This prospective, multicenter, multinational observational study evaluates the clinical validity of an AI-based quantitative eye movement analysis system (Glandy EOM) that analyzes smartphone-recorded 9-gaze videos. Approximately 200 adults per site with suspected or confirmed ocular motility abnormalities will undergo a single study visit consisting of a standard clinical 9-gaze examination, an assistant-aided smartphone video recording, and a patient self-recorded video acquisition using a mobile application. Because the study population is defined by clinical suspicion or diagnosis of ocular motility abnormality rather than confirmed disease at enrollment, some participants may be clinically judged to have no abnormality on formal evaluation; such subjects remain part of the study population and are not considered healthy volunteers. AI-derived quantitative eye movement metrics (corneal center displacement in millimeters and angular deviation) will be compared with rater-derived measurements obtained from the same videos using a calibrated reference approach, and with clinician-assessed 9-gaze grading. The investigational device is used solely for video acquisition and analysis and does not influence clinical decision-making.

Ocular motility is commonly evaluated using the 9-gaze examination, which relies on clinician observation and semi-quantitative grading. This approach is inherently subjective and can show inter-observer variability and limited sensitivity to subtle changes over time. Objective, quantitative assessment of eye movement remains an unmet clinical need, particularly for monitoring disease progression and treatment response.

Recent advances in artificial intelligence have enabled automated analysis of facial and ocular features from smartphone-recorded videos, offering the potential for reproducible quantitative measurement of eye movement. Glandy EOM is an investigational software-only medical device (SaMD) developed by THYROSCOPE INC. that processes smartphone-recorded 9-gaze videos to generate quantitative eye movement metrics. Glandy EOM has not yet received regulatory approval and is used for research purposes only in this study.

The study is a prospective, multicenter, multinational observational investigation designed to evaluate the clinical validity of Glandy EOM. The study population consists of adults with suspected or confirmed ocular motility abnormalities; healthy volunteers without any clinical indication for 9-gaze examination are not enrolled. Because eligibility is based on clinical suspicion or diagnosis of ocular motility abnormality rather than confirmed disease at enrollment, some participants may ultimately be clinically judged to have no abnormality on formal evaluation; such subjects remain part of the study population. Participants will undergo a single study visit consisting of (1) a standard clinical 9-gaze examination with clinician grading (-4 to +4), (2) a smartphone video recording performed with the assistance of a trained operator using a standardized setup, and (3) a patient self-recorded smartphone video acquired through the study mobile application.

For quantitative reference measurements, independent rater-derived measurements will be obtained from the recorded videos using a calibrated reference approach. A calibration marker of known size will be placed on the glabella during video acquisition to enable real-world scale estimation for the reference measurements. The calibration marker is used only for rater-based reference measurement and is not used by the AI algorithm.

The primary objective is to evaluate agreement between AI-derived quantitative eye movement metrics and rater-derived measurements of corneal center displacement, expressed as distance (mm) and angular deviation. Secondary objectives are to evaluate correlation between AI-derived metrics and clinician-assessed 9-gaze grading, and to evaluate whether AI-derived metrics obtained from patient self-recorded videos are comparable to those obtained from assistant-aided recordings. The investigational device is used solely for video acquisition and analysis and does not influence clinical decision-making during the study.

Inclusion Criteria:

• Adults who have reached the legal age of consent for research participation in the applicable jurisdiction.
• Subjects with suspected or known ocular motility abnormalities.
• Subjects who are able to understand and follow gaze instructions required for the 9-gaze examination, as judged by the investigator.
• Subjects who are able to undergo facial video recording using a smartphone.
• Subjects who provide written informed consent.

Exclusion Criteria:

• Conditions that prevent reliable detection of ocular landmarks in video recordings (e.g., severe ptosis, corneal opacity, or significant occlusion of the eyes).
• Ocular or facial conditions that, in the opinion of the investigator, may significantly interfere with image-based analysis.
• Subjects who are unable to comply with study procedures.

Adults of legal age of consent with suspected or confirmed ocular motility abnormalities, recruited at participating ophthalmology sites.

Some enrolled participants may ultimately be clinically judged to have no abnormality on formal evaluation; these subjects remain part of the study population and are not considered healthy volunteers.

The dataset includes patient-captured smartphone 9-gaze facial videos, which are inherently identifiable biometric data and carry a higher re-identification risk than static images. Public sharing of individual participant data (IPD) would therefore pose a substantial privacy risk that cannot be fully mitigated by standard de-identification of tabular variables alone. The informed consent obtained from participants and the IRB/EC-approved protocol do not authorize broad third-party sharing of these video recordings or associated individual-level records. As this is a multinational, multicenter study, the collected data are also subject to the personal data protection laws applicable in each participating jurisdiction, including the Republic of Korea's Personal Information Protection Act (PIPA), the EU General Data Protection Regulation (GDPR), and the US HIPAA where applicable, which restrict external transfer of identifiable health and biometric information. In addition, the investiga