So mfb believes that life energy on the astral plane has the same properties as light photon/waves? Meaning it can be refracted, distorted and focused.
Jason believes that the clarity of the astral plane rises above the perception of the physical plane as we know it. Distance no longer has an impact on range unless something is hidden behind an object. Meaning that life energy has no need to be refracted, distorted or focused, only concealed.
Since astral vision seems to eminate from the point of your consciousness, presumably in one's head and directed through their face, you can only assume that even if binoculars did change the perception of life energy, the lenses could not get close enough to the point of origin without being stuck directly into one's brain. Nor would bi-noculars do much good for a single consciousness' point of view. Astral vision doesn't have a direct anchor to a person's eyes as it seems they can percieve the astral plane even without use of their eyeballs.
My understanding of this situation is that holding up a pair of binoculars to a person's face would block out their view of the astral world, as holding your hands over your face might, and prove to be a distraction. (+2 to target numbers for Ranged attacks or spell casting, most likely.) The lenses being too small and too far away from the central point of consciousness to allow anyone to percieve anything through them. Only your physical eyes would benefit, still allowing you to see what it is you are looking for.