MReye-Seg: development and validation of an automated MRI pipeline for standardised ocular and orbital morphometrics

Robust and objective quantification of ophthalmic and retroorbital structures from standard neuroimaging is an accessible but still untapped resource for clinical assessment. Current approaches mostly rely on subjective manual measurements, introducing variability and limiting clinical integration. We developed and validated an automated ocular morphometrics pipeline enabling diagnostic precision through standardised orbital measurements.

The presented pipeline consists of: (1) supra-resolution orbital template generation from standard structural MRI, (2) expert-guided segmentation with anatomical landmark annotation, (3) registration-based propagation to individual scans, (4) ocular neuroimaging quality control, and (5) automated extraction of 38 bilateral volumetric and geometric parameters critical for comprehensive ophthalmic and ocular structural morphometry including entire optic nerve sheath volume. We also integrated posterior globe deformation mapping for structural analysis.

High-resolution orbital space template generation and subsequent landmark-based segmentation succeeded for all tested T1- and T2-weighted datasets. Ocular morphometrics revealed a substantial and significant physiological asymmetry between the eyes with minimal-to-negligible inter-dataset variations for all orbital parameters and landmarks. The pipeline demonstrated excellent reproducibility with intraclass correlation coefficients exceeding 0.8 for 30/38 metrics. We then established normative ranges from adult datasets to facilitate clinical and research interpretation. Our posterior globe deformation mapping enables sensitive morphological assessment.

This pipeline ( https://github.com/Eulenburg-LMU/MReye-Seg ) enables objective, standardised and comprehensive quantification of ophthalmic morphometrics, including total optic nerve sheath volume and posterior globe deformations as potential surrogates for raised intracranial pressure. By minimising measurement variability and processing time, MReye-Seg supports eye researchers and ophthalmologists in achieving diagnostic precision for ocular and retroorbital conditions.