Search results for " Lens"
showing 10 items of 510 documents
OGLE-2008-BLG-510: first automated real-time detection of a weak microlensing anomaly - brown dwarf or stellar binary?
2012
The microlensing event OGLE-2008-BLG-510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system in real time. The skewness of the light curve appears to be compatible both with binary-lens and binary-source models, including the possibility that the lens system consists of an M dwarf orbited by a brown dwarf. The detection of this microlensing anomaly and our analysis demonstrate that: (1) automated real-time detection of weak microlensing anomalies with immediate feedback is feasible, efficient and sensitive, (2) rather common weak features intrinsically come with ambiguities that ar…
Visual and refractive outcomes in hyperopic pseudophakic patients implanted with a trifocal intraocular lens
2019
José F Alfonso,1,2 Andrés Fernández-Vega-Cueto,1 Belén Alfonso-Bartolozzi,1 Ignacio Rodríguez-Uña,1 Robert Montés-Micó3 1Corneal and Lens Surgery Department, Fernández-Vega Ophthalmological Institute, Oviedo, Spain; 2Surgery Department, School of Medicine, University of Oviedo, Oviedo, Spain; 3Optics and Optometry and Vision Sciences Department, Faculty of Physics, University of Valencia, Valencia, SpainCorrespondence: José F AlfonsoInstituto Oftalmológico Fernández-Vega, Avda. Dres. Fernández-Vega 114, Oviedo 33012, SpainTel +34 985 245533Fax +34 98…
Kontaktlēcu ietekme uz redzes asumu pacientiem ar neregulāru radzeni
2017
Darbs uzrakstīts angļu valodā uz 39 lapām. Tas satur 11 attēlus, 1 aptaujas lapu, 11 tabulas and 24 atsauces uz literatūras avotiem. Mērķis: darba galvenais mērķis ir salīdzināt parastās gāzu caurlaidīgās kontaktlēcas ar gāzu caurlaidīgajām intralimbālajām lēcām. Metodes: gāzu caurlaidīgās intralimbālās lēcas tika novērtētas, pētījuma dalībniekiem aizpildot anketu. Rezultāti: pētījuma dalībnieki deva priekšroku gāzu caurlaidīgajām intralimbālajām lēcām un novērtēja to sniegto komfortu, tomēr nebija būtiskas atšķirības starp iegūto redzes asumu abu lēcu gadījumā. Secinājumi: izvērtējot katra pacienta individuālo sutāciju, optometrists var apsvērt intralimbālo lēcu izrakstīšanu pecientam, lai…
Kontaktlēcu pacientu līdzestība un nelīdzestības iemesli Latvijā
2019
Bakalaura darbs ir uzrakstīts latviešu valodā uz 73 lapām. Darbs sastāv no ievada, teorētiskās un praktiskās daļas. Darbs satur 42 attēlus, 6 tabulas, 3 pielikumus un 63 literatūras avotu atsauces. Bakalaura darba mērķis: Novērtēt kontaktlēcu pacientu līdzestības un nelīdzestības iemeslus Latvijā. Bakalaura darba uzdevumi: 1. Ar anketēšanas palīdzību noskaidrot un salīdzināt kontaktlēcu lietotāju un optometristu asistentu zināšanas par kontaktlēcu lietošanu un kopšanu. 2. Noskaidrot kontaktlēcu lietotāju biežākās sūdzības. 3. Novērtēt kontaktlēcu lietotāju līdzestību. Metode: Izveidotas 3 anketas. Kontaktlēcu lietotāju anketa izveidotā divās valodas (latviešu un krievu valodā) un sastāv no …
Euclid preparation. XII. Optimizing the photometric sample of the Euclid survey for galaxy clustering and galaxy-galaxy lensing analyses
2021
Pocino, A., et al. (Euclid Collaboration)
Generation of programmable 3D optical vortex structures through devil’s vortex-lens arrays
2013
Different spatial distributions of optical vortices have been generated and characterized by implementing arrays of devil's vortex lenses in a reconfigurable spatial light modulator. A simple design procedure assigns the preferred position and topological charge value to each vortex in the structure, tuning the desired angular momentum. Distributions with charges and momenta of the opposite sign have been experimentally demonstrated. The angular velocity exhibited by the phase distribution around the focal plane has been visualized, showing an excellent agreement with the simulations. The practical limits of the method, with interest for applications involving particle transfer and manipula…
Behavioural thresholds of blue tit colour vision and the effect of background chromatic complexity
2020
Vision is a vital attribute to foraging, navigation, mate selection and social signalling in animals, which often have a very different colour perception in comparison to humans. For understanding how animal colour perception works, vision models provide the smallest colour difference that animals of a given species are assumed to detect. To determine the just-noticeable-difference, or JND, vision models use Weber fractions that set discrimination thresholds of a stimulus compared to its background. However, although vision models are widely used, they rely on assumptions of Weber fractions since the exact fractions are unknown for most species. Here, we test; i) which Weber fractions in lo…
Determining postoperative anterior chamber depth
2003
Abstract Purpose: To compare measured and calculated postoperative anterior chamber depths (ACDs). Setting: Department of Ophthalmology and Institute of Medical Physics, University of Vienna, Vienna, Austria, and Department of Ophthalmology, University of Mainz, Mainz, Germany. Methods: The postoperative ACD was measured in 189 pseudophakic eyes using a laboratory prototype of partial coherence interferometry (PCI). In 6 intraocular lens (IOL) groups, the mean ACD was calculated by ray tracing based on the best-known A-constants of the SRK formulas. In addition, for each IOL type, each measured ACD was compared with a value calculated using the individual spherical equivalent of the postope…
Comparison of biometric measurements using partial coherence interferometry and applanation ultrasound
2003
Abstract Purpose To compare and contrast axial length (AL) measurements assessed by ultrasound biometry and optical biometry. Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods Optical biometry and ultrasound biometry were performed in 360 eyes to measure AL. Results In eyes with a clear-appearing crystalline lens, there was a statistically significant median difference in AL measurements between the 2 methods in eyes with a normal or long length. In eyes with cataract, there was a statistically significant median difference in AL measurements in eyes with a normal or short length. In these cases, optical biometry produced larger readings than ultras…
Bacterial Contamination of Anterior Chamber Fluid Following Non-complicated Cataract Surgery
1993
Objective: To study the anterior chamber contamination during non-complicated cataract surgery and its relationship with normal conjuctival organisms. Setting: Ophthalmology Department, La Fe Hospital, University of Valencia. Patients: Forty patients who had undergone cataract extraction using either ECCE, phacoemulsification or nucleus fracture methods. Results: Positive cultures of aqueous humour were obtained in 32.5% of cases. The most commonly isolated organism was Staphylococcus coagulase-negative. Only in 7.7% of cases was the microorganism found in the conjunctiva the same as that found in the anterior chamber. The inoculum size ranged between 20 and 160 colonies/ml. One of the case…