Our ped did a basic vision test, at age 4 or 5 for my son, he didn't do well the first time, and a year later they did it again and sent us on to a optometirst. andhe did end up wiht glasses.
A couple of ideas, we have a vision and blindness resource center in our area, that actually go around to some preschools and do basic testing, i bet if you called them you could bring her in and have it checked that way.
you might also beable to find directions online or something to print out and hold a certain distance away from her and check that way, not super accurate but could get you by for a while.
I don't handle our insurance, if this is something you can put off for just one year, i think i would wait to enroll her, if this is something that you either do now or miss out on for three years, i would enroll her. especially if mom and dad need corrective lenses. Just what i am seeing is that kids are being identified in kindg, maybe 2 of the 20 kids, then in first grade, 5 of 20 and by third grade more like half. this isn't super accurate but the chances of having perfect vision by the end of elementary school if both parents have glasses seems slim to me.
Call an eye dr and ask.