I worked on developing, mnaufacturing, and distributing vein visualization tools for over 12 years. So I have talked about the technology a lot. These product are an excellent example of projection augmented reality.
While the story sounds simple, “Having a hard time finding a vein? Use a simple vein visualization tool to help you visualize the veins in your arm.”, it is not as simple as it sounds.
Even if the device can image the veins well one of the big challenges is what things look like after projection. This is a general problem with all AR projection devices. The image is not the same as what you see with your eyes.