actually I did mean the lenses, I've done it on a couple of pairs with no failures, the trick is to not have them too close together, not too big (2mm max), & pilot the holes first with a SHARP 1mm bit, in order to put no pressure on the lenses.
Obviously the holes need to be at the very top of the lenses, not anywhere near the eye area itself.
& obviously I'm not advocating anybody else do this, my choice,my risk, but I had tested this method on similar units that had suffered scratches in use, & then shot the shit out if them point blank with a slightly hot gun, with no failures.