Search results for "Lens"
showing 10 items of 948 documents
Enhanced field-of-view integral imaging display using multi-Köhler illumination.
2014
A common drawback in 3D integral imaging displays is the appearance of pseudoimages beyond the viewing angle. These pseudoimages appear when the light rays coming from each elemental image are not passing through the corresponding microlens, and a set of barriers must be used to avoid this flipping effect. We present a pure optical arrangement based on Köhler illumination to generate these barriers thus avoiding the pseudoimages. The proposed system does not use additional lenses to project the elemental images, so no optical aberrations are introduced. As an added benefit, Köhler illumination provides a higher contrast 3D display. This work was supported in part by the Plan Nacional I + D …
The contribution of tear osmolarity measurement to ocular surface assessment in contact lens wearers
2012
Purpose: To determine whether tear osmolarity using the TearLabTM Osmolarity System contributes to the assessment of the ocular surface in contact lens (CL) wearers.Methods: Data were collected from 44 CL wearers (28 tolerant and 16 intolerant) and 34 healthy subjects. Every patient underwent a thorough ophthalmic examination and tear osmolarity test, conjunctival impression cytology and meibomian lipid sampling. Symptoms, break-up time (BUT), tear osmolarity, conjunctival expression of HLA-DR and meibomian fatty acid composition were evaluated.Results: Tear osmolarity was significantly higher in the controls compared to tolerant and intolerant CL wearers (p=0.0007). Flow cytometry results …
Accretion in strong field gravity with eXTP
2019
In this paper we describe the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission for studies related to accretion flows in the strong field gravity regime around both stellar-mass and supermassive black-holes. eXTP has the unique capability of using advanced 'spectral-timing-polarimetry' techniques to analyze the rapid variations with three orthogonal diagnostics of the flow and its geometry, yielding unprecedented insight into the inner accreting regions, the effects of strong field gravity on the material within them and the powerful outflows which are driven by the accretion process.
Direct Measurement of Focusing Fields in Active Plasma Lenses
2018
Physical review accelerators and beams 21(12), 122801 (2018). doi:10.1103/PhysRevAccelBeams.21.122801
Characterization and Tuning of Ultra High Gradient Permanent Magnet Quadrupoles
2009
The application of quadrupole devices with high field gradients and small apertures requires precise control over higher order multipole field components. We present a new scheme for performance control and tuning, which allows the illumination of most of the quadrupole device aperture because of the reduction of higher order field components. Consequently, the size of the aperture can be minimized to match the beam size achieving field gradients of up to $500\text{ }\text{ }\mathrm{T}\text{ }{\mathrm{m}}^{\ensuremath{-}1}$ at good imaging quality. The characterization method based on a Hall probe measurement and a Fourier analysis was confirmed using the high quality electron beam at the M…
Accommodative response in various design soft contact lens wearers
2021
The progression of myopia in young adults due to inadequate accommodation is currently one of the global research challenges. Studies have demonstrated that multifocal contact lenses have a different effect on accommodative response. The aim of this study was to assess the accommodative lag using various design multifocal contact lenses at different working distances. The study was conducted on 10 emmetropic subjects aged 22â28 years. An open-field autorefractor PowerRef 3 was used to assess the response of eye accommodation to stimuli placed at a distance of 25 cm and 40 cm for subjects wearing monofocal and multifocal contact lenses. To determine the effectiveness of contact lens design f…
Impact of viewing distance on relative depth judgements for stimuli in physical space
2019
In natural viewing, numerous depth cues are available to the visual system, but their significance varies considerably depending on the viewing distance. How is it reflected in the outcome of depth judgements? We have designed a psychophysical experiment with a limited number of depth cues to examine distance-related changes in the correct response rate and time. Twenty young adults evaluated relative depth of stimuli in physical space. Each time four constant angular size achromatic stimuli were presented on a volumetric multi-planar display. One of these stimuli was demonstrated closer to the observer comparing to others. The experiment followed the four-interval forced-choice procedure. …
Topical anti-inflammatory activity of some Asian medicinal plants used in dermatological disorders.
2001
The topical anti-inflammatory activity of extracts from Cassia angustifolia, Rheum palmatum, Coptis chinensis, Phellodendron amurense and Scutellaria baicalensis, plants used in traditional East Asian medicine against different skin disorders, was studied. Though in different degree, all the extracts significantly inhibited the edema induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), in both single or multiple application, oxazolone, and arachidonic acid (AA). None of the extracts inhibited in vitro the activity of phospholipase A(2) (PLA(2)) from Naja naja.
Preoperative simulation of postoperative iris-fixated phakic intraocular lens position and simulation of aging using high-resolution Scheimpflug imag…
2006
To increase postoperative safety after implantation of iris-fixated phakic intraocular lenses (pIOLs), optimal preoperative evaluation and patient selection is mandatory. We present a new software tool in a high-resolution Scheimpflug imaging device that precisely simulates the postoperative position of an iris-fixated pIOL and also simulates the effect of aging on the pIOL's position.