This directed case study explores the topic of color vision and its variations as experienced in humans. The case begins with a review of visual transduction from photons to recognition within the nervous system. The focus then shifts to an examination of genetic color vision deficiencies, a topic which is complicated by the fact that color vision is essentially an experienced phenomenon. Although the basic technical aspects of color vision can be grasped through the study of the activation of photoreceptors, variations in color vision are difficult to describe in terms other than differences in photoreceptor absorbency rates. In this case study, students explore the physiology, genetics, and evolution of color vision and how color vision deficiencies can be identified through real-world testing. The case is appropriate for use in courses that include an introductory level focus on physiology of special senses, including undergraduate anatomy and physiology, nursing, or a specialized undergraduate biology course, as well as appropriate honors high school classes.