Mu Guoguang

A method to design aspheric spectacles for correction of high-order aberrations of human eye

Aiming at the correction of high-order aberrations of human eye with spectacles, a design method of aspheric spectacles is proposed based on the eye’s wavefront aberrations data. Regarding the eyeball and the spectacles as a whole system-the lens-eye system-the surface profiles of the spectacles are achieved by optimization procedure of lens design. Different from the conventional optometry, in which the refraction prescription is acquired with a visual chart, the design takes into account the two aspects of actual human viewing, eyeball rolling and certain distinct viewing field. The rotation angle of eyeball is set to be ±20° as wearing spectacles, and the field of view is set to be ±7° which is especially important as watching screen display. The individual eye model is constructed as the main part of the lens-eye system. The Liou eye model is modified by sticking a thin meniscus lens to the crystalline lens. Then the defocus of the individual eye is transferred to the front surface of the meniscus lens, and the astigmatism and high-order aberrations are transferred to the front surface of the cornea. 50 eyes are involved in this research, among which 36 eyes have good enough visual performance already after sphero-cylindrical correction. 10 eyes have distinct improvement in vision and 4 eyes have no visual improvement by further aspheric correction. 6 typical subject eyes are selected for the aberrations analysis and the spectacles design in this paper. It is shown that the validity of visual correction of aspheric lens depends on the characteristics of the eye’s wavefront aberrations, and it is effective for the eye with larger astigmatism or spherical aberration. Compared with sphero-cylindrical correction only, the superiority taken by the aspheric correction is mainly on the improvement of MTF at a larger field of view. For the best aspheric correction, the MTF values increase by 18.87%, 38.34%, 44.36%, 51.29% and 57.32% at the spatial frequencies of 40, 80, 100, 125 and 150 cycles/mm, respectively.

Correlation between Post-LASIK Starburst Symptom and Ocular Wavefront Aberrations

Monochromatic aberrations in post laser in-situ keratomileusis (LASIK) eyes are measured. The data are categorized into reference group and starburst group according to the visual symptoms. Statistic analysis has been made to find the correlation between the ocular wavefront aberrations and the starburst symptom. The rms aberrations of the 3rd and 4th orders for the starburst group are significantly larger than those for the reference group. The starburst symptom shows a strong correlation with vertical coma, total coma, spherical aberrations. For 3-mm pupil size and 5.8-mm pupil size, the modulation transfer function (MTF) of the starburst group are lower than those of the reference group, but their visual acuities are close. MTF and PSF analyses are made for two groups, and the results are consistent with the statistical analysis, which means the difference between the two groups is mainly due to the third- and fourth-order Zernike aberrations.

Optical study on the vision correction and supernormal vision based on the wave-front aberrations of human eye

In this paper we present the recent research results in the field of vision correction and supernormal vision according to the actual measurements of the wave-front aberrations and the corneal surface topography, the clinical detection of the visual function and the laser corneal refractive surgery, and the optimization of the optical system. These include the features of the aberrations of human eye with different pupil sizes, different fields of view and temporal accommodation, the influence of the polychromatic illumination of the visible wavelength on the supernormal vision, and the effect of the existing laser corneal refractive surgery on the wave-front aberrations of the eye. It is shown that the wave-front aberration of human eye is of temporal variation and of synthesis with multi impact factors. To achieve supernormal vision, an optimum engineering data for the customized laser corneal surgery should be firstly acquired, which may involve the dynamic free-form optical surface. Although the myopia can be corrected by the laser in situ keratomileusis (LASIK) in a certain degree, it brings about negative effects under scotopic conditions.

Pulsed digital holography for recording ultra-fast events

In this paper, spatially angular multiplexing technique in pulsed digital holography and an optical system based on this technique are introduced. Optical simulation and calculating analysis show that the designed system can be employed to record ultra-fast events of a time resolution in nanosecond.

Optical/digital color photography based on white-light information processing

The achievement in optical/digital color photography based on white-light information processing including the color-encoding camera, the color image decoder, the integral window Fourier algorithm of the Fourier transform in digital decoding, the color correction of the retrieval color image and the fusion of zero order diffraction is reported. This technique has found its important applications in the fields of aerial reconnaissance photography and far-distance ground photography due to its features of large information capacity, convenience in archival storage, the capability of color enhancement, particularly easy transportation by internet.

A New Technique For Pattern Recognition Using VFHF In White-Light Lensless Optical System

The advance in pattern recognition is achieved by the uses of Fresnel holographic filter (FHF) and extended source in a lensless correlator 1). This technique gains several advantages such as little effects of a displacement error in the alignment of the FRP and nonsensitivity to changes in scale and rotation of the detected object. In this paper, we present an improved technique by which the optical pattern recognition can be performed with white-light source and a volume Fresnel holographic filter (VFHF) in a lensless intensity correlator. The VFHF serves three functions: phase transformation, reconstructed wavelength selection as well as spatial filtering.