Seems to me you'd have to be a big-name actor to be able to call the shots and keep your job. Maybe Michael Caine was able to persuade the director that he looked better in glasses, or that it would add some realism, uniqueness, whatever. Even then, he must have had a very open-minded director. Most directors freely indulge stereotypes: people who wear glasses are nerdy intellectuals, fat people can't fall in love (in fact, fat people can't do much of anything except provide comic relief), the leading man must be about 3 to 5 inches taller than the leading lady, and so on.

I used to be an amateur stage actor. I've actually had directors, at auditions, order actors to line up so they could compare heights!

I have always worn glasses, never contacts. Directors nearly always wanted me to perform without them. Of course, if it's a period piece, and your eyeglass frames aren't appropriate for the period, they have to go. Amateur theatres don't have the budget to buy you a new pair, but this should be no problem for most Hollywood movies.

Fortunately, after weeks of rehearsing, I could easily walk through my role without running into walls. I figure it was actually an advantage NOT to be able to recognize people in the audience. That could be terribly distracting. The toughest part was getting into position backstage before the curtain call. Tough because (1) this has to be done quickly in the dark and (2) the curtain call usually isn't rehearsed or even planned until a day or two before opening night. I often had to have another actor lead me by the hand.

I saw Drew Carey on a talk show recently. He has had LASIK surgery and no longer needs glasses. However, he said he has discovered that glasses have become a sort of trademark for him, so he will probably continue to wear them, at least in his sitcom.