Eye and Vision · Jul 6, 2026

In vivo biomechanical property detection of the ciliary muscle based on optical coherence tomography and digital image correlation technology

By Wang J, Luo S, Li Y et al.

BACKGROUND: This study aimed to develop and validate a digital image correlation (DIC) methodology based on swept-source optical coherence tomography (SS-OCT) for quantifying in vivo ciliary muscle (CM) deformation and strain during accommodation. METHODS: This study was comprised of three phases. First, the measurement performance was examined across two SS-OCT systems (CASIA2 and VG200D) and four scanning modes (R1, R8, R16, and R64) by comparing the DIC-derived displacements with the simulated ground-truth fields. Second, reliability was validated using a "cross-image" strategy, in which artificial deformations were applied to biological images to assess tracking accuracy under realistic speckle noise. Third, 23 subjects were recruited and divided into three groups: control group (CN, n = 7), high myopia group (HM, n = 7), and elderly group (n = 9). Macroscopic morphological parameters (anterior CM length change and maximum CM thickness change) and biomechanical parameters (e.g., equivalent strain) were extracted synchronously. RESULTS: The R8 scanning mode in the CASIA2 device exhibited the most stable acquisition configuration. The robustness of the ncorr‑DIC algorithm was verified through the second-step experiment. Under the accommodative stimulus of - 5.0 D, the effective strain exhibited a highly significant graded attenuation among groups: CN (0.28 ± 0.06) > HM (0.20 ± 0.03) > Elderly (0.16 ± 0.05) (P = 0.002). Morphological changes were consistent with this finding, and CM thickening was significantly greater in the CN group than in the other two groups (P = 0.003). Combined analysis revealed that the mean effective strain was not only significantly positively correlated with macroscopic muscle thickening (r = 0.70, P < 0.001) but was also highly correlated with accommodation amplitude (r = 0.69, P < 0.001). CONCLUSION: DIC-based OCT analysis is feasible for assessing the biomechanical response of CM. By quantifying mechanical attenuation associated with HM and age-related decline, this method provides a new functional biomarker for investigating the mechanisms of accommodation dysfunction and guiding clinical interventions.

doi.org/10.1186/s40662-026-00498-wOpen accessPubMed 42402615Biomarkers