Magnetoretinographic measurement

Abstract

In the retina, electric current densities are generated by pigment epithelium, photo receptors and Muller cells from which only the current of the photo receptors is primarily influenced by light. Via secondary effects other current densities are also produced. These current densities are the sources of Electroretinograms and Magnetoretinograms. Bioelectric intra- and extracellular current densities can be detected in both electric and magnetic ways as implied by the names Electroretinography and Magnetoretinography. This thesis presents results of Magnetoretinographic measurements and their comparison with their corresponding electroretinograms accomplished at the Ragnar Granit Institute of Tampere University of Technology. The focus of the work was mainly to achieve the best detection configuration with maximum sensitivity in the measurements. measurements are executed in the presence of light flashes which lead to the stimulation of the retina. The theoretical part of the study include an overview of the physiology and electrophysiology of the human eye, the functioning of the eye, theoretical aspects of ERG & MRG. The instrumentation used during the measurement is also introduced. /Kir10