Count Doodoo
The Minimalist
Maybe Anakin will get angry and then his eyes will turn yellow and then they'll use Lou Ferrigno as a stand-in. Juuust Kidding! 😄
It looks like you can see the separatist's conference room in the background (with nobody sitting at the table -- maybe they're all on the floor dead) so perhaps that's how he looks at Obi-Wan and/or Padme when they find him on Mustafar. Maybe the yellow eye thing will just be used to make it obvious to the audience that Obi-Wan and Padme know that Anakin has turned to the dark side. Maybe we'll understand it better at that point after having seen Palpatine's transformation and what caused it.
It's still possible that the shot with Anakin with the yellow eyes was just exclusively for the trailer, or is part of a dream/vision sequence, but I still don't think either of those possibilities are very probable.
I don't think that Anakin's eyes just turn yellow because he's enraged either, because he looks like pretty enraged when he's choking Obi-Wan in the trailer and his eyes aren't yellow.
Oh, btw, I saw Darth-Maul-type contact lenses for sale at an optometrist's office one time. They'd go good with a ROTS Anakin costume, wouldn't they?