Extended-depth-of-focus wavefront design from pseudo-umbilical space curves.

Designing extended-depth-of-focus wavefronts is required in multiple optical applications. Caustic location and structure analysis offer a powerful tool for designing such wavefronts. An intrinsic limitation of designing extended-depth-of-focus wavefronts is that any smooth surface, with a non-constant mean curvature, unavoidably introduces a separation between caustic sheets, which is proportional to the ratio of change of the mean curvature along a curve embedded in the wavefront.

Integrated analysis of industrial limitations and image quality: an end-to-end design approach.

There is a trend in optical system design toward explicitly considering real-world industrial demands in the metrics to be optimized, from which emerges a cost-performance trade-off. Another relevant recent tendency is the so-called end-to-end design, where the design metric is an expected quality index of the final image, after digital restoration. We propose an integrated approach for analyzing the cost-performance trade-off in end-to-end designs.

Robust numerical solution to the Levi-Civita wavefront coupling problem via level set computation of the point characteristic function.

The Levi-Civita wavefront coupling problem consists of, given two prescribed wavefronts, obtaining a refractive or reflective surface coupling them. We propose a robust numerical method to solve Levi-Civita's problem, whose rationale is to consider that Levi-Civita's solutions are level surfaces of the point characteristic function established between points of incoming and outgoing wavefronts. The method obtains both surface data points and their normals, enabling a more robust surface reconstruction.

Catastrophe optics theory unveils the localised wave aberration features that generate ghost images.

Monocular polyplopia (ghost or multiple images) is a serious visual impediment for some people who report seeing two (diplopia), three (triplopia) or even more images. Polyplopia is expected to appear if the point spread function (PSF) has multiple intensity cores (a dense concentration of a large portion of the radiant flux contained in the PSF) relatively separated from each other, each of which contributes to a distinct image. We present a theory that assigns these multiple PSF cores to specific features of aberrated wavefronts, thereby accounting optically for the perceptual phenomenon of monocular polyplopia.

Multifocal wavefronts with prescribed caustics in axially symmetric optical systems.

Multifocal and/or extended depth-of-focus designs are widely used in many optical applications. In most of them, the optical configuration has axial symmetry. A usual design strategy consists of exploring the optimal wavefronts that emerging out of the optical system would provide the desired multifocal properties.

Smooth multifocal wavefronts with a prescribed mean curvature for visual optics applications.

Multifocal lenses comprising progressive power surfaces are commonly used in contact and intraocular lens designs. Given a visual performance metric, a wavefront engineering approach to design such lenses is based on searching for the optimal wavefront at the exit pupil of the eye. Multifocal wavefronts distribute the energy along the different foci thanks to having a varying mean curvature.

Admissible surfaces in progressive addition lenses.

Progressive addition lenses (PALs) contain a surface of spatially varying curvature, which supplies variable optical power for different viewing areas over the lens. We derive complete compatibility equations providing the exact magnitude of a cylinder along lines of curvature on any arbitrary PAL smooth surface. These equations reveal that, contrary to current knowledge, the cylinder and its derivative depend not only on the principal curvature and its derivatives along the principal line but also on the geodesic curvature and its derivatives along the line orthogonal to the principal line.

Clinicopathologic findings of naturally occurring Rabbit Hemorrhagic Disease Virus 2 infection in pet rabbits.

Two pet rabbits were presented with an acute decrease in appetite and activity. Rabbit 1 showed severe hypothermia, bradycardia, arrhythmias, a heart murmur, dyspnea, occlusion of the nares with secretions, icterus, dehydration, and gaseous gastrointestinal dilation. The urine was dark yellow.

Foveal vision power errors induced by spectacle lenses designed to correct peripheral refractive errors.

Purpose: Radial Refractive Gradient (RRG) spectacles are lenses specifically designed to minimize peripheral hyperopic defocus typically found in conventional spectacles. Our goals were: (1) to demonstrate a method to design such lenses; and (2) to quantify the exact foveal vision power errors induced by them.

Methods: The design procedure was based on a point-by-point sequential surface construction algorithm that designs a front aspheric surface (back surface is spherical) to achieve a given overall tangential focal length of the lens.

Simulating real-world scenes viewed through ophthalmic lenses.

We present a comprehensive procedure to simulate real-world scenes viewed through ophthalmic lenses. Such a method enables us to anticipate the effects on image formation of the following combined undesired optical defects typically found in ophthalmic lenses: blur, distortion, and chromatic aberration. Additionally, it helps in comparing the expected scenes seen with different lens designs.

The relationship between dioptric power and magnification in progressive addition lenses.

Purpose: Non-uniform magnification (distortion) and dioptric blur are two major undesired optical defects affecting vision when looking through progressive addition lenses (PALs) and studying them is potentially very valuable for PAL design. The major purpose of this paper is to analyse the relationship between dioptric power and magnification and, additionally, to evaluate the expected values of distortion and dioptric blur typically present in PALs. This has not been carefully and rigorously analysed to date.

Geometrical interpretation of dioptric blurring and magnification in ophthalmic lenses.

Blur and non-uniform magnification are two related undesired effects affecting vision when looking through eyeglasses. We propose a geometrical framework to study the relationship between both effects. Magnification and blur are locally characterized by dioptric and magnification matrices, respectively, which we compute here by using a novel two-ray numerical method.

The concept of geodesic curvature applied to optical surfaces.

Purpose: To propose geodesic curvature as a metric to characterise how an optical surface locally differs from axial symmetry. To derive equations to evaluate geodesic curvatures of arbitrary surfaces expressed in polar coordinates.

Methods: The concept of geodesic curvature is explained in detail as compared to other curvature-based metrics.

Wavefront reconstruction from tangential and sagittal curvature.

In a previous contribution [Appl. Opt.51, 8599 (2012)], a coauthor of this work presented a method for reconstructing the wavefront aberration from tangential refractive power data measured using dynamic skiascopy.

Multifocal intraocular lens providing optimized through-focus performance.

A widespread type of multifocal intraocular lens (MIOL) is based on expanding the depth of focus with specific amounts of spherical aberration. However, knowing the optimal wavefront aberration for multifocality does not directly provide a MIOL geometry. To overcome this issue, we present a new strategy to design MIOLs.

An ancient explanation of presbyopia based on binocular vision.

Presbyopia, understood as the age-related loss of ability to clearly see near objects, was known to ancient Greeks. However, few references to it can be found in ancient manuscripts. A relevant discussion on presbyopia appears in a book called Symposiacs written by Lucius Mestrius Plutarchus around 100 A.

Wavefront aberration reconstruction from tangential refractive powers measured with spatial dynamic skiascopy.

The aim of this work was to study, using numerical simulations, the attainable level of accuracy to reconstruct the wavefront aberrations from tangential refractive power data measured with dynamic skiascopy. Two mathematical methods have been implemented. The first one is based on curve integration of the curvature data, previously interpolated with cubic splines.

Accuracy of the reconstruction of the crystalline lens gradient index with optimization methods from ray tracing and Optical Coherence Tomography data.

The accuracy of the reconstruction of the Gradient Refractive Index (GRIN) of the crystalline lens from optimization methods was evaluated. Different input data, including direction cosines of deflected rays, ray impacts obtained from ray tracing and optical path differences from Optical Coherence Tomography (OCT) were studied. Three different GRIN models were analyzed.

Mechanical design of a power-adjustable spectacle lens frame.

Power-adjustable spectacle lenses, based on the Alvarez-Lohmann principle, can be used to provide affordable spectacles for subjective refractive errors measurement and its correction. A new mechanical frame has been designed to maximize the advantages of this technology. The design includes a mechanism to match the interpupillary distance with that of the optical centers of the lenses.

Design of isoplanatic aspheric monofocal intraocular lenses.

A new and complete methodology of monofocal intraocular lens (IOL) design is presented aiming at isoplanatism, i.e. IOLs that provide the eye with optimized optical quality over a wide field of view (typically in a range of ten degrees).

The Alvarez and Lohmann refractive lenses revisited.

Alvarez and Lohmann lenses are variable focus optical devices based on lateral shifts of two lenses with cubic-type surfaces. I analyzed the optical performance of these types of lenses computing the first order optical properties (applying wavefront refraction and propagation) without the restriction of the thin lens approximation, and the spot diagram using a ray tracing algorithm. I proposed an analytic and numerical method to select the most optimum coefficients and the specific configuration of these lenses.

Analysis of the optical field on the human retina from wavefront aberration data.

Wave aberrations in the human eye are usually known with respect to the ideal spherical wavefront in the exit pupil. Using Kirchhoff's diffraction theory, we have derived a diffraction integral to compute the optical field on the retina from the wave aberration data. We have proposed a numerical algorithm based on the Stamnes-Spjelkavik-Pedersen (SSP) method to solve that integral.

Balance of corneal horizontal coma by internal optics in eyes with intraocular artificial lenses: evidence of a passive mechanism.

It is well known that the aberrations of the cornea are partially compensated by the aberrations of the internal optics of the eye (primarily the crystalline lens) in young subjects. This effect has been found not only for the spherical aberration, but also for horizontal coma. It has been debated whether the compensation of horizontal coma is the result of passive mechanism [Artal, P.

Analytical tools for customized design of monofocal intraocular lenses.

We propose a complete methodology to develop custom monofocal Intraocular Lens (IOL) designs and evaluate their performance on-axis based on an analytical formulation. The analytical formulation was based on Gaussian and primary aberration theory applied to custom (individual biometric data) and realistic (multilayer cornea and thick IOL) pseudoaphakic eye models. Gradient-based optimization algorithms were performed to search for optimal designs.