What is the silver disc shaped eye piece thing a doctor wears called?

[Mano]

I need to know what the silver disc shaped eye piece thing that a doctor wears on a headband is called, and I can't seem to find it on the internet. I figured one of you guys would know. Any help appreciated. Thanks.

[bisonbison]

Parabolic mirror.

[Skipbidder]

We always call it the silver disc-shaped eye-piece thingee.

I actually don't remember ever seeing anyone wear one. (Except maybe dentists?) However, I can now think of multiple situations where it would come in pretty damn handy.

[Bluffoon]

spec·u·lum (spky-lm) KEY

NOUN:
pl. spec·u·la (-l) KEY or spec·u·lums
A mirror or polished metal plate used as a reflector in optical instruments.
An instrument for dilating the opening of a body cavity for medical examination.