Since the cessation of lucid dreaming experience may be simulated and no different in terms of perception from a real exit, differences between the physical world and lucid dreaming world must be actively discerned. In other words, a practitioner must know how to determine whether a genuine lucid dreaming exit has occurred.
At present, only one experiment is known almost to guarantee an accurate result. lucid dreaming space cannot withstand prolonged close visual attention to the minute details of objects. Within several seconds of acute examination, shapes begin to distort, objects change color, produce smoke, melt, or morph in other ways.
After exiting lucid dreaming, look at a small object from a distance of four to six inches, and remain focused on it for 10 seconds. If the object does not change, a practitioner can be assured that the surroundings are reality. If an object is somehow distorted or askew, a practitioner knows that lucid dreaming is intact. The simplest option is to look at the tip of the finger since it is always close at hand. It is also possible to take a book and examine its text. Text in lucid dreaming will either blur or appear as alphabetical gibberish, or be full of incomprehensible symbols.