Atchison D A, Ye M, Bradley A, Collins M J, Zhang X, Rahman H A, Thibos L N
Centre for Eye Research, School of Optometry, Queensland University of Technology, Brisbane, Australia.
Optom Vis Sci. 1992 Oct;69(10):797-804. doi: 10.1097/00006324-199210000-00009.
Although diffractive contact lenses have been well documented in theory, no definitive experimental data have been reported which confirm that the near image is in fact created by diffraction rather than by refraction. We have tested the diffraction hypothesis for one type of diffractive contact lens (the Hydron Echelon bifocal) experimentally by measuring its longitudinal chromatic aberration in isolation and when worn on the eye. The basis of this test is that, according to theory, diffractive lenses should have chromatic aberration which is opposite in sign to that measured for the eye. Objective measurements of chromatic aberration were made with a focimeter when the lens was in a wet cell. Subjective measurements were made with a Badal optometer when the lens was worn on the eye. Four control experiments were conducted to provide baseline measurements of the eye's chromatic aberration, against which we compared the results obtained for the diffractive contact lens. The data were also compared with conventional measurements of refractive error obtained by standard subjective techniques and by an automated infrared refractor. Our results showed that the longitudinal chromatic aberration of the diffraction image of the Echelon bifocal lens was about one-half that obtained under the four control conditions: for the naked eye, for the nondiffraction image of the Echelon lens, or for either image of a refractive bifocal contact lens (CIBA Bisoft). These results are consistent with the theoretical prediction that the negative chromatic aberration of a diffractive contact lens should partially cancel the positive chromatic aberration of the human eye.(ABSTRACT TRUNCATED AT 250 WORDS)
尽管衍射隐形眼镜在理论上已有充分记载，但尚无确凿的实验数据证实近视力图像实际上是由衍射而非折射形成的。我们通过单独测量一种衍射隐形眼镜（Hydron Echelon双焦点隐形眼镜）的纵向色差以及佩戴在眼睛上时的纵向色差，对衍射假说进行了实验测试。该测试的依据是，根据理论，衍射透镜的色差符号应与眼睛测量的色差符号相反。当镜片置于湿盒中时，用焦度计对色差进行客观测量。当镜片佩戴在眼睛上时，用巴达尔验光仪进行主观测量。进行了四项对照实验，以提供眼睛色差的基线测量值，并以此为对照，比较衍射隐形眼镜的测量结果。还将这些数据与通过标准主观技术和自动红外验光仪获得的传统屈光不正测量值进行了比较。我们的结果表明，Echelon双焦点镜片衍射图像的纵向色差约为四种对照条件下获得的纵向色差的一半：裸眼、Echelon镜片的非衍射图像或折射双焦点隐形眼镜（CIBA Bisoft）的任一图像。这些结果与理论预测一致，即衍射隐形眼镜的负色差应部分抵消人眼的正色差。（摘要截短于250字）
