I have a friend who wears very heavy makeup on a daily basis. She has dark, drawn on eyebrows, very large false lashes (think drag queen/vegas), heavy thick pink blush, and she lines her lips outside her natural lip line and then wears bright lipstick. The effect is very...theatrical. The first time I met her, my first thought was "kabuki theater." Her hair and clothing are always subdued by comparison.
I am a very visual, detail oriented person and I have trouble not staring at her makeup when I talk to her. Yesterday I was noticing that in direct light you could see the texture of her eyelash glue on her upper lids. I know it is rude to stare, but I'm not sure where the line is between making appropriate eye contact during conversation vs. staring at someone's unusual eye makeup. I don't want to be rude, but I can't not look at her face, and looking at her face means I will probably get distracted by something like how her blush creates such a geometrical line on her face or whatever.
On the other hand, I have worn heavy theatrical makeup (for night clubs or costume parties though, not at 11 AM) and I didn't mind if people looked at and noticed it. A comment like "I was just noticing your rhinestone eyelashes" to explain someone staring at me a bit oddly would have been fine. But since this friend wears this same makeup every day, if I took this approach, I would quickly run out of comments like "that's a pretty shade of lipstick" or whathaveyou to explain my staring.