I got to share this with you all - scientists have succeeded in communicating with lucid dreamers in a sleep lab. This is beyond eye tracking to signal you are lucid. This is actually someone awake realtime communicating with someone who is lucid dreaming.
Here is the pdf of the full article.
https://www.cell.com/current-biology/pdfExtended/S0960-9822(21)00059-2
Or HTML if you prefer
Real-time dialogue between experimenters and dreamers during REM sleep