The “insurance” company presents a higher barrier, since it is basically the government handing a discount to people for buying via employer subsidized vision “insurance”. The discount is that this benefit can be paid with pre tax dollars, so it obfuscates the real prices when people with vision insurance shop for eyewear.

I put “insurance” in quotes because the annual benefit maximums, like dental “insurance”, are so low that the premiums are simply prepaying for routine exams/eyeglasses. In effect, employer subsidized dental/vision insurance is just an advantage for large employers who can afford to administer those benefits and the employees who are lucky enough to work at those kinds of employers get to pay for routine dental/vision with pre tax dollars.