What's gonna happen if I don't do good on the vision test at the DMV for the permit?
You will not pass nor receive a license. Next, you will be instructed to have your eyes checked for possible need of glasses. Then, you may return to retake the test, and pass with flying colors.
You'll have to wear your glasses when you drive. If you don't have glasses, you'll need to get them.
And your license will indicate that you must have glasses (or other vision aid)
You won't be able to get your license! Get your eyes checked if your worried