For what it's worth, I had the MEPS eye exam, I believe all went according to Navy aviation requirements, and failed (DP). So, not to be deterred, I went to the family optometrist (as in the one my parents go to, I've never had any issues with vision), passed his depth test, and sent the results with my final selection package. They approved it, and I went through NAMI without issue. The only other person there who took their depth perception test at MEPS that I knew of also failed it (she was going Air Force, enlisted, and she said it dropped her out of their aircrew positions, IIRC). Long story short, don't sweat it; there are plenty of people who pass the MEPS test only to get the NAMI whammy (probably in many cases because it's improperly administered), and plenty who are the other way around, like me. I found a webpage back when I was working on my application that has all the requirements, don't remember where, but you could probably find it with a Google search. Just make sure you're getting the right things if you're required to get it done independently.
By the way, there were three people, two pilot, one NFO, between the two classes I was in that got the NAMI whammy. One was back issues, one had something to do with a psych evaluation in the guy's record, and the NFO was because of a concussion in his record. So none of them were vision related, and I don't remember anyone losing their aviation slot because of vision issues while I was in OCS. Not that it doesn't happen, it does, but it's not necessarily the most common reason, and yes, MEPS probably carried some culpability with the cases I mentioned. As for the vision tests, just remember, if the ring doesn't jump out at you, shift your gaze a little, try to move your focus around, don't stare, and DON'T PANIC.