Search for dissertations about: "Multifocal Lens"

Showing result 1 - 5 of 6 swedish dissertations containing the words Multifocal Lens.

  1. 1. MULTIFOCAL SPHERICAL FISH LENSES

    Author : Yakir Gagnon; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Multifocal Lens; Adaptation; Dispersion; Spherical lens; Model; Fish; Ray-trace; Longitudinal Chromatic Aberration; Longitudinal Spherical Aberration; Modulation Transfer Function; Point Spread Function; Refractive Index Gradient;

    Abstract : Vision is an important source of information for many animals. The lens plays a central role in the visual pathway and hence the ecology of these animals. Fish have spherically shaped crystalline lenses that contain a gradient of refractive index. Like all refracting elements, lens performance depends on the wavelength of the refracted light. READ MORE

  2. 2. Morphological and Physiological Adaptations in Cichlid Crystalline Lenses

    Author : Marcus Schartau; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; SKF-38393; D1-agonist; optical properties 6-hydroxydopamine; optical measurements; organ culture; dopamine; teleost; lens circulation; Lens; SCH-23390; melatonin; multifocal optical system;

    Abstract : Vertebrate eyes share a common ancestry as well as the basic design with a pupil, a retina and a lens. The lens is essential for perceiving the details in the world around us and ensures that a sharp image of the surroundings is focused onto the photoreceptors in the retina. READ MORE

  3. 3. Evolution of Vertebrate Eyes: a study on lens suspension and optical proterties

    Author : Ola Gustafsson; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; evolution; eye; fish; crystalline lens; lens suspension; multifocal optical systems; Agnatha; Actinopterygii; Chondrichthyes; Vertebrate; Sarcopterygii;

    Abstract : Many fishes have well-developed visual systems with color vision capabilities. The crystalline lens is the major refractive element in a fish eye since the cornea is optically inactive underwater. A typical fish eye has a large pupil and a lens of short focal length, features that increase light gathering ability. READ MORE

  4. 4. Ocular aberrations and visual quality in aspherical and multifocal contact lenses

    Author : Anna Lindskoog Pettersson; Karolinska Institutet; Karolinska Institutet; []
    Keywords : MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; Contact lenses;

    Abstract : Good visual quality and precise accommodation are required to be able to focus objects at distance and near, and are essential in order to be able to perform most tasks in life. Most eyes are not ideal eyes, i.e., they have different refractive errors which distort the produced image. READ MORE

  5. 5. Accommodation : clinical and theoretical investigations

    Author : Marika Wahlberg Ramsay; Karolinska Institutet; Karolinska Institutet; []
    Keywords : MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; Accommodative insufficiency;

    Abstract : Background: Accommodative insufficiency (AI) is a relatively common visual anomaly in children and young adults with an estimated prevalence of about 5%. Patients with AI usually suffer from blur, headaches and asthenopia associated with near work. READ MORE