Eye in the sky is a term used by players and staff in land-based casinos; it refers to the numerous cameras used in casinos to monitor the action.
To prevent players from cheating and make sure that everything is functioning smoothly, every modern brick-and-mortar casino has an advanced surveillance system that tracks everything that’s going on. Cameras are located on the ceiling, which is why people refer to them as eyes in the sky.
In addition, the term may also be used to describe the casino’s security personnel. Usually, they are located in the control room that has a video feed from all the cameras, and they are the ones who notify the security “on the ground” in case there is something suspicious going on.
Earlier casinos had dated monitoring equipment, but some of the best-equipped casinos of today have advanced high-resolution cameras capable of recording audio as well.