Laboratory of Experimental Optometry, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
Sci Rep. 2017 Nov 2;7(1):14974. doi: 10.1038/s41598-017-14750-w.
Currently available clinical devices are unable to measure corneal biomechanics other than at the central region. Corneal stiffness (S), thickness, and radius of curvature was measured at the central cornea (primary fixation) and 3 mm from the temporal limbus (primary and nasal fixations). The corneal tangent modulus (E) of 25 healthy subjects was calculated from these data. After confirming normality, repeated measures analysis of variance (RMANOVA) revealed significant difference in S (F(2, 48) = 21.36, p < 0.001) at different corneal regions and direction of fixations. E also varied significantly at different corneal regions and direction of fixations (RMANOVA: F(2, 48) = 23.06, p < 0.001). A higher S and a lower E were observed at the temporal region compared with the corneal centre. Nasal fixation further increased S and E values compared with primary fixation. Due to the specific arrangement of corneal collagen fibrils, heterogeneity of corneal biomechanical properties is expected. In future clinical practice, localized corneal biomechanical alternation and measurement might assist corneal disease detection and post-surgery management. In addition, practitioners should be aware of the fixation effect on corneal biomechanical measurement.
目前的临床设备只能测量中央区域的角膜生物力学，无法测量其他区域。本研究在角膜中央（主固视）和 3mm 颞侧角膜缘（主固视和鼻侧固视）处测量角膜硬度（S）、厚度和曲率半径。从这些数据中计算 25 名健康受试者的角膜切线模数（E）。在确认正态性后，重复测量方差分析（RMANOVA）显示不同角膜区域和固视方向的 S（F（2，48）= 21.36，p < 0.001）存在显著差异。E 也在不同的角膜区域和固视方向上有显著差异（RMANOVA：F（2，48）= 23.06，p < 0.001）。与角膜中央相比，颞侧区域的 S 和 E 值更高。与主固视相比，鼻侧固视进一步增加了 S 和 E 值。由于角膜胶原纤维的特定排列，角膜生物力学特性存在异质性。在未来的临床实践中，局部角膜生物力学变化和测量可能有助于角膜疾病的检测和术后管理。此外，临床医生应注意固视对角膜生物力学测量的影响。
