I’m sure I saw this before
The phenomena of Deja Vu has tickled the sensation of researchers worldwide. In the scientific sense, deja vu is most likely NOT an act of precognition or prophecy but it is simply an anomaly of memory wherein an experience is being recalled or revisited. In most cases, researchers are not totally sure if this event already happened in the past. Those things remain uncertain. This is one of the theories that are being studied by researchers - memory.
Another theory that is being focused on is vision. As the theory states, one eye may possibly record what is seen fractionally by the other in a faster manner which therefore creates a strong recollection sensation on the same scene that is viewed a couple of milliseconds later by the opposite eye. If other sensory is involved, then it negates this vision theory.
The early researchers tried to place a link between deja vu and other neurotic disorders but they failed to establish this link. The closest that they came into was the association of deja vu with temporal lobe epilepsy. They pertain to this as a hypnagogic jerk that occurs prior to falling asleep.
Studies are still being pursued to explain this phenomenon and while it is still being discovered, we might as well stick to the fact that what we have seen may happen in a couple of hours.

