Ooh, do you remember where you read that film note? It'd be interesting to know, the eye bit was just what I observed from watching the film (that, and Deckard was the only "human" who's eyes I saw do that). I'm not sure that you can do that trick by mistake, since human eyes don't turn animal-like even with stage lights...

"To me, the theme of the story was about what makes a human a human - emotions, empathy, memories - and what you call something that isn't biologically human, but is capable of these things..."

Isn't that why Deckard as a replicant gives the story a punch? He proves that replicants are no different from the humans (shorter life spans aside), and that humans have only clung to that dividing line because they were afraid of being surpassed by their own creations.