After finishing a postdoctoral position at the Australian National University in Canberra in 1984, I started my own lab at Lund University where I earlier got my PhD. In 1990 I founded the Lund Vision Group and recruited Eric Warrant. Later recruitments were Almut Kelber and Ronald Kröger, who substantially added to the strength of the group. After yet further recruitments, the Lund Vision group grew and has now remained stable for more than 20 years at 5-8 principal investigators and about 40 people, forming a cheerful and creative research environment. The expertise covers most aspects of visual ecology and eye evolution across the entire animal kingdom.

For as long as I can remember physics has been the foundation of my understanding of the world we all live in. My early interest in biology was driven by a fascination that living things, particularly animals, so much resemble machines. The visual system is almost pure optics and electronics in a biological packing. It is a breath-taking experience to discover the enormous diversity of eye designs, and to realize how it has evolved to meet different demands in different animals.

After many years of research on insect and crustacean eyes I turned my focus to vision in various under-studied animal groups such as box jellyfish, fan worms, velvet worms and clams to develop our understanding of how eyes and vision evolved. More recently I have also put efforts into opening the new field of “computational visual ecology” to allow a general assessment of what eyes of different types and sizes can see under different conditions. An interesting outcome of this computational approach was that the extreme eye size (diameter 27 cm) of giant deep-sea squid is motivated mainly for spotting large predators (read sperm whales) in the darkness of the deep sea.

My current projects involve more work on eye evolution, but also various approaches to reveal what different animals are able to see in their natural habitats. We use special cameras to record what animals with different types of colour vision are able to see, and we use ray-tracing techniques to analyse visual acuity and simulate the image information that animal eyes pick up. With these techniques we can get very direct information on what the world looks like to any kind of animal, from flatworms to birds of prey. This in turn allows us to learn what eyes are used for and how visually guided behaviours have originated and evolved.

My latest research concerns the eyes of vertebrates, and here we now have new information that clearly points to the fact that we lost our original paired eyes more than 500 million years ago before we became vertebrates, and that new eyes evolved from an unpaired median eye (which still lives on as our pineal gland in the brain).

We have also developed a new technique for quantifying essential aspects of environmental light. The camera-based technique measures the light reaching the eye from the environment, and not the light illuminating the environment (as in Lux-measurements). We now have unique information about the light environment in over 1300 habitats from rain forests to deserts, from the aquatic and maritime to the alpine. We know how natural light varies during the day, at dusk, at night and at dawn, as well as between seasons and different weather conditions. Our measurements reveal the wavelength composition, the amount of visual contrast, and how these variables depend on the elevation angle. The method has wide applications from visual ecology to lighting and architecture, and offers the first quantitative comparison of the visual environment. 

Based on this, we are now unravelling an unexplored but important role for the visual system. Both humans and animals use their eyes to assess their surroundings. For the animals, this is required for them to find the right habitat and choose appropriate behaviors depending on the environment, time, weather and other factors. For us humans, it makes us want to engage in different activities depending on the weather and light conditions. It also has profound effects on what we perceive as beautiful environments where we would like to stay.