MRI-Based Normative Orbital Anthropometric Measurements in Pediatric Populations: Age-Related Variations and Clinical Implications

Purpose: Precise and reliable anthropometric reference data for the pediatric orbit is crucial for accurately diagnosing orbital disorders, detecting developmental abnormalities, and planning effective surgical interventions. This study aimed to establish comprehensive MRI-based normative orbital measurements in a pediatric population, explore clinically meaningful age-related variations, and assess measurement reliability across multiple neuroradiologists. Methods: In this retrospective study, we analyzed MRI scans from 64 healthy pediatric patients (32 males, 32 females; age range 1–17 years) acquired at both 1.5 Tesla and 3 Tesla MRI systems. Patients were categorized into preschool (1–6 years), school-age (7–12 years), and adolescent (13–17 years) groups. Three expert neuroradiologists independently measured clinically relevant orbital parameters including extraocular muscle thicknesses, orbital breadth and height, interzygomatic distance, intercanthal distance, optic nerve sheath width, and optic nerve angle. Data were statistically evaluated using Spearman’s correlation, Kruskal–Wallis tests, Mann–Whitney U tests, and intraclass correlation coefficients (ICCs) for reliability assessment. Results: We provide detailed, MRI-derived normative data for essential pediatric orbital structures, highlighting significant and clinically meaningful age-dependent anatomical changes. Notably, the interzygomatic distance demonstrated the strongest correlation with age (r=0.772, p<0.001), underscoring its clinical relevance in developmental assessment. Orbital breadth (right: r=0.674; left: r=0.703) and orbital height (right: r=0.608; left: r=0.644; all p<0.001) also increased significantly with advancing age, offering clear reference values for clinical practice. Conversely, certain parameters such as optic nerve angle exhibited remarkable stability across age groups, providing consistent normative benchmarks. Interobserver reliability among neuroradiologists was excellent (orbital breadth ICC=0.92; orbital height ICC=0.90), reinforcing measurement robustness. Conclusions: This study delivers precise MRI-based normative pediatric orbital anthropometric data, clearly identifying age-related developmental trends and stable anatomical landmarks. These reference measurements can significantly aid radiologists and surgeons in the accurate identification of orbital pathologies, the detection of subtle developmental anomalies, and in optimizing surgical planning and clinical outcomes in pediatric orbital cases.