In both The Desolation of Smaug and Battle of the Five Armies, there are scenes where good characters face Sauron and there is an almost-psychedelic effect:
Both Gandalf (in 2nd film) and Galadriel (in 3rd film) face Sauron in his "eye form" in Dol Guldur. At one stage in each battle, the flaming eye of Sauron is shown on screen, and the pupil shape is not a slit, but the shape of a standing figure, which repeatedly zooms forward then flashes back to zoom forward again.
This and similar effects continue, without dialog, for a few seconds, and it seems quite likely, to the point of being laboured, that something otherwise unseen/unspoken is happening between the characters.
It struck me when I saw this that the effect is not really in keeping with other instances of supernatural forces shown in the film, even in the same scene. The rest of the effects in the film are more fluid and modern CGI which most of us are familiar with. Whilst this particular effect seems like a throwback to 1970's fantasy and sci-fi (even though of course it is rendered beautifully)
So I was wondering:
Is the type of effect here chosen to visualise something specific from Tolkien's writings?
Is the effect a homage to some other fantasy/sci-fi film?
I am hoping here that the truth is to be found either in some interview with the VFX team, or via some Tolkien writing other than the Hobbit or Lord of the Rings. Direct searches for this specific information don't get me anything other than general descriptions of effects in the movie.