Nanoscale biomechanical remodeling in human myopic corneal lenticule revealed by quantitative dynamic AFM.

Increasing evidence shows that myopia, a prevalent ocular disorder and the leading cause of visual impairment worldwide, is associated with significant alterations in the biomechanical properties of the sclera. However, the role of the anterior ocular segment, particularly the hierarchical collagen structure and biomechanical behavior of the corneal stroma, remains poorly understood in the context of myopia development. There is an urgent need to elucidate the relationship between nanoscale changes in corneal collagen ultrastructure, tissue-level biomechanical properties, and the macroscopic progression of myopia. In this study, we used quantitative dynamic atomic force microscopy and transmission electron microscopy to investigate the ultrastructure and biomechanical properties of the corneal stroma in human myopic eyes. Our results demonstrate that with increasing myopia severity, collagen fibril density progressively decreases, fibril packing becomes sparser, and interfibrillar spacing widens. Nanomechanical characterization further revealed decreased stromal stiffness and reduced mechanical stability, indicating a diminished capacity of the tissue to bear mechanical loads. Collectively, this correlative analysis highlights the pivotal role of corneal stromal nanostructure and biomechanics in the pathological development of myopia, providing new insights that could aid in the characterization, diagnosis, and assessment of the condition.