Study On The Human Eye Optical Model And Optical Measuring Of Ocular Parameters By Interferometry

The human eye is a typical imaging instrument. The study of the eye optical model and optical measuring of ocular parameters by interferometry is always a popular topic in optics, optometry and ophthalmology.With the optical design software Zemax (Zemax Development Corp. San Diego, Calif.), the key optical models of eye model, including the corneal optical model with bi-conic surface, the lens gradient-index (GRIN) distribution model and chromatic dispersion models of ocular media are built. The lens GRIN model programmed in C language is loaded in Zemax. The chromatic dispersion models of ocular media represented by Conrady equations are built as a refractive index database to be called in Zemax. The measured data of ocular parameters are analyzed on normality test and the 95% confidence interval with statistical analysis software SPSS 13.0 (SPSS Inc., Chicago).A generic eye model and a personalized eye model based on Chinese population are built. The initial eye model is from the key optical models of eye model and statistical results of the measured data. In order to reproduce the measured eye aberrations at two pupil diameters (3mm & 6mm), the two optical systems with different pupil diameters are built simultaneously by the multi-configuration function in Zemax. The generic eye model is obtained with the reproduce precision (RMS errors) are 0.0712μm (pupil diameter=3mm) and 0.1675μm (pupil diameter=6mm) respectively. On the research of personalized eye model, the fidelity is improved by using complex surface type to express lens. And the RMS errors are 0.0089μm (pupil diameter=3mm) and 0.0098μm (pupil diameter=6mm) respectively.Based on the generic eye model, the applications of eye model are presented on corneal ablation model, the design of Intraocular Lens (IOL) and the supernormal vision model. The results show that the analyses based on eye models are comprehensive.The corneal topography and the intraocular distances measurements by interferometry are studied. The shearing interferometry is vibration insensitive. The lateral shearing interferometry and radial shearing interferometry with different phase-shifting methods are analyzed theoretically and experimentally. And the experimental system of cyclic radial shearing interferometry for corneal topography measurement is designed. The intraocular distances measurement based on Partial Coherence Interferometry (PCI) is discussed. The measurement principles of PCI and dispersion effects in PCI are analyzed. A simple experimental system based on PCI measurement is designed. And the measurement of glass slices with different thickness is presented.