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Prof. Ronald H.H. Kröger

I grew up in Hamburg, Germany, where I also got most of my educational training. My relation to Sweden began when I squeezed in a course at Linköping University in 1984. My scientific career started with work on cetaceans, which had been my dream since childhood. I did my MSc on cetacean behavior (supervisor: Jürgen Nicolai) and co-founded the European Cetacean Society. In 1989 I received a PhD from the University of Tübingen, Germany, for work on the optical properties of whale eyes performed at the Max-Planck Institute of Biological Cybernetics (supervisor: Kuno Kirschfeld). During my post-doc time at the Institute of Neuroscience, University of Oregon, USA, I started to work on developmental plasticity in the optical systems of eyes, using fish as the main model. In 1992 I joined the School of Optometry, University of Waterloo, Canada, as research fellow and continued this work. I went back to Germany in 1993 and worked at the Institute of Anatomy, University of Tübingen, until 1999. During this time my research was focused on developmental plasticity in the retina and its effects on color vision. Since 2000 I am member of the Lund Vision Group and was promoted to professor in 2005. For the discovery of multifocal lenses in animal eyes I received the Rank Prize for Opto-Electronics in 2004. Such lenses create well-focused color images in a previously unknown and highly efficient way. They are common in all major phylogenetic groups of vertebrates, from lampreys to primates.



My work is concerned with vision in vertebrates and I am especially fascinated by the crystalline lens of the eye. Because of its constitution of denucleated, apparently dead cells, the lens has long been regarded as a passive structure in the processes that fine-tune vision during development and to the daily light-dark cycle. This became unlikely, however, when the intricate optical function of multifocal lenses and their profound disadvantages for grayscale vision in dim light were understood. In the meantime, optical plasticity in the lens has become an established fact. My group studies the information transfer capabilities of multifocal lenses as well as how crystalline lenses grow and are optically optimized during development. We investigate also how lens and eye function change during ontogeny. Following the flow of visual information one step further, we study how the image on the retina is sampled by the photoreceptors. I am particularly interested in the differences between biological and technical solutions, having biomimetic applications in mind. Another path of putting our knowledge on fish vision to practical use is to develop visual stimuli for making fishing techniques more selective and less damaging to the marine environment.

In addition, we address questions concerning eye temperature regulation and its implications for visual performance. This is related to lens function, as mammalian lenses, but not fish lenses, develop reversible cataracts at low temperatures, and image sampling, as a cold eye is slower, but more sensitive than a warm eye. This interest in thermal sensory biology is related to my work in the Mammalian Rhinarium Group.



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Last modified 27 Jun 2013

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