Carotenoids play important roles as antioxidants, blue light filter, and metabolic precursors of vitamin A in many physiological processes. Setting the stage for future research across diverse animal groups, I identified the first genes devoted to carotenoid metabolism and modification in Drosophila. I showed that the fly’s ninaB gene is essential for visual chromophore synthesis from carotenoids and encodes the long-sought after vitamin A forming enzyme. Additionally, I identified the first protein involved in membrane transport of lipophilic vitamins, NinaD. Subsequently, homologous proteins were shown to have similar functions in mammals, including humans, in my and many other laboratories. My current research focuses on the question how carotenoid and vitamin A homeostasis is maintained in the physiological state and how disturbances in this process contribute to blinding disease states. For these studies, my laboratory has established a wealth of animal models, reagents, techniques, and analytical tools. A better understanding of the molecular factors which control carotenoid and retinoid homeostasis will aid in the development of pharmacological and nutritional intervention strategies to combat blinding diseases, including vitamin A deficiency related disorders.