Pupil tracking is in consumer VR devices, I can see it being further miniaturized, especially with advances in waveguiding. In fact, this might be a great use

Pupil tracking is in consumer VR devices, I can see it being further miniaturized, especially with advances in waveguiding. In fact, this might be a great use for Zeiss's holocam tech [0]: high resolution, low definition, grayscale "window" that waveguides some of the light passing through, down to one of the edges, where an image sensor picks it up and decides it. 0: https://news.ycombinator.com/item?id=38881981 https://news.ycombinator.com/item?id=38881981