Vibrating Sensation in Middle of forehead during meditation? Recently during my meditation sessions I have been getting a vibrating sensation between the eyebrows sometimes it can be quite intense. 

I have looked online and from what I can find it suggests this sensation refers to the "third eye". Just wondering if this is mentioned in any buddhists texts and is sensation normal?
Yes the sensation is a normal condition.

It is just muscle/nerve spasms. They may be happening throughout the day but go largely unnoticed. They are also at level of neuron firings so you typically will not be able to see them physically. During meditation you are probably more aware of the tiny changes in your body. One thing I notice during meditation is how loud my stomach has been this last week. The more you become aware of them the more intense they will probably appear to manifest. Unless it is a medical condition such as a hemifacial spasm they will typically go away on their own.