Patel S, Marshall J, Fitzke F W
Department of Vision Science, Glasgow Caledonian University, Scotland, UK.
Refract Corneal Surg. 1993 Sep-Oct;9(5):366-75.
Predicting the outcome of refractive surgical procedures is one of the chief goals of the refractive surgeon. Besides perfecting the change required to nullify a refractive error, the optical quality of the postsurgical eye should be maximized.
A model eye useful for predicting the likely effects on the optical performance of the eye as a result of refractive surgical intervention is presented. The model features aspheric ocular interfaces, a gradient refractive index within the lens, and a uni-index cornea. The dimensions of the model parameters are taken from the literature. Baker's method of ray tracing through aspheric surfaces is used to predict the lateral spherical aberration of the eye for specific pupil sizes. The results for various operational conditions such as number of lens layers and corneal shape were calculated.
The model predicts that optimal optical imagery is produced when the corneal profile is represented by a flattening ellipse (shape factor = .65 to .85). Ideally, in refractive surgery involving the cornea, the postoperative corneal contour should conform to this flattening ellipse.
预测屈光手术的结果是屈光外科医生的主要目标之一。除了完善消除屈光不正所需的改变外，术后眼睛的光学质量也应最大化。
提出了一个用于预测屈光手术干预对眼睛光学性能可能影响的模型眼。该模型具有非球面眼界面、晶状体内部的渐变折射率和单折射率角膜。模型参数的尺寸取自文献。采用贝克通过非球面表面进行光线追踪的方法来预测特定瞳孔大小下眼睛的横向球差。计算了各种操作条件下的结果，如晶状体层数和角膜形状。
该模型预测，当角膜轮廓由扁平椭圆表示时（形状因子 = 0.65 至 0.85），会产生最佳光学成像。理想情况下，在涉及角膜的屈光手术中，术后角膜轮廓应符合此扁平椭圆。
