My $0.02.
I realize this isn't what you asked and you may already know all this, but in my opinion (and in case you haven't) divers should have some degree of comfort diving without a mask with their eyes open. If your mask gets knocked off, even seeing a blur may help you get it back, or read your gauge and surface safely. Some contacts stay in the eyes better than others underwater (size), and you may be less worried about loosing one if you dive with cheap disposables.
Just something to keep in mind.