Search results for "Pupil"
showing 10 items of 181 documents
Objective health literacy skills among ninth graders in Finland : outcomes from a national learning assessment
2021
Background:Health literacy (HL) is an important determinant for maintaining and improving health throughout the lifespan. This underlines the need to monitor HL, including among adolescents, and to understand the factors explaining HL, with a view to decreasing differences in HL. The aim of this study was to objectively measure HL, and the relationship between HL and socio-demographic factors (gender, language of instruction, pupils’ educational aspirations, parents’ educational background and pupils’ school achievement) among pupils ( n = 3652) at the end of basic education in Finland.Methods:A nationally representative assessment, which included 55 items on HL, was conducted as a traditio…
BYSTANDERS IN THE SCHOOL VIOLENCE SITUATIONS FROM THE PUPIL PERSPECTIVE
2021
Bullying rarely takes place between two individuals in isolation, usually, it occurs with pupil’s bystanders present. How often pupils take the role of bystander, what bystanders usually do in the bullying situation and how it can be explained was examined with 5003 pupils attending 55 Latvia’s schools. Responses indicated that more than a third (n=1913) of all respondents admitted that they had been in a situation where they witnessed another pupil being bullied. After analyzing the responses of those respondents, was concluded that although the majority of pupils felt bad about it, most did nothing about it or did not consider the situation important for involvement. This could be explain…
Optical performance of two new trifocal intraocular lenses: through-focus modulation transfer function and influence of pupil size
2013
Background To compare the in vitro optical quality of two new trifocal intraocular lenses at different focal points as a function of pupil size. Methods Two intraocular lenses having different design approaches were evaluated: the AT LISA tri 839MP with a trifocal diffractive design, and the FineVision, which combines two distinct apodized bifocal diffractive profiles resulting in three foci. A PMTF optical bench was used to assess the intraocular lenses' performance, and as optical quality metrics, the through-focus modulation transfer function was selected; that is, it was measured at 10 focal points and for four different apertures (2.0, 3.0, 3.75 and 4.5 mm). Results For both lenses, th…
Back to Pupillometry: How Cortical Network State Fluctuations Tracked by Pupil Dynamics Could Explain Neural Signal Variability in Human Cognitive Ne…
2017
Visual Abstract
Optical quality of rotationally symmetrical contact lenses derived from their power profiles.
2017
To present a methodology for evaluating the optical quality of rotationally symmetrical contact lenses (CLs) from a single power profile.Simulated rotationally symmetrical power profiles corresponding to different CLs designs (monofocal, two-zone center-near bifocal, and four-zone center-distance bifocal) were used to calculate the wavefront error profile by means of numerical integration. Then, each lens wavefront error profile was spun around the center to obtain the lens wavefront error surface. From the surface, monochromatic optical transfer functions (OTF), simulated images and the visual Strehl ratio based on the OTF (VSOTF) were obtained for different distances and pupil sizes (3 an…
Correlation between optics quality of multifocal intraocular lenses and visual acuity
2009
Purpose To study the relationship between the optics quality of multifocal intraocular lenses (IOLs) and distance-corrected near, intermediate, and distance visual acuity to determine the degree to which optics quality must change to produce a significant difference in visual acuity. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods Monocular distance-corrected visual acuity (decimal and logMAR) was measured at 4 m, 70 cm, and 30 cm under photopic and mesopic conditions in eyes with 1 of 3 multifocal IOL models. Visual acuity versus the “average modulation” of the IOL was assessed. Results The pupil diameter and patient age were similar between the 3 IOL groups (20 …
A new technique to determine vertical dimension of occlusion from anthropometric measurement of interpupillary distance
2014
Background: A number of techniques are being practiced for the evaluation of VDO, but none of them is scientifically more accurate than other. Each method advocated has its own limitations. Objectives: The purpose of this study was to find correlation between vertical dimension of occlusion (VDO) and interpupillary distance (IPD). Material and Methods: A cross-sectional study was conducted on 400 dentate subjects comprising of 200 males and 200 females. Anthropometric measurement of VDO was recorded clinically using modified digital vernier caliper. Also, a standardized digital photograph of face was generated from the frontal aspect using a digital camera for the measurement of IPD in mill…
Modulation transfer function: Rigid versus foldable phakic intraocular lenses
2008
Purpose To study in a standard eye model the changes in modulation transfer function (MTF) of a monofocal intraocular lens (IOL) when a phakic IOL (pIOL) is placed in the anterior chamber, compare the MTFs of the rigid Artisan pIOL and foldable Artiflex pIOL, and evaluate the temporal evolution of the MTF of the foldable pIOL after the mechanical stress the pIOL undergoes when injected. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods The MTF values of the IOLs were calculated from the cross-line spread function recorded with the Opal Vector System. The measurements were taken using an eye model following the British and EN-ISO standards with 2.0 mm, 3.0 mm, 4.0 mm…
The posterior chamber phakic refractive lens (PRL): a review
2012
Implantation of phakic intraocular lenses (pIOLs) is a reversible refractive procedure, preserving the patient’s accommodative function with minimal induction of higher order aberrations compared with corneal photoablative procedures. Despite this, as an intraocular procedure, it has potential risks such as cataracts, chronic uveitis, pupil ovalization, corneal endothelial cell loss, pigmentary dispersion syndrome, pupillary block glaucoma, astigmatism, or endophthalmitis. Currently, only two models of posterior chamber pIOLs are commercially available, the implantable collammer lens (STAAR Surgical Co.) and the phakic refractive lens (PRL; Zeiss Meditec). The number of published reports on…
Cantor Dust Zone Plates
2013
In this paper we use the Cantor Dust to design zone plates based on a two-dimensional fractal for the first time. The pupil function that defines the coined Cantor Dust Zone Plates (CDZPs) can be written as a combination of rectangle functions. Thus CDZPs can be considered as photon sieves with rectangular holes. The axial irradiances produced by CDZPs of different fractal orders are obtained analitically and experimentally, analyzing the influence of the fractality. The transverse irradiance patterns generated by this kind of zone plates has been also investigated.