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Strehl ratio

Hong-Ting Liu, Zhou Zhou, Wu-Qiang Luo, Wen-Jing He, Owhofasa Agbedia, Jiang-Xia Wang, Jian-Zhong Huang, Xin Gao, Min Kong, Min Li, Li Li
AIM: To compare the optical quality after implantation of implantable collamer lens (ICL) and wavefront-guided laser in situ keratomileusis (WG-LASIK). METHODS: The study included 40 eyes of 22 patients with myopia who accepted ICL implantation and 40 eyes of 20 patients with myopia who received WG-LASIK. Before surgery and three months after surgery, the objective scattering index (OSI), the values of modulation transfer function (MTF) cutoff frequency, Strehl ratio, and the Optical Quality Analysis System (OQAS) values (OVs) were accessed...
2018: International Journal of Ophthalmology
Moritz Jesinghaus, Johanna Strehl, Melanie Boxberg, Frido Brühl, Adrian Wenzel, Björn Konukiewitz, Anna M Schlitter, Katja Steiger, Arne Warth, Andreas Schnelzer, Marion Kiechle, Matthias W Beckmann, Aurelia Noske, Arndt Hartmann, Grit Mehlhorn, Martin C Koch, Wilko Weichert
A novel histopathological grading system based on tumour budding and cell nest size has recently been shown to outperform conventional (WHO-based) grading algorithms in several tumour entities such as lung, oral, and oesophageal squamous cell carcinoma (SCC) in terms of prognostic patient stratification. Here, we tested the prognostic value of this innovative grading approach in two completely independent cohorts of SCC of the uterine cervix. To improve morphology-based grading, we investigated tumour budding activity and cell nest size as well as several other histomorphological factors (e...
April 2018: Journal of Pathology. Clinical Research
Pengfei Zhang, Jacopo Mocci, Daniel J Wahl, Ratheesh Kumar Meleppat, Suman K Manna, Martino Quintavalla, Riccardo Muradore, Marinko V Sarunic, Stefano Bonora, Edward N Pugh, Robert J Zawadzki
For in vivo mouse retinal imaging, especially with Adaptive Optics instruments, application of a contact lens is desirable, as it allows maintenance of cornea hydration and helps to prevent cataract formation during lengthy imaging sessions. However, since the refractive elements of the eye (cornea and lens) serve as the objective for most in vivo retinal imaging systems, the use of a contact lens, even with 0 Dpt. refractive power, can alter the system's optical properties. In this investigation we examined the effective focal length change and the aberrations that arise from use of a contact lens...
March 28, 2018: Experimental Eye Research
Richard A Frazin
The sensitivity of the pyramid wavefront sensor (PyWFS) has made it a popular choice for astronomical adaptive optics (AAO) systems. The PyWFS is at its most sensitive when it is used without modulation of the input beam. In nonmodulated mode, the device is highly nonlinear. Hence, all PyWFS implementations on current AAO systems employ modulation to make the device more linear. The upcoming era of 30-m class telescopes and the demand for ultra-precise wavefront control stemming from science objectives that include direct imaging of exoplanets make using the PyWFS without modulation desirable...
April 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Dong Hui Lim, Eui-Sang Chung, Myoung Joon Kim, Tae-Young Chung
AIM: To assess visual quality after presbyopia correction using an aspheric ablation profile and a micro-monovision protocol. METHODS: This is a retrospective interventional study. Fifty-four eyes of 27 patients (mean age, 50.2±7.5y) who underwent presbyopia correction with an aspheric micro-monovision protocol were enrolled. The values of modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI) and accommodation range were quantitatively assessed using the HD analyzer...
2018: International Journal of Ophthalmology
Dan Fu, Lin Wang, Xing-Tao Zhou, Zhi-Qiang Yu
AIM: To investigate cap morphology after small-incision lenticule extraction (SMILE) and its effects on intraocular scattering. METHODS: Sixty-five eyes of 33 patients undergoing SMILE were enrolled. In addition to regular evaluation, Fourier-domain optical coherence tomography was used to investigate cap thickness at 1d, 1wk, 1 and 3mo postoperatively. The optical quality including modulation transfer function cutoff frequency, Strehl ratio, Optical Quality Analysis System (OQAS) values, and objective scattering index (OSI), were evaluated using OQAS™...
2018: International Journal of Ophthalmology
Y Hua, G Chang, F X Kärtner, D N Schimpf
We demonstrate a pre-chirp managed amplification (PCMA) system that is based on two stages of core-pumped, polarization maintaining (PM) fiber amplifiers. It produces output pulses with <65 fs duration and >10 nJ pulse energy from single-mode fibers. Tailoring of the spectra in the amplification chain enables pulse compression to near-perfect transform limited pulses (Strehl-ratio >0.9) and low intensity noise levels (0.008%) despite B-integrals >40 rad in the PCMA amplifier. Design strategies are presented...
March 5, 2018: Optics Express
Xianwei Huang, Zhixiang Deng, Xiaohui Shi, Yanfeng Bai, Xiquan Fu
Based on the extended Huygens-Fresnel principle, we have derived the analytical expression of the average intensity of optical coherence lattices (OCLs) in oceanic turbulence with anisotropy, and then the beam quality parameters including the Strehl ratio (SR) and the power-in-the-bucket (PIB) are obtained. One can find that the OCLs will eventually evolve into Gaussian shape with the periodicity reciprocity gradually breaking down when propagating through the anisotropic ocean water, and that the trend of evolving into Gaussian can be accelerated for increasing the ratio of temperature and salinity contributions to the refractive index spectrum ω, the lattice constant a and the rate of dissipation of mean square temperature χT or decreasing the anisotropic factor ξ and the rate of dissipation of turbulent kinetic energy per unit mass of fluid ε...
February 19, 2018: Optics Express
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
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
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
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
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)
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
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
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
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
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
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
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
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