Analysis of Accommodative Performance of a New Accommodative Intraocular Lens.

Purpose: To compare objective and subjective accommodation and visual acuities with a new accommodative intraocular lens (IOL) (Lumina; AkkoLens Clinical BV, Rijswijk, The Netherlands) with a monofocal IOL and young phakic eyes.

Methods: In this prospective, randomized controlled clinical investigation, patients aged 51 to 85 years with symptomatic cataract were enrolled in the study. A total of 25 eyes were implanted with the accommodative IOL and 18 eyes received the monofocal Acrysof SA60AT IOL (Alcon Laboratories, Inc.

Cramer-Rao bounds in functional form: theory and application to passive optical ranging.

A functional approach to the multivariate statistical model of a generalized incoherent passive optical ranging and imaging system with a CCD sensor is proposed. This approach implies that a large number of discrete, statistically independent, random data (pixel readouts) can be approximated by a continuous random function. Thus, the joint probability density function (PDF) takes a functional form; the statistical averages of the infinite-variate PDF and the Fisher information become functional integrals that can be treated analytically in the Gaussian approximation.

Passive ranging and three-dimensional imaging through chiral phase coding.

We present a method for single-image passive ranging and three-dimensional (3D) imaging in incoherent light based on chiral phase coding. A chiral linear phase variation across the aperture of an optical system results in a frequency response with a characteristic pattern of fringes such that the spatial period and inclination of the pattern depend on the focusing error. From this dependency, the absolute focusing error and, hence, the distance to the object can be found.

Asymptotic behavior of the spatial frequency response of an optical system with defocus and spherical aberration.

Asymptotic expressions are derived for the two-dimensional incoherent optical transfer function (OTF) of an optical system with defocus and spherical aberration. The two-dimensional stationary phase method is used to evaluate the aberrated OTF at large and moderately large defocus and spherical aberration. For small aberrations, the OTF is approximated by a power series in the aberration coefficients.

Sharp-focus image restoration from defocused images.

We present a noniterative algorithm for sharp-focus image restoration from multiple defocused images having known relative defocus values between the image planes but unknown absolute defocus values with respect to the in-focus plane. Starting from an arbitrary value of defocus relative to the in-focus plane and using the optical transfer function, the algorithm evaluates the absolute defocus and retrieves the in-focus image of an incoherently illuminated planar object. Experiments with a circular-aperture imaging system confirm the efficiency and robustness of the algorithm.

Optical system invariant to second-order aberrations.

An approximate analytical expression is derived for the two-dimensional incoherent optical transfer function (OTF) of an imaging system invariant to second-order aberrations. The system broadband behavior resulting from a third-order phase mask in its pupil plane is analyzed by using the two-dimensional stationary phase method. This approach does not require mathematical separability of the pupil function and can be applied to any pupil shape.

Stretchable diffraction gratings for spectrometry.

We have investigated the possibility of using transparent stretchable diffraction gratings for spectrometric applications. The gratings were fabricated by replication of a triangular-groove master into a transparent viscoelastic. The sample length, and hence the spatial period, can be reversibly changed by mechanical stretching.

Liquid-crystal intraocular adaptive lens with wireless control.

We present a prototype of an adaptive intraocular lens based on a modal liquid-crystal spatial phase modulator with wireless control. The modal corrector consists of a nematic liquid-crystal layer sandwiched between two glass substrates with transparent low- and high-ohmic electrodes, respectively. Adaptive correction of ocular aberrations is achieved by changing the amplitude and the frequency of the applied control voltage.

Cubic optical elements for an accommodative intraocular lens.

We present a new accommodative intraocular lens based on a two-element varifocal Alvarez lens. The intraocular lens consists of (1) an anterior element combining a spherical lens for refractive power with a cubic surface for the varifocal effect, and (2) a posterior element with a cubic surface only. The focal length of the IOL lens changes when the superimposed refractive elements shift in opposite directions in a plane perpendicular to the optical axis.