Velinsky S A, Bryant M R
Department of Mechanical Engineering, University of California, Davis 95616-5294.
Refract Corneal Surg. 1992 Mar-Apr;8(2):173-82.
Several recent papers have discussed the use of engineering-based computer methods for the analysis of keratorefractive surgical procedures. What has been lacking is a broader view of the role of engineering analysis in keratorefractive surgery. This article demonstrates how these various analysis methods can be coupled to provide a comprehensive methodology for the design of refractive surgical procedures.
A structural model of the eye, based on a linearly elastic, transversely isotropic finite element formulation is coupled to a full-eye optical model. The optical errors due to refractive keratotomy are estimated by ray tracing through the optical model and measuring the position of the resulting focal plane relative to the retina. Computer-based optimization methods are employed to determine the surgical parameters necessary to correct myopia for a given set of surgical design goals.
Results based on a hypothetical eye demonstrate agreement with clinical trends. Radial keratotomies are designed that eliminate refractive error while minimizing invasiveness in one case and maximizing the optical zone size in another. It is also shown that there is significant potential to customize this process on a patient-by-patient basis using clinically measured data.
We present an overview of the research necessary to bring this approach to fruition. While only a first step, the methodology presented in this article has the potential to increase the predictability of keratorefractive surgery by substantially increasing both the quality and the quantity of the information available to the refractive surgeon preoperatively.
最近有几篇论文讨论了使用基于工程学的计算机方法来分析角膜屈光手术过程。一直缺乏的是对工程学分析在角膜屈光手术中作用的更广泛视角。本文展示了如何将这些不同的分析方法结合起来，以提供一种用于屈光手术设计的综合方法。
基于线性弹性、横观各向同性有限元公式的眼睛结构模型与全眼光学模型相结合。通过光学模型进行光线追踪，并测量所得焦平面相对于视网膜的位置，以此估算屈光性角膜切开术引起的光学误差。采用基于计算机的优化方法来确定针对给定的一组手术设计目标矫正近视所需的手术参数。
基于假设眼睛的结果与临床趋势相符。设计了放射状角膜切开术，在一种情况下消除屈光不正的同时将侵入性降至最低，在另一种情况下则最大化光学区尺寸。还表明，利用临床测量数据逐患者定制此过程具有很大潜力。
我们概述了使这种方法实现所需的研究。虽然只是第一步，但本文提出的方法有可能通过大幅增加屈光外科医生术前可获得信息的质量和数量，提高角膜屈光手术的可预测性。
