Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Petit Biotechnology Building (IBB), 315 Ferst Drive, Room 2306, Atlanta, GA 30332-0363, USA.
J R Soc Interface. 2022 Jul;19(192):20220108. doi: 10.1098/rsif.2022.0108. Epub 2022 Jul 6.
The iris is a muscular organ whose deformations can cause primary angle-closure glaucoma (PACG), a leading cause of blindness. PACG risk assessment does not consider iridial biomechanical factors, despite their expected influence on iris deformations. Here, we exploited an existing biometric dataset consisting of near-infrared movies acquired during the pupillary light reflex (PLR) as a unique resource to study iris biomechanics. The PLR caused significant (greater than 100%) and essentially spatially uniform radial strains in the iris , consistent with previous findings. Inverse finite-element modelling showed that sphincter muscle tractions were fivefold greater than iridial stroma stiffness (range 4- to 13-fold, depending on sphincter muscle size). This muscle traction is greater than has been previously estimated, which may be due to methodological differences and/or to different patient populations in our study (European descent) versus previous studies (Asian); the latter possibility is of particular interest due to differential incidence rates of PACG in these populations. Our methodology is fast and inexpensive and may be a useful tool in understanding biomechanical factors contributing to PACG.
虹膜是一种肌肉器官，其变形可导致原发性闭角型青光眼（PACG），这是失明的主要原因之一。PACG 风险评估并未考虑虹膜生物力学因素，尽管这些因素预计会对虹膜变形产生影响。在这里，我们利用现有的生物测量数据集，该数据集由瞳孔光反射（PLR）期间获得的近红外电影组成，作为研究虹膜生物力学的独特资源。PLR 导致虹膜的显著（大于 100%）且基本上空间均匀的径向应变，这与先前的发现一致。逆有限元建模表明，括约肌的牵引力比虹膜基质的硬度大五倍（范围为 4 到 13 倍，具体取决于括约肌的大小）。与之前的研究相比，这种肌肉牵引力比之前估计的要大，这可能是由于方法学差异以及我们研究中的患者群体（欧洲血统）与之前的研究（亚洲）不同；后者特别有趣，因为这些人群中 PACG 的发病率不同。我们的方法快速且廉价，可能是理解导致 PACG 的生物力学因素的有用工具。
