Physics is directly related to various professions since it is fundamental science. Opticianry is one of such physics-related professions. This study, it was aimed to determine the conceptual understanding levels of opticians related to the concepts of light and optics which are directly related to their professions. In the study, which was conducted via the mixed method, the participants were determined with the convenient sampling method. A total of 203 opticians attended the study. Data were collected with the help of the Light and Optics Conceptual Evaluation Test in addition to the Open-Ended Questions and Concept Cartoons selected from the literature. As a result of the study, it was reached that the conceptual understanding levels of opticians were low with several misconceptions and insufficiencies related to the light and optics concepts. In the light of the findings, the importance of physics education for opticians was implied.