Publications [#186536] of Yakir Gagnon

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Published Abstracts

  1. Y. L. Gagnon, R. H. H. Kröger, B. Söderberg, Light Dispersion in the Lens of the Cichlid Fish Astatotilapia Burtoni, The Association for Research in Vision and Ophthalmology no. 4380 (2009) .
    (last updated on 2011/01/16)

    Abstract:
    Purpose: Dispersion has been studied in vertebrate eye tissues since the beginning of the 20th century. Different models describing this phenomenon can be found in the literature. We suggest a new model based on the combination of dispersion measurements with experimental results from laser-scanning, where the actual deflections of laser beams have been ray-traced through a fish lens. The model describes dispersion in vertebrate media in general and in fish lenses in particular, based on both the direct dispersion measurements of various vertebrate species' eye media and the laser-scanning results from fish lenses. Methods: Using a multi-objective goal attainment optimization algorithm, a model was fitted to dispersion measurements of various vertebrate species' eye media as well as to laser-scanning results from fish lenses. Sivak and Mandelman measured dispersion directly, for a multitude of vertebrate eye media, with an Abbe refractometer. Kröger and Campbell measured how differently colored thin laser beams were deflected by lenses of the African cichlid fish Astatotilapia burtoni. The dispersion model was optimized to fit both the measured dispersion and the measured deflections in the above mentioned studies. Results: A set of optimized parameters for the dispersion model was found. These describe the directly measured dispersion as well as the laser-scanning data with R square values (coefficients of determination) that equaled the ones calculated when the model was fitted to only one of the datasets. Conclusions: By optimizing the model to fit two different datasets, we further restricted the number of possible combinations of parameters that would yield satisfactory fits. This model describes the directly measured dispersion of vertebrate eye media and the observed ray-tracing laser scans made on similar media equally well.