Fortune has learned that Warby Parker, the New York-based sunglass and eyeglass retailer with a decisively 21st century tech-driven “try-before-you-buy” model for its flashy frames, will begin accepting UnitedHealthcare vision insurance in 2018—a first for Warby Parker, which hasn’t accepted insurance up until this point. The partnership will affect about 20 million people with UnitedHealthcare employer-sponsored and individual insurance plans that include vision coverage.

Warby Parker frames typically cost about $90 and upward depending on the model and prescription. So just how much could you save under the new deal? “It depends on the specific co-pay a customer has under his or her plan,” Warby Parker co-founder and co-CEO Dave Gilboa told Fortune in an interview. “But based on the average UnitedHealthcare co-pay, a pair of Warby Parker glasses would be about $30 out-of-pocket with insurance.”

“We look forward to working with UnitedHealthcare, nationwide, to enable millions of Americans to purchase their glasses at a fraction of the price they might pay through traditional channels,” Gilboa added in a written statement.

Warby Parker has a reputation as a quintessential millennial startup. But the company’s founders have always taken vision care needs very seriously, regularly pointing out that about a billion people around the world don’t have access to the kind of eyewear they need, which takes a toll on their productivity and livelihoods. “We think it’s really important to expand access,” Gilboa said. That’s one reason the firm has a broad nonprofit initiative to provide glasses to the less fortunate.

Tom Wiffler, CEO of UnitedHealthcare Specialty Benefits, said the company is “grateful Warby Parker selected [us] to be its first in-network vision plan” in a statement. Gilboa says that Warby Parker may take insurance from more plan providers down the line.

Warby Parker is expected to bring in more than $250 million in 2017 revenues.

This post has been updated with a more accurate revenue figure.