As a countermeasure against rapidly expanding infectious diseases, it is becoming more important to obtain information on health conditions in a non-invasive, non-contact manner. Expectations are rising for health care devices that use optical technologies. Recent developments have lowered costs for light sources, image sensors, and photodetectors that support the visible, near-infrared, and mid-infrared regions as well as the development of low-cost high-precision bioanalysis systems based on light scattering and light absorption. This special issue introduces some health care devices that will imminently be put into practical use, those that have already been commercialized, and their social and technical backgrounds and measurement principles.