Search results for "vision."
showing 10 items of 4900 documents
Changes in colour discrimination during the menstrual cycle.
2006
A group of normal women of reproductive age were recruited to investigate colour discrimination during the various phases of the menstrual cycle. Colour vision was tested with the Farnsworth-Munsell 100-hue arrangement test, and the test was administered at 3 time points: the beginning of the cycle, ovulation, and the end of the cycle. We found that colour discrimination was better at ovulation than at the other 2 time points. It is possible that psychological as well as hormonal factors could contribute to improved colour vision performance at ovulation.
Simulating Images Seen by Patients with Inhomogeneous Sensitivity Losses
2012
PURPOSE We aim to simulate how colored images are perceived by subjects with local achromatic and chromatic contrast sensitivity losses in the visual field (VF). METHODS The spatiochromatic corresponding pair algorithm, introduced in a previous article (J Opt Soc Am (A) 2004;21:176-186), has been implemented with a linear model of the visual system. Spatial information is processed separately by the chromatic and achromatic mechanisms by means of a multiscale model, with sensors selective to frequency, orientation, and spatial position, whose mechanism-dependent relative weights change with the spatial location of the image. These weights have been obtained from perimetric data from a patie…
Macular edema computer-aided evaluation in ocular vein occlusions.
1998
This paper is concerned with the use of digital fundus imaging to detect, quantify, and follow up macular angiographic leakage due to retinal vein occlusions. Images were matched automatically. We detected those pixels with a high increment in gray level within the closest area to the foveal center. Binary images displaying leakage were obtained. The procedure was checked against two observers' agreement. Twenty-one angiographic studies were collected. Two images of each sequence were selected for digitalization. Numerical descriptors of the leakage were proposed and quantification plots were designed for each pair of images. Interobserver concordance ranged between 82 and 98% when manually…
Visual performance with simultaneous vision multifocal contact lenses.
2011
Purpose: The aim was to assess visual performance after PureVision high addition multifocal contact lens (PM) fitting through contrast sensitivity measured under different illumination levels for both distance and near. Methods: In a cross-over study, 20 presbyopic patients were randomly assigned to PM or spectacles. Near contrast sensitivity was measured with the Vistech VCTS 6500 system. Distance contrast sensitivity and distance visual acuity (VA) were measured with the Functional Vision Analyser under photopic (85 cd/m2) and mesopic (3.0 cd/m2) conditions, the latter also under two levels of induced glare: 1.0 lux and 28 lux. Near VA was measured by logMAR charts under approximately 8…
The impact of exposure to images of ideally thin models in TV commercials on eating behavior: an experimental study with women diagnosed with bulimia…
2011
This study investigates whether eating behavior in women with diagnosed bulimia nervosa is influenced by prior exposure to images of ideally thin models. Twenty-six participants diagnosed with bulimia nervosa (BN) and 30 normal controls (NC) were exposed to body-related and neutral TV commercials; then food that typically triggers binge eating was provided, and the amount of food eaten was measured. No significant difference for food intake between NC and BN could be found, but food intake for BN was predicted by the degree of thoughts related to eating behaviors during exposure to the thin ideal. No impact of general body image or eating pathology on food intake could be found. The results…
Storage of human oocytes in the vapor phase of nitrogen
2009
Objective To evaluate the effectiveness of long-term vapor-phase nitrogen storage of vitrified human oocytes as a strategy for preventing the risk of cross-contamination due to direct contact with the liquid nitrogen (LN). Design Prospective randomized study. Setting Private infertility center, IVI, Valencia. Patient(s) Oocyte donors (n = 44) and recipients (n = 46). Intervention(s) Vitrification by the Cryotop method. Storage of vitrified oocytes in a vapor-phase nitrogen storage freezer and a traditional LN storage tank. Donation of the surviving oocytes and evaluation of fertilization, embryo development, and clinical results. Main Outcome Measure(s) Survival, fertilization, and cleavage…
Complications following the use of alloplastic materials in urogynecological surgery
2011
Abstract Study design 118 patients, who were admitted from 2005 to 2008 to our department due to complications following mesh implantation, were included in a retrospective survey. We investigated patient symptoms, findings and subsequent patient management. There was a re-evaluation of symptoms in a follow-up eight weeks after the revision procedure. Data from our urogynecological file archive were used. Results The main complaints were de novo urgency, pain and recurrent urinary tract infections. The main findings were mesh erosion and infections including abscess formations and osteomyelitis. Before being admitted to our department, 42 patients (35.6%) had already undergone at least one …
Prevalence of general binocular dysfunctions in a population of university students.
1997
Although some authors report that the prevalence of general binocular dysfunctions (nonstrabismic) for nonpresbyopes in the clinical population is greater than any condition except refractive error, limited research is available to support this statement. This clinical study determined the presence and clinical implications of these conditions in a population of university students with heavy near visual demands.From a group of second year students who were given a thorough eye examination, 65 students were selected. The criteria for selection were the absence of significant uncorrected refractive error, healthy eyes, and no strabismus or amblyopia.32.3% of the subjects showed general binoc…
The effect of simulated normal and amblyopic higher-order aberrations on visual performance.
2012
Purpose To study the effect of simulated amblyopic and normal higher-order aberrations on visual performance of normal eyes. Methods To assess visual function, an adaptive optics visual simulator was used to compensate volunteers' ocular aberrations and simulate the wavefront aberration patterns found in healthy and amblyopic eyes in 7 healthy individuals. Visual acuity for high (100%), medium (50%), and low (10%) contrast and contrast sensitivity at 10, 20, and 25 cycles per degree (cpd) were measured after simulation of both pattern aberrations. The modulation transfer function and the point spread function were computed based on the aberration data. All measures were taken for 3 and 5.5 …
Chromatic and achromatic visual fields in relation to choroidal thickness in patients with high myopia: A pilot study
2018
Purpose. - To analyse the relationship between the choroidal thickness and the visual perception of patients with high myopia but without retinal damage. Methods. - All patients underwent ophthalmic evaluation including a slit lamp examination and dilated ophthalmoscopy, subjective refraction, best corrected visual acuity, axial length, optical coherence tomography, contrast sensitivity function and sensitivity of the visual pathways. Results. - We included eleven eyes of subjects with high myopia. There are statistical correlations between choroidal thickness and almost all the contrast sensitivity values. The sensitivity of magnocellular and koniocellular pathways is the most affected, an…