Split diopter shots are most often attributed to Brian De Palma but director Robert Wise incorporated them into many of his films as a visual style and storytelling device, often using them more than 100 times in one film.
A Split Focus Diopter is half convex glass that attaches in front of the camera’s main lens to make half the lens nearsighted. The lens can focus on a plane in the background and the diopter on a foreground element.