Dual PVS 14 Focusing/Eye issues


I have spent a significant amount of time under a single PVS 14 and have never encountered a focusing issue. I've always focused the ocular lens first to as clear of a picture possible, then focused the objective lens for the final corrections. When patrolling, I generally only ever messed with the objective lens in order to see something closer to my NVG and then would set it back to a distance setting. Recently, my broke as f reserve unit managed to get several PVS14 bridge mounts. I have attached an image of the bridge mount below. It is essentially a mutant dual j arm combo. Again, I can not emphasize how broke the Marine Corps Reserves is, and this is the cheap solution to prevent dudes from needing to buy new Norotos mounts for a dove tail adaptor.

I have probably less than 20 hours of time under dual PVS14's at this point, but am encountering a troubling issue. I focus my two devices separately, powering one on at a time to focus each as described above, then turn both on and match the gain and make any minor adjustments. While wearing the duals 14's, I definitely have increased depth perception, a better situational awareness, and generally feel more confident in what I can see. The issue arose when I conducted a few down device drills. Essentially we're practices lifting the NVG's, activating a white light, and engaging through an EO-Tech as if one or both of the PVS14s crapped the bed. When I lift my device and activate the white light on my rifle, my eyes feel like they are crossed a little bit and I get some vertigo. I noticed this feeling a little bit when I first started wearing them around the drill center and would take them off and I do not have any strange feelings or eye strain when wearing the duals 14's. It seems like the longer I wear them the more the "cross eyed" feeling persists when I go from Duals 14's back to the mark 1 eyeball.

With these mounts, we can not change the distance between PVS14 A and PVS14 B, and I am wondering if that could have something to do with it. Does anyone have any recommendations for anything I should change? Should I look into a different bridge mount to purchase myself, or just keep waiting for the PVS15's/PVS31's that have been promised for 6 years.


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...With these mounts, we can not change the distance between PVS14 A and PVS14 B, and I am wondering if that could have something to do with it...

Likely (people are weird, and I'm not looking at you doing it) you got it. You have very good binocular vision, and your eyes are adjusting themselves to the not very properly aligned nature of the "binocular" you have. Switch modes, and it takes a minute to get back to your eyes working the right way.

You should, I suspect, also be not 100% comfortable when you first put them on. Try something difficult, but safe (don't try running down stairs!) as /soon/ as you don the binoculars. I bet you have worse coordination, depth perception, etc as you do 10 minutes later once used to them.

You can also try an experiment more closely of your issue by grabbing a pair of plain old day binoculars when sitting around the team room waiting some day. Adjust the binoculars /not quite right/. Too wide or something, but good enough you can see through them. Now, look at something in the distance, for several minutes. Stop, look at other stuff, move around, etc. Same effect of vertigo and stuff? I bet.

IME, good bridges with adjustment are crazy expensive. I like them but not sure I'd want to bring my own in the field. Also... pretty different looking than the "dual J-Arm" style so if you are subject to Uniformity Police, may not be usable either. Oh, and... how are you issued this? Do you have check the NODs out then screw them to arms each time or does it come as a kit or... what?


I'll try out an initial task immediately after donning the the nods and getting them focused and see if you I'm getting it coming and going. If I ended up getting a good bridge mount, it would unfortunately not be the first time I was throwing a decent chunk of my own money to fix an issue...

The issuing process is the same as any other piece of serialized gear for the two PVS 14's, and we just had a dual arm signed out to each of us like a holster or magazines. So yes, each time we draw them they have to be re mounted to the dual J arm and then when the drill weekend is over, you take them off and turn the 14's into the armory and lock the dual arm in your cage.

Thankfully, the uniformity police are pretty lax at my company, one dude even brings in a pair of personal PVS31's. I might see if he'll let me try those out.


PVS 14 tubes don't have a tight collimation spec. Basically, each tube is making your eye look slightly off where it would be if you didnt have NVG's on, kind of like drunk goggles. You don't really notice this with mono use, but when you slap on 14 binos, it might make your eyes point in different directions.

You can improve collimation slightly by loosening the ocular lock ring and spinning the assembly. You'll want to mock up a ghetto collimation tool. A good way is placing a riflescope with adjustable parallax on the rear of an upper receiver. Put a red dot all the way forward on that upper receiver. On the scope, dial the parallax so that the red dot doesn't move around when you wiggle your head behind the scope. Dial your scope so that the red dot is on the cross hairs. Mount that PVS14 in the middle. You'll notice that the red dot probably is in a different spot now. Loosen up that lock ring, spin the ocular assembly around and you'll notice the red dot travel in a circle... pick a spot that's closest to the cross hair.

Adjusting your diopter affects the collimation and will move the red dot around that circular track, so it's gonna take a few back and forths with you getting it close on the ghetto collimation, and you checking the diopter adjustment with your naked eyeballs.

This shouldn't have any effect on the purge, but will miscalibrate your diopter adjustment. Miscalibrated dipoter isn't an issue that you'll ever actually notice, so I'd recommend it if you want to run dual 14's.

Ideally, you'd have dedicated binos, but sometimes you have to deal with what you've got.