Design and clinical evaluation of a virtual reality-based system for automated ocular deviation measurement

Accurate measurement of ocular deviation is essential for strabismus assessment and treatment monitoring. Conventional methods such as the prism alternating cover test require trained examiners and substantial patient cooperation, which may introduce inter-examiner variability and limit measurement standardization. We developed a virtual reality (VR)-based system for automated horizontal ocular deviation measurement. The system simulates a prism alternating cover test in a controlled VR environment to guide fixation and record eye movement videos under standardized visual conditions. Recorded videos are processed using a multi-stage pupil localization and tracking pipeline to maintain robust performance under partial occlusion and blinking, and extracted pupil trajectories are converted into quantitative estimates of horizontal ocular deviation. In a pilot clinical evaluation, the system achieved over 93% agreement with clinician diagnoses in identifying horizontal ocular deviation categories, with a mean angular error of 0.35 ± 1.09° relative to reference clinical assessments. These findings demonstrate the feasibility of a VR-based automated system for standardized horizontal ocular deviation measurement and support its potential value for objective strabismus-related assessment.