Hollywood makeup has come a long way. Remember when they painted Lou Ferrigno green on The Incredible Hulk ? His eyes and other mucous membranes were still pink. So I got to thinking, what if there is a harmless dye that can be used on those areas? I haven’t done much research on the subject but I found an article about dry eye that mentions special dyes that are used to diagnose eye problems. This at least confirms my hunch that there are people putting things in their eye besides saline and ointments, etc.
Almost Human does some excellent makeup effects.