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Purpose: Investigations into the correction of presbyopia have considered lens design, clinical implications and the development of objective metrics such as the visual Strehl ratio. This study investigated the Jacobi–Fourier phase mask as an ophthalmic element in the correction of presbyopia. The goal was to develop a contact or intraocular lens whose performance was largely insensitive to changes in pupil diameter. Methods: Numerical simulations based on Fourier optics were performed to evaluate three different Jacobi–Fourier polynomials, with the aim of providing a range of clear vision (1 Dioptre (D)). Performance was evaluated for three pupil sizes (6, 4 and 2 mm), while polychromatic images were simulated using three different wavelengths (656.3, 587.6 and 486.1 nm). The Neural Transfer function was included in the simulation. To validate the method and results, we used the Visual Strehl combined objective metric (VSCombined) currently used in visual optics. This metric gives more weight to the phase transfer function and is more suitable for non‐symmetrical phase functions. Results: Numerical validation showed the suitability of the Jacobi–Fourier phase masks for extending the range of clear vision of presbyopic eyes, providing a visual acuity of at least 0.10 logMAR (6/7.5 Snellen) at all distances between 1 and 6 m. The results show a range of clear vision of 1D was not affected by changes in pupil size, an increase in retinal image contrast accompanied by image artefact reduction by increasing the radial order of the Jacobi–Fourier phase mask and a reduction of wavelength dependence of the retinal images. These results are supported by simulated images and the objective criterion VSCombined. Conclusions: The use of Jacobi–Fourier phase masks as ophthalmic elements for presbyopic correction show promising results, with a good range of clear vision and reduced dependence on pupil size and chromatic aberration. [ABSTRACT FROM AUTHOR]

A dual setup composed of a point diffraction interferometer (PDI) and a Hartmann--Shack (HS) wavefront sensor was built to compare the estimates of wavefront aberrations provided by the two different and complementary techniques when applied to different phase plates. Results show that under the same experimental and fitting conditions both techniques provide similar information concerning the wavefront aberration map. When taking into account all Zernike terms up to 6th order, the maximum difference in root-mean-square wavefront error was 0.08 [micro]m, and this reduced up to 0.03 [micro]m when excluding lower-order terms. The effects of the pupil size and the order of the Zernike expansion used to reconstruct the wavefront were evaluated. The combination of the two techniques can accurately measure complicated phase profiles, combining the robustness of the HS and the higher resolution and dynamic range of the PDI. [c] 2010 Optical Society of America OCIS codes: 080.1010, 120.3180, 120.4630, 130.6010.

Problems stemming from quantitative phase imaging from intensity measurements play a key role in many fields of physics. Techniques based on the transport of intensity equation require an estimate of the axial derivative of the intensity to invert the problem. Derivation formulas in two adjacent planes are commonly used to experimentally compute the derivative of the irradiance. Here we propose a formula that improves the estimate of the derivative by using a higher number of planes and taking the noisy nature of the measurements into account. We also establish an upper and lower limit for the estimate error and provide the distance between planes that optimizes the estimate of the derivative. OCIS codes: 100.5070, 110.0180, 110.7440, 000.3860.

Eye fundus images are used in clinical diagnosis for the detection and assessment of retinal disorders. When retinal images are degraded by scattering due to opacities of the eye tissues, the precise detection of abnormalities is complicated depending on the grading of the opacity. This paper presents a concept proof study on the use of the contrast limited adaptive histogram equalization (CLAHE) technique for better visualization of eye fundus images for different levels of blurring due to different stages of cataracts. Processing is performed in three different color spaces: RGB, CIELAB and HSV, with the aim of finding which one better enhances the missed diagnostic features due to blur. The experimental results show that some fundus features not observable by naked eye can be detected in some of the space color processed with the proposed method. In this work, we also develop and provide an online image process, which allows clinicians to tune the default parameters of the algorithm for a better visualization of the characteristics of fundus images. It also allows the choice of a region of interest (ROI) within the images that provide better visualization of some features than those enhanced by the processing of the full picture. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has posed distinctive challenges to adolescents and young adults living with spina bifida, especially those from ethic minority populations. With this public health challenge in mind, developing a customized electronic health record to leverage registry data to promote and quantify COVID-19 vaccination uptake among this population is feasible. We provide a brief description of our activities in customizing an electronic health record to track vaccination uptake among adolescents and young adults with spina bifida (AYASB); and the lessons learned, in hopeful support of those scaling-up vaccination delivery across the globe for AYASB as they transition to adult-centered care. Thus, as providers think globally and act locally, COVID-19 immunization efforts can be implemented while providing culturally appropriate transition policies and services for individuals with neurodevelopmental disabilities. [ABSTRACT FROM AUTHOR]

Wavefront coding is a hybrid optical–digital technique proposed to increase the effective depth of focus of optical systems. The key to wavefront coding lies in the design of a suitable phase mask placed at the system's aperture to achieve invariant imaging properties over a range of defocus. In systems limited by temporally or spatially varying aberrations the use of wavefront coding has not yet been demonstrated. Here, we propose the use of Jacobi–Fourier shaped phase masks to produce sharp and clear images for optical systems affected by random and varying aberrations. When choosing the mask, noise levels must be taken into account too. In order to illustrate the potential use of the masks we will show by experimental simulations that a Jacobi–Fourier mask can be designed to alleviate temporally varying aberrations due to atmospheric turbulences being robust to noise while keeping acceptable resolution and reducing image artifacts. [ABSTRACT FROM AUTHOR]

Wavefront coding (WFC) is an optical-digital technique that consists in introducing a suitable phase mask (PM) in the aperture plane able to extent, after image processing, the depth of field of an optical system. The key to WFC lies in the shape of the PMs to achieve the invariant imaging properties over the range of defocus. Cubic PM was the first proposed. Next, trefoil mask avoided periodic artifacts in the images keeping the goal of depth extension. The performance of the masks, resolution and noise of the coded images, depends on their strength, required range of defocus and f-number of the optical system. Here, we will provide the experiments that will support that a member of the Jacobi–Fourier phase masks can be chosen depending on the f-number of the optical system to get the best balance between resolution, noise level and artifact presences while keeping depth of focus. [ABSTRACT FROM AUTHOR]

We aimed to evaluate the association of aortic and brachial short-term blood pressure variability (BPV) with the presence of target organ damage (TOD) in hypertensive patients. One-hundred seventy-eight patients, aged 57 ± 12 years, 33% women were studied. TOD was defined by the presence of left ventricular hypertrophy on echocardiogram, microalbuminuria, reduced glomerular filtration rate, or increased aortic pulse wave velocity. Aortic and brachial BPV was assessed by 24-hour ambulatory BP monitoring (Mobil-O-Graph). TOD was present in 92 patients (51.7%). Compared to those without evidence of TOD, they had increased night-to-day ratios of systolic and diastolic BP (both aortic and brachial) and heart rate. They also had significant increased systolic BPV, as measured by both aortic and brachial daytime and 24-hours standard deviations and coefficients of variation, as well as for average real variability. Circadian patterns and short-term variability measures were very similar for aortic and brachial BP. We conclude that BPV is increased in hypertensive-related TOD. Aortic BPV does not add relevant information in comparison to brachial BPV. [ABSTRACT FROM AUTHOR]

Presbyopia correction involves different types of studies such as lens design, clinical study, and the development of objective metrics, such as the visual Strehl ratio. Different contact lens designs have been proposed for presbyopia correction, but performance depends on pupil diameter. We will analyze the potential use of a nonsymmetrical element, a cubic phase mask (CPM) solution, to develop a contact or intraocular lens whose performance is nearly insensitive to changes in pupil diameter. We will show the through focus optical transfer function of the proposed element for different pupil diameters ranging from 3 to 7 mm. Additionally, we will show the images obtained through computation and experiment for a group of eye charts with different visual acuities. Our results show that a CPM shaped as 7.07 µm * (Z3³ - Z3-3) - 0.9 µm Z20 is a good solution for a range of clear vision with a visual acuity of at least 0.1 logMar from 0.4 to 6 m for pupil diameters in the 3- to 7-mm range. Our results appear to be a good starting point for further development and study of this kind of CPM solution for presbyopia. [ABSTRACT FROM AUTHOR]

During infections with protozoan parasites or some viruses, T cell immunosuppression is generated simultaneously with a high B cell activation. It has been described that, as well as producing antibodies, plasmablasts, the differentiation product of activated B cells, can condition the development of protective immunity in infections. Here, we show that, in T. cruzi infection, all the plasmablasts detected during the acute phase of the infection had higher surface expression of PD-L1 than other mononuclear cells. PD-L1 hi plasmablasts were induced in vivo in a BCR-specific manner and required help from Bcl-6 + CD4 + T cells. PD-L1 hi expression was not a characteristic of all antibody-secreting cells since plasma cells found during the chronic phase of infection expressed PD-L1 but at lower levels. PD-L1 hi plasmablasts were also present in mice infected with Plasmodium or with lymphocytic choriomeningitis virus, but not in mice with autoimmune disorders or immunized with T cell-dependent antigens. In vitro experiments showed that PD-L1 hi plasmablasts suppressed the T cell response, partially via PD-L1. Thus, this study reveals that extrafollicular PD-L1 hi plasmablasts, whose peaks of response precede the peak of germinal center response, may have a modulatory function in infections, thus influencing T cell response., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Serrán, Vernengo, Almada, Beccaria, Gazzoni, Canete, Roco, Boari, Ramello, Wehrens, Cai, Zuniga, Montes, Cockburn, Rodriguez, Vinuesa and Gruppi.)

Wavefront coding is a technique that combines optical phase elements and digital signal processing in order to increase the effective depth of focus of optical systems. The success of wavefront coding lies in the design of a suitable phase mask placed at the system's aperture. This element allows for image formation invariant under the effects of different second-order optical aberrations. In optical systems limited by temporally or spatially varying high-order aberrations, the use of wavefront coding has not been fully demonstrated. Here we propose the choice of Jacobi-Fourier shaped phase masks to produce sharp and clear retinal images of living eyes. To demonstrate the potential use of the technique, we analyze the performance of the Jacobi-Fourier phase masks through experimental simulations to alleviate aberrations for different eye aberrations. We will show that the best mask choice is robust to noise while keeping acceptable resolution and reducing image artefacts.

The concept of curvature sensing is reviewed, and a comprehensive derivation of the curvature polynomials is given, whose inner products with the wavefront curvature data yield the Zernike aberration coefficients of an aberrated circular wavefront. The data consist of the Laplacian of the wavefront across its interior and its outward normal slope at its circular boundary. However, we show that the radial part of the curvature polynomials and their slopes at the boundary of the wavefront have a value of zero, except when the angular frequency of the corresponding Zernike polynomial is equal to its radial degree. As a result, the effect of noise on the corresponding Zernike coefficients is lower because the noisy data at the boundary of the wavefront is not used to determine their values. The use of the curvature polynomials to determine the Zernike coefficients is demonstrated with simulated noisy curvature data of an aberration function consisting of 10 Zernike coefficients, namely defocus, primary, secondary, and tertiary astigmatism, coma, and spherical aberrations.

We show that spherical aberration of all orders can be generated as an extrinsic aberration in a system of axially translating plates. Some practical examples are provided. In particular for two phase plates that are 10 mm in diameter it is possible to generate from -10 to 10 waves of fourth-order spherical aberration with an axial displacement of +/- 0.65 mm. We also apply the phenomenon of extrinsic aberration for the generation of a conical wavefront and other non-axially symmetric wavefronts, in other words we propose what can be called a generalized zoom plate.

Work remains to be done to understand the origins of ocular aberrations. We analyze lens aberrations of several species with Y-suture branches (bovine, ovine, and porcine) and their relationship with suture distribution. Aberrations are measured in vitro with a point diffraction interferometer in 10 different eyes of each species. The minimum number of Zernike polynomials minimizing the root mean square error of the wavefront is estimated by processing the interferograms. Through this we find significant amounts of astigmatism, coma, spherical aberration, and trefoil in the lenses of the three species. Moreover, we observe a high degree of correlation between the orientation of the lens sutures and the axis of nonrotationally symmetric aberrations. Our results point to lens sutures as the histological origin of the most significant lens aberrations: astigmatism, coma, and trefoil, but we are unable to find a major suture governing all the axes.

Purpose: Design a device for accurate measurements of local optical properties of progressive addition lenses (PALs)., Methods: A point diffraction interferometer has been adapted to measure local prescriptions of PALs., Results: The most basic configuration of the interferometer for the measurement of PALs showed in this work presents high dynamic range and accuracy as well as the possibility of choosing the number and position of measurement points. Measurements are taken within a region of interest within a radius of about 0.4 to 1.5 mm. Different PAL designs are measured by the method proposed here and compared with results by a last generation commercial lens mapper. With the point diffraction interferometer we also compared several PAL designs in order to analyze their properties in the progression zone., Conclusions: The device is compact, robust, and fairly accurate, and the operational principle is very simple. By direct measurements it provides the local dioptric power, i.e., the second order wavefront properties, of the lens for selected regions of interest. The position and area can be chosen by the user. The only mobile part of the setup allows for the selection of the measurement points without any additional prismatic correction or movement of the PAL.