Search for dissertations about: "Refractive error"

Showing result 1 - 5 of 13 swedish dissertations containing the words Refractive error.

  2. 1. Prevalence of refractive errors and incidence of myopia in Swedish schoolchildren

    Author : Pelsin Demir; António Filipe Macedo; Karthikeyan Baskaran; Niall Strang; Linnéuniversitetet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Refractive error; myopia; prevalence; incidence; risk factors; children; fovea; macula; autorefractor; aberrometer; synfel; refraktion; myopi; barn; prevalens; incidens; riskfaktorer; fovea; makula; autorefractor; aberrometer; Optometry; Optometri;

    Abstract : PurposeThe aim of this thesis was to investigate the prevalence, incidence, and risk factors for myopia development in a cohort of Swedish schoolchildren. The specific goals were: - to recruit a cohort of children aged 8 to 16 years and to follow the cohort over a period of 24 months with regular study visits; - to investigate the predictive value of relative peripheral error and other optical parameters for the prevalence and incidence of myopia; - to determine and investigate the predictive value of genetic and environmental factors, and structural characteristics of the eye to the incidence of myopia. READ MORE

  4. 2. A multi-prism lens for hard X-Rays

    Author : Björn Cederström; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; x-ray; optics; refractive; lens; mammography; synchrotron; Physics; Fysik;

    Abstract : This thesis describes a new type of refractive lens for hardx-rays. It is shown that a linear array of prisms, slightlyinclined with respect to the optical axis, will form a linefocus at a certain distance from the lens. Hence, the namemulti-prism lens. READ MORE

  5. 3. A Two-stage Numerical Procedure for an Inverse Scattering Problem

    Author : John Bondestam Malmberg; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; coefficient inverse problem; inverse scattering; backscattering data; approximate global convergence; finite element method; adaptivity; a posteriori error analysis; a posteriori error analysis;

    Abstract : In this thesis we study a numerical procedure for the solution of the inverse problem of reconstructing location, shape and material properties (in particular refractive indices) of scatterers located in a known background medium. The data consist of time-resolved backscattered radar signals from a single source position. READ MORE

  6. 4. Digital speckle photography and digital holography for the study of transparent media

    Author : Eva-Lena Johansson; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Experimentell mekanik; Experimental Mechanics;

    Abstract : In the fields of combustion and fluid mechanics, temperature- and density fields are of interest to measure. Optical measurement methods may be used to study such transparent media. Flames, gases and liquids are examples of transparent media, often called phase objects in an optical context. READ MORE

  7. 5. Wavefront Aberrations and Peripheral Vision

    Author : Linda Lundström; Peter Unsbo; Austin Roorda; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Optics; Human eye; Aberrations; Peripheral vision; Central visual field loss; Optics; Optik;

    Abstract : Failing eyesight causes a dramatic change in life. The aim of this project is to help people with large central visual field loss to better utilize their remaining vision. Central visual field loss means that the person has to rely on peripheral vision since the direct vision is lost, often due to a dysfunctional macula. READ MORE