The mechanical properties of the cornea in corneal ectasia disease undergo a significant reduction, yet the alterations in mechanical properties within distinct corneal regions remain unclear. In this study, we established a rabbit corneal ectasia model by employing collagenase II to degrade the corneal matrix within a central diameter of 6 mm. Optical coherence tomography was employed for the in vivo assessment of corneal morphology (corneal thickness and corneal curvature) one month after operation. Anisotropy and viscoelastic characteristics of corneal tissue were evaluated through biaxial and uniaxial testing, respectively. The results demonstrated a marked decrease in central corneal thickness, with no significant changes observed in corneal curvature. Under different strains, the elastic modulus of the cornea exhibited no significant differences in the up-down and naso-temporal directions between the control and model groups. However, the cornea in the model group displayed a significantly lower elastic modulus compared to the control group. Specifically, the elastic modulus of the central region cornea in the model group was significantly lower than that of the entire cornea within the same group. Moreover, in comparison to the control group, the cornea in the model group exhibited a significant increase in both creep rate and overall deformation rate. The instantaneous modulus and equilibrium modulus were significantly reduced in the model cornea. No significant differences were observed between the entire cornea and the central cornea concerning these parameters. The results indicate that corneal anisotropy remains unchanged in collagenase-induced ectatic cornea. However, a significant reduction in viscoelastic properties is noticed. This study provides valuable insights for investigating changes in corneal mechanical properties within different regions of ectatic corneal disease.
Parameters related to coagulation function are key clinical biomarker reflecting the coagulation status of the human blood system. The disorder of coagulation function could lead to multiple diseases such as hemophilia and ischemic stroke. Blood viscoelasticity can effectively characterize the rheological variations during blood coagulation, thus enabling comprehensive assessment of coagulation function. In this paper, electrowetting technology was adopted to develop the detection approach for blood viscoelasticity. A dynamic mathematical model of the detection system was established, and the core influencing factors of the detection system were deduced. The effects of critical parameters such as driving voltage, excitation frequency and dielectric layer thickness on detection performance were investigated systematically. The results indicate that the above parameters significantly affect the operating performance of the detection system. Optimized matching of system parameters can effectively improve the stability and detection accuracy of the system. Conclusively, the electrowetting based method achieves high-precision measurement of blood viscoelasticity, which provides a novel technical scheme for coagulation detection.