Honest, straightforward question: What does a change in uniform for one game have ANYTHING to do with Miles' policy for not allowing visors??? Miles' reasoning for NOT allowing them is because with injury--specifically head injury, detecting pupillary response is a baseline for concussions or worse. You need to be able to see his eyes quickly and not try to peer through a visor (especially tented ones...but even the "clear" ones can distort/reflect) to do so. Most players now wear it because it "looks cool" and are more interested in looking like a little badass, than simply worrying about playing like one. If ANY player at LSU under Miles' watch is going to wear a visor, it's going to HAVE to be a medical issue that REQUIRES them protection (i.e. Chavis Jackson wore one in the BCS title game I believe because he had an eye injury). Sure, you can claim that wearing them virtually protects the eyes from such things. You'd be correct. But the odds of a player getting poked in the eye don't exceed the risks you take if you can't properly treat a player for a head injury because you've wasted time trying to look through a visor or had to wait to cut it off--whereby you're moving the head unnecessarily and thus putting the player at further risk to cause more harm by moving him.
There was an issue in the 2007 LSU-Kentucky game regarding visors. I think one of their coaches challenged the refs and got one of our players to take off his visor. But, I think that was a tinted visor. Clear visors should be okay but there's really no point to wearing one. Your eyes are already pretty well protected and they fog up a lot. And pretty much what AtlantaBengal said.