Search results for "Lens"
showing 10 items of 948 documents
Contrast sensitivity perimetry tests along the cardinal directions in color space: Correlation with the properties of the neural mechanisms mediating…
2014
It is well-known the advantages of measuring chromatic and achromatic contrast sensitivity for detecting pathologies. But these measurements are rarely used in clinical practice, due the complexity of the measurements and the examinator specialization. In fact, there is not a complete characterization of the response of the visual pathways to achromatic and chromatic spatio-temporal frequency stimuli. We have designed a new experimental device that facilitates these measurements and allow us to characterize the visual response in healthy patients. In this paper, we evaluated the responses of the visual pathways in healthy patients.
Multispectral analysis and cone signal modelling of pseudoisochromatic test plates
2013
The aim of the study is to determine the consistency of the desired colour reproduction of the stimuli using calibrated printing technology available to anyone (EpsonStylus Pro 7800 printer was). 24 colour vision assessment plates created in the University of Latvia were analysed right after their fabrication on august 2012 and after intense use for 7 months (colour vision screening on 700 people). Multispectral imagery results indicate that the alignment of the samples after seven months of use has maintained on the CIExy confusion lines of deutan deficiency type, but the shift towards achromatic area in the diagram indicate decrease in the total colour difference (ΔE*ab) of test backgroun…
Estimation of the mechanical properties of the eye through the study of its vibrational modes.
2017
Measuring the eye's mechanical properties in vivo and with minimally invasive techniques can be the key for individualized solutions to a number of eye pathologies. The development of such techniques largely relies on a computational modelling of the eyeball and, it optimally requires the synergic interplay between experimentation and numerical simulation. In Astrophysics and Geophysics the remote measurement of structural properties of the systems of their realm is performed on the basis of (helio-)seismic techniques. As a biomechanical system, the eyeball possesses normal vibrational modes encompassing rich information about its structure and mechanical properties. However, the integral a…
Multifokale Intraokularlinsen
2001
Modern cataract surgery has developed tremendously during the past 10-15 years. Improved surgical techniques, as well as improved implant materials and designs, have enlarged patient profiles and indications for cataract surgery. This also created much higher expectations from the patients' site. The loss of accommodation is loss of quality of life for presbyopic and especially young pseudophakic patients. Therefore cataract surgery with multifocal IOL implantation is not only of academic interest, but reflects demands and expectations of our patients. Multifocal IOLs have been implanted since 1986, starting with 2-3 zone refractive and diffractive designs. Due to surgical techniques of tha…
Binocular vision alterations after refractive and cataract surgery: a review.
2018
To review binocular and accommodative disorders documented after corneal or intraocular refractive surgery, in normal healthy prepresbyopic patients. A bibliographic revision was performed; it included works published before 1st July 2017 where accommodation and/or binocularity was assessed following any type of refractive surgical procedure. The search in Pubmed yielded 1273 papers, 95 of which fulfilled the inclusion criteria. Few publications reporting binocular vision and/or accommodative changes after refractive surgery in normal subjects were found. The reduction in fusional vergence is the most frequently reported alteration. Anisometropia is an important risk factor for postoperativ…
Spectroscopic capture of 1 Hz volcanic SO2fluxes and integration with volcano geophysical data
2009
[1] Here we present a novel spectroscopic approach to capturing, with unprecedented time resolution and accuracy, volcanic SO2 fluxes. This is based on two USB2000 spectrometers, coupled to cylindrical lens telescopes, each collecting light which has transited horizontal sections of the rising plume. We report on field data from Stromboli volcano, in which the entire emission rate from the volcano was measured, as well as flux signatures associated with individual crater explosions. The latter were integrated with seismic and thermal data, demonstrating correlations in both cases, and representing the first such geophysical-geochemical data corroboration on this timescale. Such a holistic e…
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…
Endothelial cells loss to the hyperopic pacients during phacoemulsification
2018
Introduction The phacoemulsification cataract surgery is the most frequently performed surgery and it generally improves vision in over 90% of the patients. Hyperopic patients are a challenge during phacoemulsification especially because of their short eyeball and shallow anterior chamber. A shallow anterior chamber is associated with overall reduction of the safe zone, which may lead to difficulty in creating the corneal incisions, harder capsulorhexis performing, or endothelial complications. Purpose The aim of the study was to present the endothelial cells loss after the phacoemulsification procedure in the hyperopic patients. Material and methods A number of 1775 patients operated in th…
"No mikä siinä muuttuu, äitiys vai yhteiskunta?" : äitiys arjen kokemuksena postmodernissa yhteiskunnassa
2014
Pro Gradu -tutkielmani ensisijaisena tarkoituksena on ollut selvittää, millaista on olla äiti nykyajan yhteiskunnassa, jossa äitiin ja äitiyteen kohdistuu monia ristiriitaisia odotuksia ja vaatimuksia. Toiseksi olen selvittänyt, miten äitiyttä ja äitiyden identiteettiä rakennetaan arjen käytännöissä ja näihin läheisesti liittyvänä kolmantena tehtävänä olen tarkastellut, millaiset perheeseen ja yhteiskuntaan liittyvät tekijät vetävät äitiä eri suuntiin eli tekevät äitiydestä ambivalenttia. Tutkimuskohteenani ovat työssäkäyvät 1–4 -vuotiaiden lasten äidit kahden vanhemman pikkulapsiperheistä. Lähestymistapani tutkimukseen on narratiivinen. Tavoitteenani on ollut saada äitien ääni kuuluviin. T…