Multiscale analysis of equatorial sclera anisotropy: Revealing discrepancies in fiber orientation and mechanical properties

The sclera, the eye's primary load-bearing tissue, substantially influences the globe's response to intraocular pressure. Although the mechanical properties of the anterior and posterior segments have been extensively studied, the equatorial sclera's properties remain underexplored, limiting our understanding of ocular conditions like myopia, ocular trauma, and glaucoma. Traditional studies that rely solely on fiber orientation to explain scleral mechanics may overlook the tissue's complex biomechanical behavior. To address this gap, we conducted a comprehensive investigation using ultrasonic elastography, optical coherence elastography, and polarizing light microscopy to analyze the equatorial sclera's anisotropic properties. Our findings reveal a counterintuitive result: Mechanical anisotropy in the equatorial sclera contradicts preferred fiber orientation. This integrated approach not only challenges prevailing models of scleral biomechanics but also provides fundamental insights into the mechanisms underlying key ocular conditions, highlighting the importance of multimodal and multiscale analyses in biological tissue research.