Aragón Institute of Engineering Research (i3A), University of Zaragoza, Spain.
Aragón Institute of Engineering Research (i3A), University of Zaragoza, Spain; Centro de Investigación Biomédica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), Spain.
Comput Methods Programs Biomed. 2022 Jun;221:106868. doi: 10.1016/j.cmpb.2022.106868. Epub 2022 May 11.
Although cataract surgery is a safe operation in developed countries, there is still room for improvement in terms of patient satisfaction. One of the key issues is assessing the biomechanical stability of the IOL within the capsular bag to avoid refractive errors that lead to a second surgery. For that purpose, a numerical model was developed to predict IOL position inside the capsular bag in the short- and long-term.
A finite element model containing the implanted IOL, the postcataract capsular bag, the zonules, and a portion of the ciliary body was designed. The C-loop hydrophobic LUCIA IOL was used to validate the numerical model and two more worldwide IOL designs were tested: the double C-loop hydrophobic POD FT IOL and the plate hydrophilic AT LISA IOL. To analyze the biomechanical stability in the long-term, the effect of the fusion footprint, which occurs days following cataract surgery, was simulated. Moreover, several scenarios were analyzed: the size and location of the capsulorexhis, the capsular bag diameter, the initial geometry of the capsular bag, and the material properties of the bag.
The biomechanical stability of the LUCIA IOL was simulated and successfully compared with the in vitro results. The plate AT LISA design deformed the capsular bag diameter up to 11.0 mm against 10.5 mm for the other designs. This design presented higher axial displacement and lower rotation, 0.19 mm and 0.2, than the C-loop design, 0.09 mm and 0.9.
All optomechanical biomarkers were optimal, assuring good optical performance of the three IOLs under investigation. Our findings showed that the capsulorexhis size influences the stiffness of the capsular bag; however, the shape in the anterior and posterior curvature surfaces of the bag barely affect. The results also suggested that the IOL is prone to mechanical perturbations with the fusion footprint, but they were not high enough to produce a significant refractive error. The proposed model could be a breakthrough in the selection of haptic design according to patient criteria.
尽管白内障手术在发达国家是一种安全的手术，但在患者满意度方面仍有改进的空间。其中一个关键问题是评估人工晶状体（IOL）在囊袋内的生物力学稳定性，以避免导致二次手术的屈光误差。为此，开发了一个数值模型来预测 IOL 在短时间和长时间内在囊袋内的位置。
设计了一个包含植入的 IOL、白内障囊袋、悬韧带和部分睫状体的有限元模型。使用 C 型疏水 LUCIA IOL 验证数值模型，并测试了另外两种全球范围内的 IOL 设计：双 C 型疏水 POD FT IOL 和板状亲水 AT LISA IOL。为了分析长期的生物力学稳定性，模拟了白内障手术后数天发生的融合足迹的影响。此外，还分析了几种情况：撕囊口的大小和位置、囊袋直径、囊袋的初始几何形状和囊袋的材料特性。
成功模拟了 LUCIA IOL 的生物力学稳定性，并与体外结果进行了比较。与其他设计相比，板状 AT LISA 设计使囊袋直径变形高达 11.0mm，而其他设计为 10.5mm。与 C 型环设计相比，该设计的轴向位移和旋转角度更高，分别为 0.19mm 和 0.2，而 C 型环设计分别为 0.09mm 和 0.9。
所有的光学生物力学标志物都是最优的，保证了三种研究中的 IOL 具有良好的光学性能。我们的研究结果表明，撕囊口的大小影响囊袋的刚度；然而，囊袋前、后表面的形状几乎没有影响。结果还表明，融合足迹会使 IOL 容易受到机械干扰，但这些干扰不足以产生显著的屈光误差。该模型可能是根据患者标准选择人工晶状体设计的突破。
