In my personal experience what I wear doesn't make any difference, some days I wear glasses others I wear contact, doesn't matter if I have my hair down or tied up, nor makes any difference what I wear. However, I've seen my birds frightened by my mum wearing her new coat and when my daughter wore a hat. Strange thing is they aren't bothered by my grandsons appearance either, his first time wearing a hat out didn't phase them at all, nor when he wore his new coat.
I have a blanket I put on my lap to help keep warm while sitting out with my birds, ordinarily they aren't bothered by it and those that get on laps will still get on but one night my daughter came out with it drapped over her shoulders and scared the birds half to death but this evening she sat with it on her Lap and they were fine jumping up on her lap. Strange but wonderful birds