Chumpalova-Tumbeva‡, Ivanka Veleva§, Kaloyan Stoichev§, Snejena Murgova|, Georgi Balchev|, Emiliya Dimitrova-Ilieva§, Aleksandar Todorov§, Stanislav Kapinchev§Corresponding author: Gizem Dogancali Yanchev ( gizemdgncl@gmail.com ) Corresponding author: Petranka Chumpalova-Tumbeva ( chumpalova@abv.bg ) Academic editor: Galya Stavreva © Gizem Dogancali Yanchev, Petranka Chumpalova-Tumbeva, Ivanka Veleva, Kaloyan Stoichev, Snejena Murgova, Georgi Balchev, Emiliya Dimitrova-Ilieva, Aleksandar Todorov, Stanislav Kapinchev. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Citation:
Yanchev GD, Chumpalova-Tumbeva P, Veleva I, Stoichev K, Murgova S, Balchev G, Dimitrova-Ilieva E, Todorov A, Kapinchev S (2026) Exploratory eye movement patterns in schizophrenia and their potential as biomarker. Journal of Biomedical and Clinical Research 19: 43-57. https://doi.org/10.3897/jbcr.e183844 |  |
Eye movements represent an objective, quantitative indicator of the integrity of cognitive and perceptual processes. Since the beginning of the 20th century, research has shown that individuals with schizophrenia demonstrate characteristic deviations in smooth pursuit, -egulation, and visual exploration behaviour. These oculomotor alterations are linked to dysfunctions in attention, executive control, and perceptual organization, and have been discussed as potential biomarkers of impaired neural network regulation. More recent work further implicates disturbances in visual attention and integration, as well as reduced executive control over oculomotor activity, which may manifest in altered gaze behaviour.
Building on this literature, the present study examined whether free-viewing eye-movement patterns capture markers of restricted exploration and altered scanpath organization under ecologically valid conditions. We recorded eye movements during passive viewing of landscape and abstract images in three groups: patients with schizophrenia (n = 30), healthy controls (n = 30), and close relatives (n = 21). Visual exploration was quantified using integrative indices of fixation number and duration (mean/median/total), scanpath length, coverage fraction, spatial dispersion (mean/median; dispersion_x and dispersion_y), center bias, fixations per second, gaze entropy (bits), and saccade metrics. Group and image type were tested in 2 × 2 mixed ANOVA models with FDR correction across metrics.
In the patient-control analysis (N = 60), a significant main effect of group was observed across multiple exploration and oculomotor parameters after FDR correction (partial ηp² ≈ .12–.21; pFDR ≤ .032), with no main effect of image type and no group × image type interaction surviving correction, supporting a stimulus-nonspecific alteration of visual exploration in schizophrenia. In the relatives-controls analysis (N = 51), uncorrected trends suggested a more compact scan pattern (reduced dispersion and saccade amplitude). However, no effects remained significant after FDR correction. Overall, free-viewing eye-movement metrics showed medium-to-large, stimulus-nonspecific group differences in schizophrenia, consistent with a restricted and altered exploration mode, whereas potential vulnerability-related signals in first-degree relatives were weaker and did not survive correction, indicating the need for larger samples and/or targeted paradigms with predefined core metrics in familial-risk designs.