Ok, so I'm not sure exactly how this case would effect stat numbers with regards to perk requirements.... so here goes:

Lets assume I've gone through the list of perks and wanted to use 'Light Step' and 'Sniper' which both require a minimum 6 PE. BUT, while character creation, the trait 'Four Eyes' was selected, which if the wikia is correct, is a +/- 1 to PE whether I'm wearing glasses or not.

SO, the big question... If I create my character with the minimum 6 PE requirement for the perks I want, will the selected trait lowering my PE make my perks unavailable? If so, would they become available if I wore glasses? And finally, if yes and I remove the glasses, what happens?

I think my brain is melting thinking about this.

If it's the same as Fallout 3 then the perk requirements will go by your actual stats, which in this case would be PER 6. Even if you're not wearing glasses, and it drops to 5, you'll still be able to take perks that require 6. That is, if it's the same as Fallout 3. Which I suspect it will be

Thanks. Hopefully that's correct! It's worth some testing!

Um sorry to say but the way that perk is set up almost certainly it drops your perc 1 point but then gives you 3 when wearing glasses. Thus you would need 8 perc to wind up with that perc available.

I hope it goes by your actual stats, not any effects you have.