There is an interesting thread running on another forum about LED aircraft lights not being visible to pilots flying with night vision goggles. Apparently there are quite a few helicopters flying around at night with the whole crew using NVGs.
So it is apparently safe for these military/police pilots to fly at night with devices that give a very restricted monochrome view while it is seemingly unsafe for me to fly at night because of my CVD, despite my better than average 6/4 distance vision. Doh!