So I know vampire eyes were changed in Dawnguard, how does this affect Argonian eyes? I've seen a lot of people complaining about them, is it that bad?

I'm not sure what the problem is, I think your eyes don't change.

So if I choose to 'side with Harkon' at the start of Dawnguard do I have to get the big glowing orange eyes or do I keep my old Vamp eyes? I just think those eyes would look really dumb on a Argonian.

the eyes dont change for either beast races. its a subject of controversy, some people want them; and some dont

( This is from my friends game, not my own)

If your already a Vampire and you choose to side with Harkon his eyes went from being black to white, and his skin went back to its normal color after already being pale, Im not sure if this is a glitch that happens all the time when trying to become a vampire lord from a normal vampire....im also pretty sure this fixed after a few reloads ( not to sure on that though ).