新型人工晶状体视觉仿生微机构设计方法及调焦机制研究

Replacing the physiological function of the crystalline lens by intraocular lens is the most effective method for cataract therapy. Due to the lack of accommodative lens power and decreasing gradually with the growth of time, the problem of 1000-degree hypermetropia after cataract surgery, that is serious presbyopia, is one of the burning issue. This project aims at proposing a novel method of mechanical design for vision bionics, and a novel cooperative focusing mechanism. The law of gradient index of the optic lens coupling with various materials, and its refractive focusing mechanism is studied. A multi-factor comprehensive analysis method of optic lens is established. The dimensional synthesis and focusing mechanism research of multistage amplified haptics are presented, after which the parametric configuration for micro-incision is generated. The micro parallel IOLs in the situation of dynamic balance and non-contact impact are manufactured. Through the research, the diopter can be enhanced from 3.5D to 10.0D, the incision can be declined from 12mm to 1.8-2.2mm, meanwhile, the long-term stability and security can be ensured. The present research has great significance in setting up a new generation of design theory and method of accommodative IOL with superior performance, which can radically revolutionize the presbyopia after cataract surgery.

采用人工晶状体（Intraocular Lens，简称IOL）替代人眼晶状体生理功能是治疗白内障的最有效手段，但目前IOL存在调节力不足、调节效果随时间增长而逐渐下降的缺陷，极易导致术后高达1000度远视，即严重老视问题。本项目旨在提出一种IOL视觉仿生机构设计新方法和协同调焦新机制：研究多材料耦合光学部梯度折射规律及其屈变调焦机理，建立光学部成像质量多指标综合分析方法；开展微切口适应多级运放襻结构及其参数化构型的尺度综合与调节机理研究；研制仿房水动态平衡和非接触冲击环境下的微尺度光-襻并联构型IOL。通过上述研究，可将屈光度从临床最大值3.5D提高到10.0D，手术创口由12mm减少至1.8-2.2mm，同时确保调节能力的长期稳定性和安全性。本项工作将建立新一代高性能可调节IOL的设计理论与方法，从根本上解决白内障术后老视问题。

光学部是保证IOL成像功能的核心部件。基于晶状体囊膜和核的直径、厚度、前后极点曲率半径为因变量，构建了多焦性解剖学精确人眼晶状体通用化模型（包括结构模型和调节模型），建立了梯度折射特征光学部层构模型，确定了各膜层最优折射率和最小厚度；研究了视远、视中、视近三种视场调节下的膜层折射率差值等变量与成像质量的映射关系，形成了光学部成像质量的多指标综合分析方法，确立了光学部屈变调焦新机制。.基于Gullstrand Ⅰ号模型眼结构参量，针对白内障超声术后常见并发症--囊袋皱缩综合征，建立了人眼二次曲面数学动态眼模型，用以调整眼模型参数及属性进而提高眼模型准确性。考虑囊袋皱缩综合征与撕囊直径大小、悬韧带张力以及IOL结构间的影响规律，通过描述人眼眼外肌几何特征，建立了差异化人眼-眼外肌有限元模型。基于囊袋周所综合征作用机制和影响，提出了基于杠杆式和桥式原理的新型四级柔性运放襻结构，考虑了柔性铰链转动中心偏移，获得睫状肌达到收缩极限时的运放有效增益可达19.3。.提出了IOL固液双相一体化成型工艺，构建了具有符合自然眼睫状肌-悬韧带-晶状体调节规律的IOL眼屈光调节实验系统；开展了基于全柔性襻结构的IOL眼的前置位移测量实验，包括焦距测试、分辨率测试和位移测试；研究了非接触冲击条件下接触面轮廓对系统动力行为的影响作用；验证了柔性微位移放大襻结构替代传统襻实现大幅度调节的可行性以及IOL光学部依靠自身弹性变形改变屈光度的有效性。.研究成果验证了位移调节高性能IOL设计新方法的可行性和可靠性，为其实现真正的临床推广奠定了坚实的基础。