Eyes are one of the most complex organs found in animals. Through evolution the eyes of animals have evolved to suit some needs better than others. Some animals can see the world in 3D, while some others can see in the dark. Animals living in places where the light doesn’t reach like caves, can’t use their eye and hence have primitive eyes. Researchers from Institute for Stem Cell Biology and Regenerative Medicine, study the pit eye seen in the flatworm Planaria to understand how the organism senses the environment around it.