keyword
MENU ▼
Read by QxMD icon Read
search

WaveFront

keyword
https://www.readbyqxmd.com/read/28524133/-wavefront-aberrations-and-accommodation-in-myopes-and-hyperopes
#1
V V Neroev, E P Tarutta, S G Arutyunyan, A T Khandzhyan, N V Khodzhabekyan
AIM: to comparatively investigate accommodation, pseudoaccommodation, and higher-order aberrations in children and young adults with myopia and hyperopia. MATERIAL AND METHODS: A total of 39 myopic (the mean error of (-)5.2±1.5 diopters) and 53 hyperopic (the mean error of (+)3.1±1.15 diopters) eyes of 46 patients aged 5-20 years (11.6±0.6 years on average) were enrolled. Examination included evaluation of the objective accommodative response, relative accommodation reserves, pseudoaccommodation volume (calculated as the difference between the (+)3...
2017: Vestnik Oftalmologii
https://www.readbyqxmd.com/read/28522252/optical-quality-of-rotationally-symmetrical-contact-lenses-derived-from-their-power-profiles
#2
Antonio J Del Águila-Carrasco, Daniel Monsálvez-Romín, Eleni Papadatou
PURPOSE: To present a methodology for evaluating the optical quality of rotationally symmetrical contact lenses (CLs) from a single power profile. METHODS: Simulated rotationally symmetrical power profiles corresponding to different CLs designs (monofocal, two-zone center-near bifocal, and four-zone center-distance bifocal) were used to calculate the wavefront error profile by means of numerical integration. Then, each lens wavefront error profile was spun around the center to obtain the lens wavefront error surface...
May 15, 2017: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
https://www.readbyqxmd.com/read/28513498/combination-of-phototherapeutic-keratectomy-and-wavefront-guided-photorefractive-keratectomy-for-the-treatment-of-thiel-behnke-corneal-dystrophy
#3
Chia-Chieh Hsiao, Yu-Chih Hou
Phototherapeutic keratectomy (PTK) has been used to treat anterior corneal dystrophy but may cause hyperopic shift or corneal high-order aberration. We describe the successful treatment of a case of a 43-year-old female with Thiel-Behnke corneal dystrophy, using PTK followed by wavefront-guided photorefractive keratectomy (PRK). The patient had high corneal aberration and hyperopic shift after PTK in both eyes. The corneal surface regularity index and surface asymmetric index increased after PTK and decreased after wavefront-guided PRK...
April 2017: Indian Journal of Ophthalmology
https://www.readbyqxmd.com/read/28512572/experimental-strategies-for-imaging-bioparticles-with-femtosecond-hard-x-ray-pulses
#4
Benedikt J Daurer, Kenta Okamoto, Johan Bielecki, Filipe R N C Maia, Kerstin Mühlig, M Marvin Seibert, Max F Hantke, Carl Nettelblad, W Henry Benner, Martin Svenda, Nicuşor Tîmneanu, Tomas Ekeberg, N Duane Loh, Alberto Pietrini, Alessandro Zani, Asawari D Rath, Daniel Westphal, Richard A Kirian, Salah Awel, Max O Wiedorn, Gijs van der Schot, Gunilla H Carlsson, Dirk Hasse, Jonas A Sellberg, Anton Barty, Jakob Andreasson, Sébastien Boutet, Garth Williams, Jason Koglin, Inger Andersson, Janos Hajdu, Daniel S D Larsson
This study explores the capabilities of the Coherent X-ray Imaging Instrument at the Linac Coherent Light Source to image small biological samples. The weak signal from small samples puts a significant demand on the experiment. Aerosolized Omono River virus particles of ∼40 nm in diameter were injected into the submicrometre X-ray focus at a reduced pressure. Diffraction patterns were recorded on two area detectors. The statistical nature of the measurements from many individual particles provided information about the intensity profile of the X-ray beam, phase variations in the wavefront and the size distribution of the injected particles...
May 1, 2017: IUCrJ
https://www.readbyqxmd.com/read/28512297/flexible-two-photon-interference-fringes-with-thermal-light
#5
De-Zhong Cao, Cheng Ren, Jin-Yang Ni, Yan Zhang, Su-Heng Zhang, Kaige Wang
Flexible interference patterning is an important tool for adaptable measurement precisions. We report on experimental results of controllable two-photon interference fringes with thermal light in an incoherent rotational shearing interferometer. The two incoherent beams in the interferometer are orthogonally polarized, and their wavefront distributions differ only in an angle of rotation. The spacings and directions of the two-photon interference fringes vary with the rotation angle, as illustrated in three cases of two-photon correlation measurements in experiment...
May 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28507508/improving-focal-photostimulation-of-cortical-neurons-with-pre-derived-wavefront-correction
#6
Julian M C Choy, Sharmila S Sané, Woei M Lee, Christian Stricker, Hans A Bachor, Vincent R Daria
Recent progress in neuroscience to image and investigate brain function has been made possible by impressive developments in optogenetic and opto-molecular tools. Such research requires advances in optical techniques for the delivery of light through brain tissue with high spatial resolution. The tissue causes distortions to the wavefront of the incoming light which broadens the focus and consequently reduces the intensity and degrades the resolution. Such effects are detrimental in techniques requiring focal stimulation...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28506615/modelling-asymmetric-somitogenesis-deciphering-the-mechanisms-behind-species-differences
#7
Renske M A Vroomans, Kirsten H W J Ten Tusscher
Somitogenesis is one of the major hallmarks of bilateral symmetry in vertebrates. This symmetry is lost when retinoic acid (RA) signalling is inhibited, allowing the left-right determination pathway to influence somitogenesis. In all three studied vertebrate model species, zebrafish, chicken and mouse, the frequency of somite formation becomes asymmetric, with slower gene expression oscillations driving somitogenesis on the right side. Still, intriguingly, the resulting left-right asymmetric phenotypes differ significantly between these model species...
May 12, 2017: Developmental Biology
https://www.readbyqxmd.com/read/28504753/second-harmonic-focusing-by-a-nonlinear-turbid-medium-via-feedback-based-wavefront-shaping
#8
Yanqi Qiao, Yajun Peng, Yuanlin Zheng, Fangwei Ye, Xianfeng Chen
Scattering has usually been considered detrimental for optical focusing or imaging. Recently, more and more research has shown that strongly scattering materials can be utilized to focus coherent light by controlling or shaping the incident light. Here, purposeful focusing of second-harmonic waves, which are generated and scattered from nonlinear turbid media via feedback-based wavefront shaping, is presented. This Letter shows a flexible manipulation of both disordered linear and nonlinear scattering signals, indicating more controllable degrees of freedom for the description of turbid media...
May 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28504741/real-time-acquisition-of-complex-optical-fields-by-binary-amplitude-modulation
#9
Eduardo Peters, Pere Clemente, E Salvador-Balaguer, Enrique Tajahuerce, Pedro Andrés, Darío G Pérez, Jesús Lancis
We describe, through simulations and experiments, a real-time wavefront acquisition technique using random binary amplitude masks and an iterative phase retrieval algorithm based on the Fresnel propagator. By using a digital micromirror device, it is possible to recover an unknown complex object by illuminating with this set of masks and simultaneously recording the resulting intensity patterns with a high-speed camera, making this technique suitable for dynamic applications.
May 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28501948/corneal-tomography-and-biomechanics-in-primary-pterygium
#10
M Vanathi, Sahil Goel, Anita Ganger, Tushar Agarwal, T Dada, Sudarshan Khokhar
PURPOSE: To study the Scheimpflug's imaging and corneal biomechanics in primary pterygium. METHODS: A prospective observational study of 55 patients with unilateral primary nasal pterygium was done. The normal fellow eyes of patients with pterygium were taken as controls. Clinical parameters noted included visual acuity, values of corneal curvature by doing Scheimpflug imaging, wavefront aberrations in terms of higher and lower-order aberrations and corneal hysteresis (CH) as well as corneal resistance factor (CRF) values by using ocular response analyzer...
May 13, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28500175/spatial-resolution-requirements-for-accurate-identification-of-drivers-of-atrial-fibrillation
#11
Caroline H Roney, Chris D Cantwell, Jason D Bayer, Norman A Qureshi, Phang Boon Lim, Jennifer H Tweedy, Prapa Kanagaratnam, Nicholas S Peters, Edward J Vigmond, Fu Siong Ng
BACKGROUND: Recent studies have demonstrated conflicting mechanisms underlying atrial fibrillation (AF), with the spatial resolution of data often cited as a potential reason for the disagreement. The purpose of this study was to investigate whether the variation in spatial resolution of mapping may lead to misinterpretation of the underlying mechanism in persistent AF. METHODS AND RESULTS: Simulations of rotors and focal sources were performed to estimate the minimum number of recording points required to correctly identify the underlying AF mechanism...
May 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28491466/changes-in-retinal-function-and-cellular-remodeling-following-experimental-retinal-detachment-in-a-rabbit-model
#12
Tilda Barliya, Ron Ofri, Shai Sandalon, Dov Weinberger, Tami Livnat
Purpose. To explore functional electroretinographic (ERG) changes and associated cellular remodeling following experimental retinal detachment in a rabbit model. Methods. Retinal detachment was created in ten rabbits by injecting 0.1 ml balanced salt solution under the retina. Fundus imaging was performed 0, 3, 7, 14, and 21 days postoperatively. ERGs were recorded pre- and 7 and 21 days postoperatively. Eyes were harvested on day 21 and evaluated immunohistochemically (IHC) for remodeling of second- and third-order neurons...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/28486724/noncontact-quantification-of-topography-of-anterior-corneal-surface-and-bowman-s-layer-with-high-speed-oct
#13
Himanshu Matalia, Mathew Francis, Tarun Gangil, Rachana S Chandapura, Mathew Kurian, Rohit Shetty, Everette Jacob Remington Nelson, Abhijit Sinha Roy
PURPOSE: To quantify keratometry and wavefront aberration of the anterior corneal surface and epithelium-Bowman's layer interface using anterior segment optical coherence tomography (OCT). METHODS: Twenty-five normal eyes and 25 eyes with keratoconus were retrospectively analyzed. The anterior corneal edge and epithelium-Bowman's layer interface were segmented from 12 distortion-corrected OCT B-scans. Axial tangential curvatures and wavefront aberration were calculated by ray tracing and 6th order Zernike analyses...
May 1, 2017: Journal of Refractive Surgery
https://www.readbyqxmd.com/read/28486720/comparative-analysis-of-the-clinical-outcomes-of-smile-and-wavefront-guided-lasik-in-low-and-moderate-myopia
#14
Mounir A Khalifa, Ahmed Ghoneim, Mohamed Shafik Shaheen, Mohamed G Aly, David P Piñero
PURPOSE: To compare the clinical outcomes of small incision lenticule extraction (SMILE) and wavefront-guided LASIK (WFG LASIK) in eyes with low and moderate myopia. METHODS: This was a prospective, comparative study enrolling 110 eyes with low and moderate myopia (spherical equivalent ≤ 6.00 diopters [D]). Two groups were differentiated according to the surgical technique used: the WFG LASIK group included 51 eyes (51 patients) undergoing WFG LASIK using the STAR S4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Abbott Park, IL) and the SMILE group included 59 eyes (59 patients) undergoing SMILE with the VisuMax platform (Carl Zeiss Meditec, Jena, Germany)...
May 1, 2017: Journal of Refractive Surgery
https://www.readbyqxmd.com/read/28481364/large-field-of-view-imaging-by-multi-pupil-adaptive-optics
#15
Jung-Hoon Park, Lingjie Kong, Yifeng Zhou, Meng Cui
Adaptive optics can correct for optical aberrations. We developed multi-pupil adaptive optics (MPAO), which enables simultaneous wavefront correction over a field of view of 450 × 450 μm(2) and expands the correction area to nine times that of conventional methods. MPAO's ability to perform spatially independent wavefront control further enables 3D nonplanar imaging. We applied MPAO to in vivo structural and functional imaging in the mouse brain.
May 8, 2017: Nature Methods
https://www.readbyqxmd.com/read/28479513/epicardial-endocardial-breakthrough-during-stable-atrial-macro-reentry-evidence-from-ultra-high-resolution-three-dimensional-mapping-epicardial-endocardial-breakthrough-in-atrial-macro-reentry
#16
Bhupesh Pathik, Geoffrey Lee, Frédéric Sacher, Michel Haïssaguerre, Pierre Jaïs, Grégoire Massoullié, Nicolas Derval, Prashanthan Sanders, Peter Kistler, Jonathan M Kalman
BACKGROUND: Evidence for epicardial-endocardial breakthrough(EEB) is derived from mapping inferences in patients with AF who may also have focal activations. OBJECTIVES: We investigated whether EEB could be discerned during stable right atrial macro-reentry using high-density high-spatial resolution 3D mapping. METHODS: Macro-reentry was diagnosed using 3D mapping and entrainment. Bipolar maps were reviewed for EEB defined as (i)focal endocardial activation with radial spread unaccounted for by an endocardial wavefront and (ii)present with the same timing on every tachycardia cycle...
May 4, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28476316/aberration-free-intraocular-lenses-what-does-this-really-mean
#17
Achim Langenbucher, Simon Schröder, Alan Cayless, Timo Eppig
BACKGROUND: So-called aberration-free intraocular lenses (IOLs) are well established in modern cataract surgery. Usually, they are designed to perfectly refract a collimated light beam onto the focal point. METHODS: We show how much aberration can be expected with such an IOL in a convergent light beam such as that found anterior to the human cornea. Additionally, the aberration in a collimated beam is estimated for an IOL that has no aberrations in the convergent beam...
May 3, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28470981/active-phase-transition-via-loss-engineering-in-a-terahertz-mems-metamaterial
#18
Longqing Cong, Prakash Pitchappa, Chengkuo Lee, Ranjan Singh
Controlling the phase of local radiation by using exotic metasurfaces has enabled promising applications in a diversified set of electromagnetic wave manipulation such as anomalous wavefront deflection, flat lenses, and holograms. Here, we theoretically and experimentally demonstrate an active phase transition in a micro-electromechanical system-based metadevice where both the phase response and the dispersion of the metamaterial cavity are dynamically tailored. The phase transition is determined by the radiative and the absorptive losses in a metal-insulator-metal cavity that obeys the coupled-mode theory...
May 4, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28468409/three-dimensional-focusing-through-scattering-media-using-conjugate-adaptive-optics-with-remote-focusing-caorf
#19
Xiaodong Tao, Tuwin Lam, Bingzhao Zhu, Qinggele Li, Marc R Reinig, Joel Kubby
The small correction volume for conventional wavefront shaping methods limits their application in biological imaging through scattering media. We demonstrate large volume wavefront shaping through a scattering layer with a single correction by conjugate adaptive optics and remote focusing (CAORF). The remote focusing module can maintain the conjugation between the adaptive optical (AO) element and the scattering layer during three-dimensional scanning. This new configuration provides a wider correction volume by better utilization of the memory effect in a fast three-dimensional laser scanning microscope...
May 1, 2017: Optics Express
https://www.readbyqxmd.com/read/28468364/process-oriented-adaptive-optics-control-method-in-the-multi-pass-amplifiers
#20
Qiao Xue, Deen Wang, Xiaolu Zhang, Fa Zeng, Song Gao, Ke Yao, Ying Yang, Xin Zhang, Qiang Yuan, Junpu Zhao, Xudong Xie, Wanjun Dai, Dongxia Hu, Kuixing Zheng, Qihua Zhu
In this talk, we propose and demonstrate the process-oriented adaptive optics (AO) wavefront control method, for optimizing the beam quality in the multi-pass amplifiers. Different from the conventional target-oriented wavefront control approach, the novel method divides the aberration correction process into several steps, to optimize the wavefront quality in time during the courses of the beam's transport and amplification. The experimental results show that the proposed method can effectively prevent the beam quality from worsening and ensure the successful reality of multi-pass amplification, so it has obvious advantages both in efficiency and accuracy over the traditional target-oriented method...
May 1, 2017: Optics Express
keyword
keyword
104439
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"