I've known that the third eye is actually the place for 'agna' chakra in the body, and that the third eye is actually a metaphor for reaching that high level of conciousness where you start seeing things the way they are. And lord shiva, who is 'trilochana' clearly shows this by his form, and his actions of, for instance, destroying 'kama'(lust) with his third eye.
This would actually be a metaphoric action, which would mean, if you have attained highest knowledge, then you can destroy lust, which is persistent to human nature.
But my biggest confusion is, if the third eye is the symbol of knowledge and highest conciousness, why does the third eye of lord shiva open up with rage? Knowledge as any one would say would be obtained with time, patience and effort, in the contrary, why would our energy reach the 'agna' with rage?
EDIT: ARE THERE ANY VERSES TO SUPPORT YOUR REMARKS?