Novel Methods for Assessing and Rehabilitating Binocular Sensorimotor System in Virtual Reality

The ability to coordinate the two eyes to achieve a stable and unified perception of the world is a fundamental aspect of human vision. This process, which relies on the continuous interaction between sensory and motor components, allows us to perceive depth and maintain precise alignment during everyday activities. When this coordination fails, as in strabismus or amblyopia, binocular function deteriorates, leading to abnormal fixation, loss of stereopsis, and suppression of one eye. Despite technological advances, quantitative and ecologically valid tools for assessing and treating binocular sensorimotor coordination are still limited, particularly in clinical contexts where eye misalignment hinders the use of conventional eyetracking systems. With these premises in mind, the general goal of my PhD research was to develop and validate novel methodologies for the quantitative assessment of binocular coordination in immersive virtual environments, and to extend the use of HMD-based eye tracking to individuals with atypical binocular vision. The first step was the implementation of a monocular calibration framework for head-mounted displays with integrated eye trackers, capable of providing accurate gaze estimation even when built-in calibration fails due to asymmetric fixation or ocular deviation. Modelling headset–eye system individual geometric and optical parameters allowed a precise monocular gaze mapping that could overcome the limitations of standard manufacturer procedures. Building upon this, I developed a digital version of the clinical cover test, which enables direct measurement of ocular deviations in VR while controlling viewing parameters such as head orientation, occlusion timing, and fixation distance. Experimental results demonstrated that the monocular calibration significantly improves spatial accuracy and reduces systematic bias across the visual field compared to standard methods. Validation was carried out on both healthy participants and individuals with binocular misalignment, confirming the robustness of the approach in clinical conditions. The digital version of the cover test revealed consistent patterns of phoria modulation with head rotation and provided quantitative evidence for optimal occlusion durations required to capture full eye realignment dynamics. Overall, the methods and tools developed in this work offer a new experimental framework for studying binocular sensorimotor coordination with high precision and ecological validity. These advances pave the way for future applications of virtual reality in clinical research, offering non-invasive, adaptive, and quantitative tools for the assessment and potential rehabilitation of binocular visual disorders.