Search results for "Contrast"
showing 10 items of 1162 documents
Short-Term Changes in Light Distortion in Orthokeratology Subjects
2015
Purpose. Quantifying adaptation to light distortion of subjects undergoing orthokeratology (OK) for myopia during the first month of treatment. Methods. Twenty-nine healthy volunteers (age: 22.34 ± 8.08 years) with mean spherical equivalent refractive error −2.10 ± 0.93D were evaluated at baseline and days 1, 7, 15, and 30 of OK treatment. Light distortion was determined using an experimental prototype. Corneal aberrations were derived from corneal topography for different pupil sizes. Contrast sensitivity function (CSF) was analyzed for frequencies of 1.50, 2.12, 3.00, 4.24, 6.00, 8.49, 12.00, 16.97, and 24.00 cpd under photopic conditions. Results. Average monocular values of all light di…
Corneal Aberrations, Contrast Sensitivity, and Light Distortion in Orthokeratology Patients: 1-Year Results.
2016
Purpose. To evaluate the corneal higher-order aberrations (HOA), contrast sensitivity function (CSF), and light distortion (LD) in patients undergoing orthokeratology (OK). Methods. Twenty healthy subjects (mean age: 21.40 ± 8 years) with mean spherical equivalent refractive error M = −2.19 ± 0.97 D were evaluated at 1 day, 1 month, and 1 year after starting OK treatment. Monocular LD, photopic monocular CSF, and corneal HOA for 6 mm pupil size were measured. Results. LD showed an increase after the first night (𝑝 0.05). Spherical-like, coma-like, and secondary astigmatism HOA RMS increased significantly (𝑝 ≤ 0.022) from baseline to 1-month visit, remaining unchanged over the follow-up. C…
Contrast sensitivity after refractive lens exchange with diffractive multifocal intraocular lens implantation in hyperopic eyes
2008
Contrast Test chart at distance and near under 3 luminance levels (85.0 cd/m 2 , 5.0 cd/m 2 , and 2.5 cd/m 2 ) before and after RLE with bilateral AcrySof ReSTOR IOL implantation in 30 hyperopic eyes with presbyopia and low astigmatism (%1.0 diopter). Results after surgery were compared with those before surgery. RESULTS: Six months postoperatively, the mean residual spherical equivalent refractive error was 0.21 diopter G 0.19 (SD). The best corrected distance and near visual acuities were comparable to those before surgery. For distance vision, the safety index was 1.02 and the efficacy index was 0.91. For near vision, the values were 1.04 and 1.02, respectively. There were no statistical…
Estadística (Estadística Inferencial en Psicología) (2010/2011)
2010
La asignatura Estadística es una asignatura troncal de carácter anual que se imparte en el 1er curso del grado en Psicología, y consta de un total de 12 créditos. La finalidad general de la asignatura es la de proveer procedimientos para dar respuesta a las cuestiones de interés para los psicólogos mediante análisis estadístico de datos, y en consecuencia tiene un carácter teórico-práctico.
Eine Nierenfunktionsanalyse durch die Computertomographie
1992
The CT clearance in a number of urological patients (39 patients, 25 with normal renal function) was studied by means of an "area under curve" (AUC) method, using a region of interest. 31 patients were given meglumine ioxithalamate and 8 patients Iopamidol as a contrast medium. Both for total and partial function there was highly significant correlation with isotope clearance with good reproducibility. The difference in the pharmacokinetics of the contrast media affected the absolute clearance values.
Keratoconus apex positions impact on visual acuity and contrast sensitivity
2020
The change of corneal shape in keratoconus subjects can impact the optical quality of the eye on the retina and it reduces the contrast sensitivity by light scattering. The aim of our study was to estimate the keratoconus subjects’ contrast sensitivity and visual acuity depending on keratoconus apex position. We included 45 keratoconus subjects (77 eyes), which have keratoconus in the first to the third stage, in our study. There were 33 eyes with keratoconus apex in the central part of the cornea and 46 eyes with keratoconus apex in the periphery of the cornea. Contrast sensitivity and visual acuity were measured at 3 m with and without the best possible spectacle correction using the FrAC…
Visual motion integration controls attractiveness of objects in walking flies and a mobile robot
2008
Walking fruit flies are attracted by near-by objects. They estimate the distance to these objects by the parallax motion of their images on the retina. Here we provide evidence from robot simulations that distance is assessed by motion integration over large parts of the visual field and time periods of 0.5 s to 2 s. The process in flies is not selective to image motion created by the self-motion of the fly but also sensitive to object motion and to the pattern contrast of objects. Added visual motion (e.g. oscillations) makes objects more attractive than their stationary counterparts. Front-to-back motion, the natural parallax motion on the eyes of a forward-translating fly, is preferred. …
Images perceived after chromatic or achromatic contrast sensitivity losses.
2010
Purpose. We simulate how subjects with losses in chromatic and achromatic contrast sensitivity perceive colored images by using the spatiochromatic corresponding pair algorithm. Methods. This is a generalized version of the algorithm by Capilla et al. (J Opt Soc Am (A) 2004;21:176 –186) for simulating color perception of color deviant subjects, which incorporates a simple spatial vision model, consisting of a linear filtering stage, with a band-pass achromatic filter and two low-pass chromatic ones, for the red-green and blue-yellow mechanisms. These filters, except for the global scaling, are the subject’s contrast sensitivity functions measured along the cardinal directions of the color s…
Synergistic effects of childhood adversity and polygenic risk in first-episode psychosis
2023
The European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) Project is funded by grant agreement HEALTH-F2-2010-241909 (Project EU-GEI) from the European Community’s Seventh Framework Programme.
Sastatāmā un lietišķā valodniecība: Kontrastīvie pētījumi.10
2001
Krājuma rakstu autori analizē dažādu valodas līmeņu parādības angļu, latviešu, lietuviešu, krievu, norvēģu valodā un tulkojumos.Valodu sastatījums veikts kā strukturālā, tā arī funkcionālā un kultūrvēsturiskā aspektā. Atklātas šo valodu īpatnības, arī to kopīgās īpašības. Vairāki raksti veltīti pedagoģijas problēmām. Aplūkota arī valodu vienību mijiedarbība gan valodu kontaktu, gan tulkošanas procesā.