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Strehl ratio

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https://www.readbyqxmd.com/read/29420325/variation-of-coma-aberration-with-prismatic-soft-contact-lenses
#1
Carlos Carpena-Torres, José Manuel López-Alonso, Mercedes Burgos-Martínez, Gonzalo Carracedo, Jesús Carballo-Álvarez
PURPOSE: To analyze the variation in vertical coma and the rest of ocular aberrations before and after fitting prismatic soft contact lenses (PSCL). METHODS: Thirty-seven eyes of 20 healthy subjects (24.30±2.03 years) were evaluated to analyze the variation in ocular wavefront aberrations before and after fitting PSCL of different base-down prism values (1.0, 1.5, and 2.0 prism diopters [PD]), designed to study its influence in the compensation of vertical coma aberration...
February 7, 2018: Eye & Contact Lens
https://www.readbyqxmd.com/read/29401926/coherent-beam-combination-of-multiple-beams-based-on-near-field-angle-modulation
#2
Renqi Liu, Chun Peng, Weishu Wu, Xiaoyan Liang, Ruxin Li
We proposed a new phase-locking technique for multibeam coherent beam combination. By near-field angle modulation and angular spectrum measurement, we obtained the relative phase between each pair of beams with one camera. This method is appropriate for multibeam schemes and possesses the advantages of high accuracy, resistance to energy fluctuation, and simplicity, as shown by the analysis in this study. In a proof-of-principle experiment, we realized the phase-locking of three beams, achieving a Strehl ratio of 89...
January 22, 2018: Optics Express
https://www.readbyqxmd.com/read/29400796/digital-holographic-detection-in-the-off-axis-pupil-plane-recording-geometry-for-deep-turbulence-wavefront-sensing
#3
Matthias T Banet, Mark F Spencer, Robert A Raynor
This paper uses wave-optics and signal-to-noise models to explore the estimation accuracy of digital-holographic detection in the off-axis pupil plane recording geometry for deep-turbulence wavefront sensing. In turn, the analysis examines three important parameters: the number of pixels across the width of the focal-plane array, the window radius in the Fourier plane, and the signal-to-noise ratio. By varying these parameters, the wave-optics and signal-to-noise models quantify performance via a metric referred to as the field-estimated Strehl ratio, and the analysis leads to a method for optimal windowing of the turbulence-limited point spread function...
January 20, 2018: Applied Optics
https://www.readbyqxmd.com/read/29400718/evaluation-of-the-communication-quality-of-free-space-laser-communication-based-on-the-power-in-the-bucket-method
#4
Xianghui Yin, Rui Wang, Shaoxin Wang, Yukun Wang, Chengbin Jin, Zhaoliang Cao, Li Xuan
Atmospheric turbulence seriously affects the quality of free-space laser communication. The Strehl ratio (SR) is used to evaluate the effect of atmospheric turbulence on the receiving energy of free-space laser communication systems. However, the SR method does not consider the area of the laser-receiving end face. In this study, the power-in-the-bucket (PIB) method is demonstrated to accurately evaluate the effect of turbulence on the receiving energy. A theoretical equation is first obtained to calculate PIB...
February 1, 2018: Applied Optics
https://www.readbyqxmd.com/read/29383756/predicted-accommodative-response-from-image-quality-in-young-eyes-fitted-with-different-dual-focus-designs
#5
Miguel Faria-Ribeiro, Ana Amorim-de-Sousa, José M González-Méijome
PURPOSE: To investigate the separated and combined influences of inner zone (IZ) diameter and effective add power of dual-focus contact lenses (CL) in the image quality at distance and near viewing, in a functional accommodating model eye. METHODS: Computational wave-optics methods were used to define zonal bifocal pupil functions, representing the optic zones of nine dual-focus centre-distance CLs. The dual-focus pupil functions were defined having IZ diameters of 2...
January 31, 2018: Ophthalmic & Physiological Optics: the Journal of the British College of Ophthalmic Opticians (Optometrists)
https://www.readbyqxmd.com/read/29380760/interface-healing-and-its-correlation-with-visual-recovery-and-quality-of-vision-following-small-incision-lenticule-extraction
#6
Sri Ganesh, Sheetal Brar, Rahul Pandey, Archana Pawar
PURPOSE: To study the time course of interface healing and its correlation with visual acuity, modulation transfer function (MTF), and aberrations after myopic small-incision lenticule extraction (SMILE) correction. METHODS: Seventy-eight eyes of 78 patients (1 eye per patient) with a mean age of 25.7 years and mean spherical equivalent (SE) of -3.74D, undergoing bilateral SMILE procedure, were included in this study. On postoperative day 1, 2 weeks, and 3 months, dilated retroillumination photographs were taken and morphology of corneal interface was graded by comparing them with 5 standard templates representing 5 grades of interface roughness (IRG): IRG - 0 (clear), IRG - 1 (mild), IRG - 2 (moderate), IRG - 3 (severe), and IRG - 4 (severe IRG with Bowman's folds in visual axis)...
February 2018: Indian Journal of Ophthalmology
https://www.readbyqxmd.com/read/29377842/effects-of-lipid-versus-sodium-hyaluronate-containing-eye-drops-on-optical-quality-and-ocular-surface-parameters-as-a-function-of-the-meibomian-gland-dropout-rate
#7
Kata Miháltz, Eva Maria Faschinger, Pia Veronika Vécsei-Marlovits
PURPOSE: To evaluate the effect of lipid- versus sodium hyaluronate-based eye drops on optical quality and ocular surface parameters. METHODS: Sixty eyes of 30 patients with mild-to-moderate dry eye disease were included in a prospective randomized study. Each patient received either lipid- or sodium hyaluronate-based eye drops. Ocular symptom scores, breakup time, Schirmer test, fluorescein staining, noncontact meibography, and aberrometry were evaluated before and after 3 months of therapy...
January 25, 2018: Cornea
https://www.readbyqxmd.com/read/29297211/pupil-size-stability-of-the-cubic-phase-mask-solution-for-presbyopia
#8
Citlalli Almaguer, Eva Acosta, Justo Arines
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...
January 2018: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29240126/analysis-of-long-term-visual-quality-with-numerical-3d-ray-tracing-after-corneal-crosslinking-treatment
#9
Staffan Schedin, Per Hallberg, Anders Behndig
A numerical 3D ray tracing model was used to evaluate the long-term visual effects of two regimens of corneal crosslinking (CXL) treatment of 48 patients with the corneal degeneration keratoconus. The 3D ray tracing analyses were based on corneal elevation data measured by Scheimpflug photography. Twenty-two patients were treated with standard CXL applied uniformly across the corneal surface, whereas 26 patients underwent a customized, refined treatment only at local zones on the cornea (photorefractive intrastromal CXL; PiXL)...
December 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/29214074/tilt-decentration-and-internal-higher-order-aberrations-of-sutured-posterior-chamber-intraocular-lenses-in-patients-with-open-globe-injuries
#10
Xiangjia Zhu, Yinglei Zhang, Wenwen He, Hongfei Ye, Chunhui Jiang, Yi Lu
Purpose: To evaluate the tilt, decentration, and internal higher-order aberrations (HOAs) of sutured posterior-chamber intraocular lenses (IOLs) in patients with open globe injuries. Methods: 46 consecutive patients (47 eyes) who underwent transsclerally sutured IOL implantation were enrolled in this prospective cohort study. Nineteen eyes had a history of open globe injury. The tilt and decentration of the IOLs and the visual quality were measured 1 month after surgery...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/29146479/visual-outcome-of-penetrating-keratoplasty-deep-anterior-lamellar-keratoplasty-and-descemet-membrane-endothelial-keratoplasty
#11
Clàudia Garrido, Genís Cardona, Josep L Güell, Jaume Pujol
PURPOSE: A single-center, cross-sectional study was designed to assess and compare objective and subjective quality of vision of patients intervened with penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK). METHODS: Forty-six patients previously intervened with PK (22 eyes), DALK (7 eyes) and DMEK (17 eyes) were recruited. Visual evaluation included spherical and cylindrical refraction, distance corrected visual acuity (DCVA), photopic contrast sensitivity (CS), optical quality, measured with the HD Analyzer (objective scattering index [OSI], MTF cut-off and Strehl ratio), and ocular and corneal aberrometry, measured with the KR-1W Wavefront Analyzer...
November 13, 2017: Journal of Optometry
https://www.readbyqxmd.com/read/29120714/functional-magnetic-resonance-imaging-to-assess-neuroadaptation-to-multifocal-intraocular-lenses
#12
Andreia M Rosa, Ângela C Miranda, Miguel M Patrício, Colm McAlinden, Fátima L Silva, Miguel Castelo-Branco, Joaquim N Murta
PURPOSE: To evaluate the use of functional magnetic resonance imaging (MRI) to assess neuroadaptation to multifocal intraocular lenses (IOLs). SETTING: Faculty of Medicine, University of Coimbra, Coimbra, Portugal. DESIGN: Prospective case study. METHODS: Patients with bilateral diffractive IOL implantation after cataract surgery had functional MRI at postoperative intervals of 3 weeks and 6 months. A nonintervention control group was included as proof of concept...
October 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/29117609/-in-vitro-evaluation-of-the-optical-quality-of-segmental-refractive-multifocal-intraocular-lenses
#13
Timur Mert Yildirim, Gerd Uwe Auffarth, Tamer Tandogan, Stephanie Liebing, Grzegorz Labuz, Chul Young Choi, Ramin Khoramnia
Objectives In customised patient care, it is important to know the optical quality of different intraocular lenses (IOL). In this study, the optical quality of three segmental intraocular lenses were compared. Materials and Methods The LENTIS Comfort LS-313 MF15, LENTIS Mplus X LS-313 MF30 and LENTIS High Add IOL LS-313 MF80 (Oculentis, Berlin, Germany) with a far power of + 21 D were analysed at the optical bench OptiSpheric IOL PRO (Trioptics GmbH, Wedel, Germany). The lenses have almost the same optical design but differ in the power of the near segment...
November 8, 2017: Klinische Monatsblätter Für Augenheilkunde
https://www.readbyqxmd.com/read/29098084/influence-of-overnight-orthokeratology-on-corneal-surface-shape-and-optical-quality
#14
Yuan Sun, Lin Wang, Jing Gao, Mei Yang, Qi Zhao
Purpose: To investigate the changes of corneal surface shape and optical quality during orthokeratology. Methods: 49 eyes of 26 patients (10.63 ± 2.02 years old) who underwent overnight orthokeratology for myopia were prospectively examined. The corneal surface shape parameters, including surface regularity index (SRI) and surface asymmetry index (SAI), were attained with an OPD-III SCAN. The higher-order aberrations and higher-order Strehl ratios were calculated under a 3 mm pupil diameter before orthokeratology, 1 month, 3 months, and 6 months after orthokeratology...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/29047838/convolution-and-fourier-transform-based-reconstructors-for-pyramid-wavefront-sensor
#15
Iuliia Shatokhina, Ronny Ramlau
In this paper, we present two novel algorithms for wavefront reconstruction from pyramid-type wavefront sensor data. An overview of the current state-of-the-art in the application of pyramid-type wavefront sensors shows that the novel algorithms can be applied in various scientific fields such as astronomy, ophthalmology, and microscopy. Assuming a computationally very challenging setting corresponding to the extreme adaptive optics (XAO) on the European Extremely Large Telescope, we present the results of the performed end-to-end simulations and compare the achieved AO correction quality (in terms of the long-exposure Strehl ratio) to other methods, such as matrix-vector multiplication and preprocessed cumulative reconstructor with domain decomposition...
August 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/29041729/approaching-the-diffraction-limited-bandwidth-limited-petawatt
#16
Alexander S Pirozhkov, Yuji Fukuda, Mamiko Nishiuchi, Hiromitsu Kiriyama, Akito Sagisaka, Koichi Ogura, Michiaki Mori, Maki Kishimoto, Hironao Sakaki, Nicholas P Dover, Kotaro Kondo, Nobuhiko Nakanii, Kai Huang, Masato Kanasaki, Kiminori Kondo, Masaki Kando
J-KAREN-P is a high-power laser facility aiming at the highest beam quality and irradiance for performing state-of-the art experiments at the frontier of modern science. Here we approached the physical limits of the beam quality: diffraction limit of the focal spot and bandwidth limit of the pulse shape, removing the chromatic aberration, angular chirp, wavefront and spectral phase distortions. We performed accurate measurements of the spot and peak fluence after an f/1.3 off-axis parabolic mirror under the full amplification at the power of 0...
August 21, 2017: Optics Express
https://www.readbyqxmd.com/read/29027083/objective-and-subjective-results-following-implantation-of-the-finevision-trifocal-intraocular-lens-in-mexican-patients
#17
Ivo Ferreira-Ríos, Karla Zuñiga-Posselt, Juan Carlos Serna-Ojeda, Eduardo Chávez-Mondragón
PURPOSE: To evaluate objective and subjective results after bilateral implantation of a diffractive trifocal intraocular lens (IOL) in a Mexican population. METHODS: Prospective, interventional case series involved 15 cataract surgery patients who underwent bilateral implantation of the trifocal Micro F lens FineVision IOL (PhysIOL, Liège, Belgium). Objective analysis involved assessment of monocular uncorrected distance (UDVA), near (UNVA) at 30 and 40 cm, and intermediate visual acuity (UIVA) at 50, 60, and 70 cm, preoperatively, and at postoperative months 1, 3, and 6...
October 12, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/29026731/not-all-children-with-cystic-fibrosis-have-abnormal-esophageal-neutralization-during-chemical-clearance-of-acid-reflux
#18
Frederick W Woodley, Melissa Moore-Clingenpeel, Rodrigo Strehl Machado, Christopher J Nemastil, Sudarshan R Jadcherla, Don Hayes, Benjamin T Kopp, Ajay Kaul, Carlo Di Lorenzo, Hayat Mousa
PURPOSE: Acid neutralization during chemical clearance is significantly prolonged in children with cystic fibrosis, compared to symptomatic children without cystic fibrosis. The absence of available reference values impeded identification of abnormal findings within individual patients with and without cystic fibrosis. The present study aimed to test the hypothesis that significantly more children with cystic fibrosis have acid neutralization durations during chemical clearance that fall outside the physiological range...
September 2017: Pediatric Gastroenterology, Hepatology & Nutrition
https://www.readbyqxmd.com/read/29025173/-impact-of-near-addition-on-the-optical-quality-of-diffractive-multifocal-intraocular-lenses-a-laboratory-study-using-an-optical-bench
#19
Tamer Tandogan, Gerd Uwe Auffarth, Stephanie Liebing, Chul Young Choi, Ramin Khoramnia
Purpose To analyse the optical quality of diffractive multifocal intraocular lenses (IOLs) with different near additions in a laboratory study. Methods We analysed the AcrySof(®) IQ ReSTOR(®) + 2.5 D SV25T0 (Alcon Laboratories inc., Fort Worth, USA), the AcrySof(®) IQ ReSTOR(®) + 3.0 D SN6AD1 (Alcon, USA) and the TECNIS(®) ZMA00 and ZMB00 (Abbott Medical Optics, USA) with a power of 21D for the distance, using the OptiSpheric(®) IOL PRO optical bench (TRIOPTICS, Wedel, Germany). The lenses have a similar optical design but different near additions: The ReSTOR + 2...
October 12, 2017: Klinische Monatsblätter Für Augenheilkunde
https://www.readbyqxmd.com/read/28993199/unraveling-the-role-of-hypoxia-inducible-factor-hif-1%C3%AE-and-hif-2%C3%AE-in-the-adaption-process-of-human-microvascular-endothelial-cells-hmec-1-to-hypoxia-redundant-hif-dependent-regulation-of-macrophage-migration-inhibitory-factor
#20
Martin Hahne, Peggy Schumann, Mathias Mursell, Cindy Strehl, Paula Hoff, Frank Buttgereit, Timo Gaber
Hypoxia driven angiogenesis is a prominent feature of tissue regeneration, inflammation and tumor growth and is regulated by hypoxia-inducible factor (HIF)-1 and -2. The distinct functions of HIFs in the hypoxia-induced angiogenesis and metabolic switch of endothelial cells are still unknown and therefore aim of this study. We investigated the role of HIF-1 and -2 in the adaptation of immortalized human microvascular endothelial cells (HMEC-1) to hypoxic conditions (1% O2) in terms of angiogenesis, cytokine secretion, gene expression and ATP/ADP-ratio using shRNA-mediated reduction of the oxygen sensitive α-subunits of either HIF-1 or HIF-2 or the combination of both...
October 6, 2017: Microvascular Research
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