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https://www.readbyqxmd.com/read/28101398/wide-field-retinal-optical-coherence-tomography-with-wavefront-sensorless-adaptive-optics-for-enhanced-imaging-of-targeted-regions
#1
James Polans, Brenton Keller, Oscar M Carrasco-Zevallos, Francesco LaRocca, Elijah Cole, Heather E Whitson, Eleonora M Lad, Sina Farsiu, Joseph A Izatt
The peripheral retina of the human eye offers a unique opportunity for assessment and monitoring of ocular diseases. We have developed a novel wide-field (>70°) optical coherence tomography system (WF-OCT) equipped with wavefront sensorless adaptive optics (WSAO) for enhancing the visualization of smaller (<25°) targeted regions in the peripheral retina. We iterated the WSAO algorithm at the speed of individual OCT B-scans (~20 ms) by using raw spectral interferograms to calculate the optimization metric...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28096651/effects-of-3-diquafosol-sodium-ophthalmic-solution-on-higher-order-aberrations-in-patients-diagnosed-with-dry-eye-after-cataract-surgery
#2
Yasushi Inoue, Shintarou Ochi
PURPOSE: To evaluate the effects of diquafosol sodium ophthalmic solution 3% (DQS) and artificial tears (AT) on higher-order aberrations (HOAs) in patients with dry eye after cataract surgery. DESIGN: This was a post hoc analysis of a previously conducted randomized clinical study. METHODS: Fifty-nine eyes from 42 patients (17 males and 25 females, aged 72.6±8.0 years) with verified or suspected dry eye at 4 weeks after cataract surgery were evaluated...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/28087631/papc-couples-the-segmentation-clock-to-somite-morphogenesis-by-regulating-n-cadherin-dependent-adhesion
#3
Jérome Chal, Charlène Guillot, Olivier Pourquié
Vertebrate segmentation is characterized by the periodic formation of epithelial somites from the mesenchymal presomitic mesoderm (PSM). How the rhythmic signaling pulse delivered by the Segmentation Clock is translated into the periodic morphogenesis of somites remains poorly understood. Here, we focused on the role of Paraxial protocadherin (PAPC/Pcdh8) in this process. We showed that in chicken and mouse embryos, PAPC expression is tightly regulated by the Clock and Wavefront system in the posterior PSM...
January 13, 2017: Development
https://www.readbyqxmd.com/read/28070079/improvement-of-spatial-resolution-for-nonlinear-raman-microscopy-by-spatial-light-modulation
#4
Motohiro Banno, Konosuke Onda, Hiroharu Yui
The development of a stimulated Raman scattering (SRS) microscope with a wavefront modulation unit is presented. In the apparatus, two beams for introducing the SRS process were focused into the sample with an objective lens. In the pathway of the Stokes beam, which is one of the two incident beams, a spatial light modulator (SLM) was located. Using the SLM, the wavefront of the Stokes beam was modulated to make the shape of the focal point a concentric circular pattern. By this spot shaping technique, the area where the SRS signal generates is restricted...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
https://www.readbyqxmd.com/read/28068440/a-prospective-study-to-compare-visual-outcomes-between-wavefront-optimized-and-topography-guided-ablation-profiles-in-contralateral-eyes-with-myopia
#5
Rohit Shetty, Rushad Shroff, Kalyani Deshpande, Roshan Gowda, Sumeet Lahane, Chaitra Jayadev
PURPOSE: To analyze refractive outcomes of wavefront-optimized (WFO) ablation and topography-guided custom ablation (TCAT) profiles using the Allegretto Wave excimer laser platform (Alcon Laboratories, Inc., Fort Worth, TX) in the treatment of myopia. METHODS: Sixty eyes of 30 patients who underwent LASIK were included in this prospective interventional study. WFO ablation was performed in one eye (WFO group) and TCAT in the fellow eye (TCAT group). The WaveLight FS200 femtosecond laser (Alcon Laboratories, Inc...
January 1, 2017: Journal of Refractive Surgery
https://www.readbyqxmd.com/read/28063269/novel-mapping-technique-for-localization-of-focal-and-reentrant-activation-during-atrial-fibrillation
#6
Yoshihide Takahashi, Shinsuke Iwai, Syu Yamashita, Mayumi Masumura, Masahito Suzuki, Kento Yabe, Yasuhiro Sato, Kenzo Hirao, Mitsuaki Isobe
INTRODUCTION: Identification of wavefront propagation pattern during AF remains challenging in ablation procedures. We sought to test a novel combination of a new mapping technology called Ripple Map and high density mapping to distinguish focal and reentrant activation during atrial fibrillation (AF). METHODS AND RESULTS: Subjects were patients undergoing ablation for persistent AF. If AF remained after isolation of the pulmonary veins, the left atrium (LA) was mapped by a high-density mapping catheter for later analysis, after which ablation was continued using a conventional stepwise approach...
January 7, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28062928/evaluation-of-paraxial-forward-scattering-from-intraocular-lens-with-increased-surface-light-scattering-using-goniophotometry-and-hartmann-shack-wavefront-aberrometry
#7
Keiichiro Minami, Yoko Maruyama, Toshifumi Mihashi, Kazunori Miyata, Tetsuro Oshika
PURPOSE: To evaluate the influence of increases in light scattering on intraocular lens (IOL) surfaces on paraxial forward scattering using goniophotometry and Hartmann-Shack wavefront aberrometry. METHODS: Surface light scattering was reproduced experimentally by acceleratedly aging 4 intraocular lenses by 0, 3, 5, and 10 years each. Light scattering from both IOL surfaces was measured using Scheimpflug photography. The paraxial forward scattering from the aged IOLs was measured using a goniophotometer with a halogen light source (wavelength: 350-850 nm) and telecentric optics, and changes in the maximum intensity and full width at 10% of maximum intensity (FW10%) were evaluated...
January 6, 2017: Japanese Journal of Ophthalmology
https://www.readbyqxmd.com/read/28060075/removal-and-repositioning-of-intracorneal-ring-segments-improving-corneal-topography-and-clinical-outcomes-in-keratoconus-and-ectasia
#8
Kahei Chan, Peter S Hersh
PURPOSE: To evaluate the efficacy of removal and relocation of intracorneal ring segments for improving outcomes in treatment of keratoconus and corneal ectasia. METHODS: This is a retrospective case series conducted at a cornea and refractive surgery subspecialty practice setting. Patients with previous insertion of 2 intracorneal ring segments underwent surgical removal and repositioning of segments because of unsatisfactory visual and topographic outcomes. The principal outcomes included uncorrected and corrected visual acuities, manifest refraction, topography-derived maximum keratometry (Kmax), inferior-superior topography power difference (I - S), and higher-order aberration profile derived from wavefront analysis...
February 2017: Cornea
https://www.readbyqxmd.com/read/28059371/plenoptic-mapping-for-imaging-and-retrieval-of-the-complex-field-amplitude-of-a-laser-beam
#9
Chensheng Wu, Jonathan Ko, Christopher C Davis
The plenoptic sensor has been developed to sample complicated beam distortions produced by turbulence in the low atmosphere (deep turbulence or strong turbulence) with high density data samples. In contrast with the conventional Shack-Hartmann wavefront sensor, which utilizes all the pixels under each lenslet of a micro-lens array (MLA) to obtain one data sample indicating sub-aperture phase gradient and photon intensity, the plenoptic sensor uses each illuminated pixel (with significant pixel value) under each MLA lenslet as a data point for local phase gradient and intensity...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28059273/flexible-and-achromatic-generation-of-optical-vortices-by-use-of-vector-beam-recorded-functionalized-liquid-crystals
#10
Moritsugu Sakamoto, Tomoyuki Sasaki, Tran Mien Tien, Kohei Noda, Nobuhiro Kawatsuki, Hiroshi Ono
In this study, we investigated the spatial light modulation properties of an optical vortex (OV) generator consisting of azo-dye-doped polymer liquid crystal (ADDLC) and a vector beam illuminator, focusing on flexibility and achromaticity for generating OVs. Uniaxially aligned ADDLC forms three-dimensional photoinduced twisted anisotropic structures under vector beam illumination, and can generate high-order OVs with even-numbered topological charges that correspond to the polarization pattern of the illuminating vector beam...
December 20, 2016: Applied Optics
https://www.readbyqxmd.com/read/28059265/investigation-of-phase-object-trace-duplication-in-moir%C3%A3-deflectometry
#11
Mohammad Ahmadi, Khosro Madanipour
In a deflectometry experiment for finding the temperature distribution around a hot wire as a phase object, the trace of the wire in a moiré pattern is duplicated, and it is observed that the separation of the wire traces varies when the distance between two gratings of a moiré deflectometry setup is changed. By investigation of moiré deflectometry, it is found that the object trace duplication cannot be interpreted by ray deflection theory, which is based on geometric optics. By using diffraction theory, the effect of a phase object on a moiré pattern is studied, and some generalized formulations are presented...
December 20, 2016: Applied Optics
https://www.readbyqxmd.com/read/28059255/complex-amplitude-reconstruction-for-dynamic-beam-quality-m-sup-2-sup-factor-measurement-with-self-referencing-interferometer-wavefront-sensor
#12
Yongzhao Du, Yuqing Fu, Lixin Zheng
A real-time complex amplitude reconstruction method for determining the dynamic beam quality M<sup>2</sup> factor based on a Mach-Zehnder self-referencing interferometer wavefront sensor is developed. By using the proposed complex amplitude reconstruction method, full characterization of the laser beam, including amplitude (intensity profile) and phase information, can be reconstructed from a single interference pattern with the Fourier fringe pattern analysis method in a one-shot measurement. With the reconstructed complex amplitude, the beam fields at any position z along its propagation direction can be obtained by first utilizing the diffraction integral theory...
December 20, 2016: Applied Optics
https://www.readbyqxmd.com/read/28059209/enhanced-visualization-of-peripheral-retinal-vasculature-with-wavefront-sensorless-adaptive-optics-optical-coherence-tomography-angiography-in-diabetic-patients
#13
James Polans, David Cunefare, Eli Cole, Brenton Keller, Priyatham S Mettu, Scott W Cousins, Michael J Allingham, Joseph A Izatt, Sina Farsiu
Optical coherence tomography angiography (OCTA) is a promising technique for non-invasive visualization of vessel networks in the human eye. We debut a system capable of acquiring wide field-of-view (>70°) OCT angiograms without mosaicking. Additionally, we report on enhancing the visualization of peripheral microvasculature using wavefront sensorless adaptive optics (WSAO). We employed a fast WSAO algorithm that enabled wavefront correction in <2  s by iterating the mirror shape at the speed of OCT B-scans rather than volumes...
January 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28058160/long-term-results-of-small-incision-lenticule-extraction-in-high-myopia
#14
Yusuf Yıldırım, Cengiz Alagöz, Abdülvahit Demir, Onur Ölçücü, Mehmet Özveren, Alper Ağca, Engin Bilge Özgürhan, Ahmet Demirok
OBJECTIVES: To evaluate two-year results of small-incision lenticule extraction (SMILE) for correction of high myopia. MATERIALS AND METHODS: Forty-five eyes of 35 patients with mean spherical equivalent (SE) of -7.10±0.95 D who underwent routine SMILE by a single surgeon and were followed for at least 2 years were analyzed by retrospective chart review. SMILE was performed with a Visumax femtosecond laser (Carl Zeiss Meditec, Jena, Germany). Follow-up intervals were at 1, 6, 12, and 24 months after surgery...
October 2016: Turkish Journal of Ophthalmology
https://www.readbyqxmd.com/read/28051986/wavefront-guided-versus-wavefront-optimized-photorefractive-keratectomy-visual-and-military-task-performance
#15
Denise S Ryan, Rose K Sia, Richard D Stutzman, Joseph F Pasternak, Robin S Howard, Christopher L Howell, Tana Maurer, Mark F Torres, Kraig S Bower
PURPOSE: To compare visual performance, marksmanship performance, and threshold target identification following wavefront-guided (WFG) versus wavefront-optimized (WFO) photorefractive keratectomy (PRK). METHODS: In this prospective, randomized clinical trial, active duty U.S. military Soldiers, age 21 or over, electing to undergo PRK were randomized to undergo WFG (n = 27) or WFO (n = 27) PRK for myopia or myopic astigmatism. Binocular visual performance was assessed preoperatively and 1, 3, and 6 months postoperatively: Super Vision Test high contrast, Super Vision Test contrast sensitivity (CS), and 25% contrast acuity with night vision goggle filter...
January 2017: Military Medicine
https://www.readbyqxmd.com/read/28046718/mo-fg-campus-tep1-03-pre-treatment-surface-imaging-based-collision-detection
#16
D Wiant, J Maurer, H Liu, T Hayes, Q Shang, B Sintay
PURPOSE: Modern radiotherapy increasingly employs large immobilization devices, gantry attachments, and couch rotations for treatments. All of which raise the risk of collisions between the patient and the gantry / couch. Collision detection is often achieved by manually checking each couch position in the treatment room and sometimes results in extraneous imaging if collisions are detected after image based setup has begun. In the interest of improving efficiency and avoiding extra imaging, we explore the use of a surface imaging based collision detection model...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28045036/speed-hysteresis-and-noise-shaping-of-traveling-fronts-in-neural-fields-role-of-local-circuitry-and-nonlocal-connectivity
#17
Cristiano Capone, Maurizio Mattia
Neural field models are powerful tools to investigate the richness of spatiotemporal activity patterns like waves and bumps, emerging from the cerebral cortex. Understanding how spontaneous and evoked activity is related to the structure of underlying networks is of central interest to unfold how information is processed by these systems. Here we focus on the interplay between local properties like input-output gain function and recurrent synaptic self-excitation of cortical modules, and nonlocal intermodular synaptic couplings yielding to define a multiscale neural field...
January 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28040628/two-dimensional-analytic-modeling-of-acoustic-diffraction-for-ultrasonic-beam-steering-by-phased-array-transducers
#18
Tiansi Wang, Chong Zhang, Aleksandar Aleksov, Islam Salama, Aravinda Kar
Phased array ultrasonic transducers enable modulating the focal position of the acoustic waves, and this capability is utilized in many applications, such as medical imaging and non-destructive testing. This type of transducers also provides a mechanism to generate tilted wavefronts in acousto-optic deflectors to deflect laser beams for high precision advanced laser material processing. In this paper, a theoretical model is presented for the diffraction of ultrasonic waves emitted by several phased array transducers into an acousto-optic medium such as TeO2 crystal...
December 9, 2016: Ultrasonics
https://www.readbyqxmd.com/read/28035498/accelerated-versus-conventional-corneal-collagen-cross-linking-in-patients-with-keratoconus-an-intrapatient-comparative-study
#19
Mohammad Mehdi Sadoughi, Bahram Einollahi, Alireza Baradaran-Rafii, Danial Roshandel, Hamidreza Hasani, Mehrdad Nazeri
PURPOSE: To compare the outcomes of the conventional and accelerated corneal collagen cross-linking (CXL) in patients with bilateral progressive keratoconus (KC). METHODS: Fifteen consecutive patients with bilateral progressive KC were enrolled. In each patient, the fellow eyes were randomly assigned to the conventional CXL (3 mW/cm(2) for 30 min) or accelerated CXL (ACXL) (9 mW/cm(2) for 10 min) groups. Manifest refraction; uncorrected and corrected distant visual acuity; maximum and mean keratometry; corneal hysteresis and corneal resistance factor; endothelial cell density and morphology; central corneal thickness; and wavefront aberrations were measured before and 12 months after the CXL...
December 29, 2016: International Ophthalmology
https://www.readbyqxmd.com/read/28009554/x-ray-grating-interferometer-for-in%C3%A2-situ-and-at-wavelength-wavefront-metrology
#20
Yves Kayser, Christian David, Uwe Flechsig, Juraj Krempasky, Volker Schlott, Rafael Abela
A wavefront metrology setup based on the X-ray grating interferometry technique for spatially resolved, quantitative, in situ and at-wavelength measurements of the wavefront at synchrotron radiation and hard X-ray free-electron laser beamlines is reported. Indeed, the ever-increasing demands on the optical components to preserve the wavefront shape and the coherence of the delivered X-ray beam call for more and more sensitive diagnostic instruments. Thanks to its angular sensitivity, X-ray grating interferometry has been established in recent years as an adequate wavefront-sensing technique for quantitatively assessing the quality of the X-ray wavefront under working conditions and hence for the in situ investigation of X-ray optical elements...
January 1, 2017: Journal of Synchrotron Radiation
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