I used my iPhone as a webcam and my eyes are naturally relaxed to the point where the top of my iris is always hidden by eyelid and still worked like magic. You'd be fine with whatever you have, the calibration system is there for a reason.
Yeah! The calibration system is pretty great! I tried with two different pair of eyeglasses and it worked great. My only advice is to not play the game during dusk, since you'll need to re - calibrate the game by pausing it, and that breaks the pace a little.
Also there is an accessibility option that lets you control blinking with manual clicks. I assume it's on the Itch version, I own the Steam edition though.
