Brillouin microscopy and optical coherence elastography reveal the role of collagen XIV in corneal stiffness

The mechanical properties of the cornea play a vital role in understanding and characterizing its structure, function, and contribution to overall ocular health. Different ocular treatments and pathologies, such as corneal collagen cross-linking and keratoconus, change these properties and, subsequently, vision. Collagen XIV plays a crucial role in regulating corneal structure and function and is believed to contribute to maintaining its mechanical strength, but its specific function is poorly understood. However, measuring its contribution to corneal stiffness has not been directly studied. Several tools and techniques have been developed to assess the mechanical properties of the cornea. In this framework, Brillouin microscopy, which exploits the interaction of light with spontaneous, thermally induced density fluctuations, has emerged as a powerful, label-free, and non-destructive method for mechanical imaging. On the other hand, optical coherence elastography (OCE) enables us to assess quantitative mechanical characteristics noninvasively using optical coherence tomography (OCT). In this study, a two-pronged optical elastography approach, combining Brillouin microscopy and OCE, was employed to investigate the mechanical effect of collagen XIV deficiency in the murine cornea. The results of both methods showed that the absence of collagen XIV significantly softens the cornea. Furthermore, the results showcase that both elastography techniques have the capability to distinguish the corneal stiffness of wild-type and collagen XIV– deficient (Col14a1–/–) murine corneas and provide complementary information regarding the mechanical properties of the corneal tissue. These results highlight the capabilities of these techniques to detect mechanical abnormalities, which may be useful for clinical detection of corneal disorders.