The Hungarian physician Botond Roska has set himself the goal of restoring sight to the blind. Roska has tracked down the approximately one hundred different cell types in the retina and investigated their interaction. Now the scientist is working on making these fundamental insights beneficial for patients and alleviating or curing their diseases. Roska achieved a breakthrough when he reprogrammed a cell type in the eye, enabling it to take over the function of defective light receptor cells. He was thus able to make blind retinas light-sensitive again. Clinical trials with blind people have already begun. Botond Roska has been awarded the Körber Prize for European Science 2020 for his research.