Search results for "Vision test"
showing 10 items of 25 documents
Effect of Decentration on the Optical Quality of Two Intraocular Lenses
2016
To analyze the effect of decentration on the optical quality of two diffractive-refractive intraocular lenses, a bifocal and a trifocal, when displaced laterally (horizontal direction) from the center.The AT LISA 809M IOL (+3.75 D add) with two main foci and the AT LISA tri 839MP intraocular lens with three main foci (Carl Zeiss Meditec AG, Jena, Germany) were analyzed. The optical quality of the intraocular lenses was measured with the PMTF (power and modulation transfer function [MTF] measurement for refractive and diffractive intraocular lenses) optical bench (Lambda-X, Nivelles, Belgium). The optical quality of the lenses was evaluated by the MTF at different object vergences, the avera…
No Benefit of a Pediatric Screening in Discovering Reduced Visual Acuity in Children: Experiences from a Cross-Sectional Study in Germany
2020
Background: The newly introduced German pediatric screening examination at the end of the third year of life (U7a) incorporates visual function testing in particular
Comparison of myopic progression in Finnish and Singaporean children
2020
Purpose To compare 3-year myopic progression between Finnish and Singaporean children. Methods Myopic progression was compared between 9-year-old (mean age 9.7 ± 0.4 years, n = 92) and 11-year-old (mean age 11.7 ± 0.4 years, n = 144) Finnish (Finnish RCT) children and Singaporean children matched by age and refraction (SCORMMatched, n = 403) and 7- to 8-year-old Singaporean children matched only by refraction (SCORM Young, n = 186). Spherical equivalent (SE) was between −0.50 and −3.00 D. Refraction with cycloplegia was controlled annually for 3 years. Information on parental myopia, mother’s education, time spent on near-work and outdoor time was gathered by parental questionnaire. Results…
Stereoacuity with balanced presbyopic contact lenses.
2010
Our aim was to evaluate near stereoacuity with the balanced Proclear Multifocal simultaneous vision contact lens. Twenty-five presbyopic subjects were fitted binocularly with the Proclear Multifocal contact lens and with distance contact lenses combined with reading spectacles, which served as controls. After one month, stereoacuity was measured using the vectographic Titmus and Random dot stereotests and the Howard-Dolman (HD) apparatus under photopic conditions (85 cd/m(2) ) at 40 cm. Binocular high-contrast visual acuities (BHCVA) at distance and near were examined. For the multifocal group, mean stereoacuity with the Howard-Dolman method was 22.40 ± 8.23 seconds of arc. Using the Titmus…
Stereoacuity with simultaneous vision multifocal contact lenses.
2010
Our purpose was to evaluate near stereoacuity (SA) with Focus Progressives and PureVision Multifocal simultaneous vision contact lenses. In a cross-over study design, 20 presbyopic subjects were fitted with either the Focus Progressives or PureVision Multifocal lenses. After 1 month, SA was measured with the vectographic Titmus, Random dot stereotests, and the Howard-Dolman apparatus under photopic conditions (85 lux) at 40 cm. Binocular high-contrast visual acuity at distance and near was examined. Subjects were then refitted with the alternative correction and the procedure was repeated. Mean SA with the Focus Progressive was 21 +/- 7 sec arc, 54 +/- 17 sec arc, and 51 +/- 21 sec arc, wit…
Technical Report: Repeatability of Contrast Sensitivity Test in Children
2020
Contrast sensitivity (CS) in children is not routinely measured in the clinical setting, although CS losses have been found in amblyopic and premature children. Thus simple visual acuity measurements do not completely assess their quality of vision. To evaluate contrast sensitivity in children, a reliable and easy test, sampling the entire spatial frequency range, is necessary. Purpose This study aimed to evaluate the repeatability and normal range of the contrast sensitivity function measured using the Topcon CC-100 instrument, in children aged between 4 and 9 years, for use as a diagnostic tool. Methods Contrast sensitivity was measured in 25 children, 11 boys and 14 girls, with normal or…
Factors influencing myopic shift in children after intraocular lens implantation.
2019
Introduction:Intraocular lenses have always been a controversial topic in pediatric cataract surgery. In the early 1990s in the post-Soviet states of Eastern Europe, intraocular lenses promised an easier full-time correction and amblyopia treatment. Since 1991, ophthalmologists in Latvia have been implanting intraocular lenses in infants. Amount of the postoperative myopic shift and its influencing factors, analyzed in this article, are important indicators of congenital cataract treatment.Materials and methods:A retrospective chart review off 85 children (137 eyes) who underwent foldable posterior chamber intraocular lens implantation at the Clinical University Hospital in Riga, Latvia, fr…
Effect of sport-tinted contact lenses for contrast enhancement on retinal straylight measurements
2008
PURPOSE: To investigate the effect of two tinted contact lenses (CL) designed for outdoor sports activity on the psychometric determination of retinal straylight using the compensation comparison method. METHODS: Thirteen emmetropic subjects were randomly fitted with two different tinted Nike Maxsight (Bausch & Lomb, Rochester, NY, USA) CL in one eye, while the contralateral eye was fitted with a clear lens made of the same material (Optima 38, Bausch & Lomb). Three valid straylight measurements were taken on each eye before and a few minutes after lens insertion, when lens stabilization had occurred. RESULTS: The subjects' mean straylight values were 0.90 +/- 0.09 at baseline and 0.95 +/- …
The stenopaeic slit: an analytical expression to quantify its optical effects in front of an astigmatic eye.
2001
The stenopaeic slit is a trial case accessory used in subjective refraction, especially when high astigmatism is present. In spite of its simplicity, the effect of the slit when it is not oriented along one of the principal meridians of the examined eye is difficult to predict, even in terms of classical geometrical optics. In this paper, the optical principles of the slit are considered with full details in the theoretical framework of the dioptric power space. An analytical expression to obtain the residual refractive error when a stenopaeic slit is placed in front of an astigmatic eye at any orientation is deduced. In the light of these results, some aspects of the clinical procedure are…
Technologies supporting vision screening: a protocol for a scoping review
2021
Introduction Vision problems affect academic performance, social and mental health. Most traditional vision screening methods rely on human expert assessments based on a set of vision tests. As technology advances, new instruments and computerised tools are available for complementing vision screening. The scoping review based on this protocol aims to investigate current technologies for vision screening, what vision tests can be complemented by technologies, and how these can support vision screening by providing measurements. Methods and analysis The planned review will utilise the PRISMA extension for Scoping Reviews (PRISMA-ScR) tool. Electronic search will be performed in databases, i…