Different schematic eyes and their accuracy to the in vivo eye: A quantitative comparison study
Different schematic eyes and their accuracy to the in vivo eye: A quantitative comparison study
复制标题
DOI：
10.1590/s0103-97332007000300008
复制
发表时间：
2007-06-01
影响因子：
1.6
通讯作者：
Carvalho, Luis Alberto
中科院分区：
文献类型：
--
作者：
de Almeida, Marina Storani;Carvalho, Luis Alberto
目前的眼科技术允许以相当高的精确度和定制化操作人眼的眼睛组件，如前房角膜和晶状体。这项技术为利用眼睛的某些特性来改进矫正光学像差的方法开辟了可能性。此外，眼部护理专业人员的产品开发和研究已经达到了非常高的标准，因为现在有软件可以设计和实际模拟产品的任何机械或光学特性，甚至在产品投入生产线之前。虽然在一般形式上非常相似，但不同的人眼模型通过考虑眼睛结构的组成元素(如折射率和表面曲率)中的不同属性组合来模拟图像形成，产生非常类似于生物眼睛的视网膜图像。利用光学设计软件，对文献中已有的5种常见的示意图进行了模拟。这些模型是Helmholtz-Laurance、Gullstrand、Emsley、Greivenkamp和Liou&Brennan。使用不同的定量光学质量参数比较了这些不同模型的光学性能。Liou和Brennan的模型包含了以前的模型中没有考虑的生物眼睛的特征，如梯度折射率的分布和偏心的瞳孔。此外，它具有很高的可靠性，因为它考虑了活体眼睛经验测量的平均值，以定义角膜的大小和参数，如角膜前后曲率、晶状体、眼轴长度等。MTF(调制传递函数)、SPOT图和光线扇之间的比较显示了不同眼睛模型之间的图像质量差异，Strehl比率也被用作比较参数。不同模型之间的仔细比较显示，前四个示意图眼的光学质量比一般健康的活体正视眼的预期光学质量更好。刘和布伦南的示意图眼睛是与活体生物眼睛最相似的眼睛。因此，在定制视力矫正的研究或产品开发等应用中，必须考虑生物眼睛固有的光学特性，我们建议使用后一种模型；对于不需要屈光限制性能的应用，大多数其他模型应该是一个很好的近似值。
Current ophthalmic technology allows the manipulation of eye components, such as anterior comea and lens, of the human eye with a considerable precision and customization. This technology opens up the possibility of exploiting some characteristics of the eye in order to improve the methods of correcting optical aberrations. Moreover, product development and research for the eye-care professional has reached very high standards, since there is nowadays software available to design and simulate practically any mechanical or optical characteristic of the product, even before it is thrown into production line. Although quite similar in the general form, different human eye models simulate the image formation by considering different property combinations in the constitutive elements of the eye structure (such as refraction index and surface curvatures), producing retinal images that resemble very closely those of the biological eye. Using optical design software, we have implemented a simulation of 5 well-known schematic eyes available in the literature. These models were the Helmholtz-Laurance, Gullstrand, Emsley, Greivenkamp and Liou & Brennan. The optical performance of these different models was compared using different quantitative optical quality parameters. The model of Liou and Brennan, contains features of the biological eye that were not considered in previous models, as the distribution of a gradient refraction index and a decentered pupil. Furthermore, it has great reliability since it takes into account the mean value of empirical measurements of the in vivo eye in order to define size and parameters such as anterior and posterior curvature of comea, lens, axial length, etc. Comparisons between the MTF (Modulation Transfer Function), spot diagrams and ray fan showed the difference in image quality between eye models, and the Strehl Ratio was also used as a parameter of comparison. A careful comparison between the different models showed that the first four schematic eyes have better optical quality than what is expected for the general and healthy emmetropic in vivo eye. Liou and Brennan schematic eye is the one that most closely resembles the in vivo biological eye. Therefore, in applications, such as research or product development for customized vision correction, which must consider optical properties intrinsic to the biological eye, we recommend this latter model; for applications that do not require refraction-limited performance, most of the other models should be a good approximation.