Some folks on here have gone thru AN/PVS-5 full face goggles, AN/PVS-5 cut-away goggles (I remember at least 3 mounting systems for these), AN/PVS-5 COBB mount = each version got a little lighter and more user friendly.
The original ANVIS were lighter yet and much better visual acuity. Some folks were using Litton 909s about the time the Army decided on their original ANVIS purchase. From the original ANVIS 6 to todays standard has lost very little weight, but the acuity and filtering has been greatly improved. We have also seen trys at different color portrayed to the eye, brown, yellow, red. ect.... Now you can add weight back to the NVG with clip-on HUD, clip-on compass ect...
Current NVG are not quite 1/2 the weight of the original AN/PVS-5, but they are not far off. Add to the original AN/PVS-5 a counterweight of nearly a pound and a half that you have to use to keep your helmet sitting steady. I have never had to use a counterweight on the ANVIS, so they are easily two to 2.5 pounds lighter than a PVS-5 set-up.