It's an increasingly common sight in hospitals around the world: a nurse measures our height, weight, blood pressure, and attaches a glowing plastic clip to our finger. Suddenly, a digital screen reads out the oxygen level in our bloodstream. How did that happen? Sajan Saini shows how pairing light with integrated photonics is leading to new medical technologies and less invasive diagnostic tools. [Directed by Artrake Studio, narrated by Addison Anderson].