This might more properly belong in the Biology section, but I figure that it might involve other factors. There's something that I've been observing for decades, but never actually noticed until last week when watching an Extreme Close-Up shot in a movie. Can anyone explain why an actor's pupils don't contract under the intensity of shooting lights? I'm seriously photophobic, but have been in 4 movies which involved hours and hours of being lighted. Those suckers are bright, but they didn't bother me. Seemingly, no actor is discomforted by them, other than sometimes the heat. Is it simply a matter of spectrum range, or polarization, or what? An acquaintance of mine is a movie lighting grip, but I haven't seen him in a couple of years and doubt that he would know the answer to this anyway.