Search results for "Genetic Structures"
showing 10 items of 2107 documents
Contrast sensitivity of the visual system in speckle imagery
1994
The contrast sensitivity function (CSF) of the whole visual system is determined with the use of coherent diffuse illumination. This function provides supplementary data about the effect of speckle on the ability of the visual system to perceive the spatial information contained in an image. The results show that speckle not only prevents perception of the finest details (highest frequencies) but also reduces the visibility of lower frequencies (especially where contrast is low). The difference between the CSF's determined with and without speckle is quantitatively very important. And the ratio between the two CSF's is a measure of the retinal ability to perceive contrast in the presence of…
Metabolomics of the aqueous humor in the rat glaucoma model induced by a series of intracamerular sodium hyaluronate injection
2015
Glaucoma models are helpful to study disease characteristics and to design new therapeutic options. Metabolomic profiling approach have been used to elucidating the molecular characteristics of the aqueous humor. Juvenile male Wistar rats experimental (n = 15) and controls (n = 6) were used for these studies. Experimental rats received weekly intracamerular injection of 25 µl of sodium hyaluronate in the left eye and sterile saline solution in the right eye, consecutively for ten weeks. Rats were subjected to anterior/posterior eye segment examinations, intraocular pressure (IOP), and flash electroretinograms (ERG). The aqueous humor was collected at endpoints and analyzed by Nuclear Magnet…
Intrinsically determined cell death of developing cortical interneurons.
2009
The cell death of inhibitory neurons, which originate far from the cortical areas to which they migrate during embryonic development, is determined autonomously rather than by competition for trophic signals from other cell types. It has long been known that apoptosis, a form of programmed cell death, eliminates young cells from developing tissues. In the field of neurobiology, it is widely believed that developmental neuronal-cell death results from cellular competition for environmentally derived survival signals that selects for an optimally sized and properly wired population of neurons. This study of developmental cell death in the mouse cortex in vivo, in vitro and after transplantati…
Sex Differences in Feedback: Effects on Rod-and-Frame Performance
1979
It has been demonstrated that feedback is effective in changing rod-and-frame performance for women if given the opportunity to adjust the rod to the vertical repeatedly from the same starting position. It is also shown that the significant difference between males and females in the Rod-and-frame Test is carried by the large difference in the initial tilting position.
Age-related changes in the human visual system and prevalence of refractive conditions in patients attending an eye clinic.
2008
PURPOSE: To retrospectively report the trends of change in several parameters of the human visualsystem over a wide age range in patients attending an eye clinic. SETTING: University of Valencia, Valencia, Spain. METHODS: The clinical records of 2654 patients were retrospectively reviewed, and the age, sex, spherocylindrical refraction, visual acuity, keratometry, and intraocular pressure were obtained. Descriptive values for each parameter and the correlations with age and between different parameters were calculated. Vectorial components of refraction, including blur, were also derived from clinical refractive data and then analyzed. RESULTS: Several parameters changed significantly with …
No evidence for an association of plasma homocysteine levels and refractive error – Results from the population-based Gutenberg Health Study (GHS)
2020
Purpose There is a strong association between severe hyperhomocysteinemia and myopia. Thus we studied the hypothesis that even moderately increased levels of homocysteine (Hcy) might be a potentially treatable risk factor for myopia. Methods The Gutenberg Health Study (GHS) is a population-based, prospective, observational cohort study in Germany, including 15,010 participants aged between 35 and 74 at recruitment. The baseline examination was conducted from 2007–2012. Refraction was measured using autorefraction (HARK 599, Carl Zeiss AG, Jena, Germany). Hcy was measured by an immunoassay. We included only phakic participants without a history of corneal surgery or corneal laser treatment. …
Characteristics and pathologies of the vitreo‐macular interface—results from the Gutenberg Health Study
2019
Purpose We aimed to determine the prevalence of characteristics and pathologies of the vitreo-macular interface within the general population. Methods The Gutenberg Health Study is a population-based study in Germany, including an ophthalmological examination with refraction, biometry and optical coherence tomography (OCT) imaging. Characteristics of the vitreo-macular interface were graded on volume scans including visibility of an epiretinal membrane, full-thickness macular hole, lamellar hole and pseudohole. Overall and age-specific prevalences including 95% confidence intervals [95%-CI] were calculated. Association analyses were conducted to determine systemic and ocular factors that ar…
Genetic variants associated with human eye size are distinct from those conferring susceptibility to myopia
2021
Purpose: Emmetropization requires coordinated scaling of the major ocular components, corneal curvature and axial length. This coordination is achieved in part through a shared set of genetic variants that regulate eye size. Poorly coordinated scaling of corneal curvature and axial length results in refractive error. We tested the hypothesis that genetic variants regulating eye size in emmetropic eyes are distinct from those conferring susceptibility to refractive error.Methods: A genome-wide association study (GWAS) for corneal curvature in 22,180 adult emmetropic individuals was performed as a proxy for a GWAS for eye size. A polygenic score created using lead GWAS variants was tested for…
Relative Peripheral Myopia Induced by Fractal Contact Lenses
2018
[EN] Purpose: To assess the peripheral refraction induced by Fractal Contact Lenses (FCLs) in myopic eyes by means of a two-dimensional Relative Peripheral Refractive Error (RPRE) map. Materials and Methods: This study involved 26 myopic subjects ranging from -0.50 D to -7.00 D. FCLs prototypes were custom-manufactured and characterized. Corneal topographies were taken in order to assess correlations between corneal asphericity and lens decentration. Two-dimensional RPREs were measured with an open-field autorefractor at 67 points, covering the central 60 x 30 degrees of the visual field. The bidimensional RPRE vector components: M, J(0) and J(45) of the difference between the values obtain…
Working-Age Cataract Patients: Visual Results, Reading Performance, and Quality of Life with Three Diffractive Multifocal Intraocular Lenses
2013
Purpose To compare the visual outcomes, reading performance, and quality of life (QoL) of working-age cataractous patients bilaterally implanted with 3 different diffractive multifocal intraocular lenses (MIOLs). Design Two-center, randomized, prospective, double-masked study. Participants Sixty-three consecutive patients (126 eyes) seen at Ophthalmology Section, Palermo and Florence University, Italy, randomized to receive the ReSTOR SN6AD3 (Alcon Laboratories, Inc, Irvine, CA) (20 patients, group A), ReSTOR SN6AD1 (Alcon Laboratories, Inc) (21 patients, group B), or TECNIS ZMA00 (Abbott Medical Optics, Santa Ana, CA) (22 patients, group C) MIOL. Intervention Phacoemulsification. Main Outc…