Method for Assessing Local Mechanical Properties of the Cornea Based on Spectroscopic Magnetomotive Optical Coherence Elastography

Objective: Current methods for assessing corneal mechanical properties are limited, particularly in their ability to provide localized information. This study proposes a novel approach based on the spectroscopic magnetomotive optical coherence elastography (MM-OCE) technique, aiming to enable non-invasive, localized evaluation of corneal mechanical properties. Methods: Magnetic nanoparticles (MNPs) were distributed on sample surfaces to induce vibrations via magnetic excitation. A spectral-domain OCT system combined with phase-sensitive OCT analysis tracked mechanical responses. Gelatin phantoms (varying stiffness) and ex vivo porcine corneas (untreated vs. crosslinked [CXL] regions) were tested. MB-mode validated MNP-induced vibrations, while M-mode scans and spectral analysis determined resonance frequencies. Histology assessed tissue integrity post-MNP application. Results: Gelatin resonance frequencies increased with concentration, confirming sensitivity to mechanical variations. In corneas, MM-OCE detected significant differences between untreated and CXL-treated regions: resonance frequencies rose from 74.48 ± 6.23 Hz (untreated) to 83.42 ± 4.97 Hz (1-min UV), 110.92 ± 2.40 Hz (3-min UV), and 121.23 ± 3.02 Hz (6-min UV). Histology confirmed no MNP-induced tissue damage. Conclusion: MM-OCE effectively differentiates localized biomechanical changes in corneal tissue, demonstrating feasibility for quantifying stiffness variations induced by CXL. Significance: Although further improvements are needed for potential clinical applications, this study demonstrated that MM-OCE may offer a promising, non-invasive method for assessing local mechanical properties of a cornea, with the potential to enhance early diagnosis, treatment planning, and monitoring in ophthalmology.