When the cute yellow school bus parked outside his shop on 18th Street on two consecutive Saturdays in 2012, Cliff Balter was not amused.

Balter owns Innervision Eyewear, which has been at 131 S. 18th St. since 2010. The bus was a mobile showroom for Warby Parker, which was selling eyeglasses online. Can you say, "In yo' face"?

Warby Parker - which has since grown huge - was launched in 2010 by four students at Penn's Wharton School. They pioneered the online concept of selling affordable eyewear to customers in the comfort of their homes.

The concept was so new that Warby Parker sent the school bus - a mobile showroom - to 15 cities around the country to create a physical presence for potential customers. The company called it a "class trip."

Balter was particularly unamused when he saw some of his customers checking out the eyewear on the bus, although he admits his business didn't suffer at the time.

That was then: on-the-street retailer vs. online.

That equation will change a little Saturday morning when Warby Parker opens a brick-and-mortar retail store at 1523 Walnut St., formerly Georges Perrier's beloved Le Bec-Fin (RIP).

Balter, 41, is ready to "welcome" Warby Parker to the 'hood.

But first, a little backstory.

Balter's first encounter with the eyewear game came when he was 12 and his single mom, Joyce, took him to get glasses at Glasses Galore in the Northeast, where they lived.

While Balter got eyeglasses, Joyce caught the eye of the store owner, Mark Miller. They started dating and got married within a year, creating Balter's pathway to the eyewear business.

He and his wife, Emily, opened Innervision, a high-end eyewear store in Manayunk, in 2002. They relocated a couple of times and were on 18th Street when the unwelcome school bus arrived in 2012.

"On the one hand, it was smart," says Balter. "On the other hand, it was insulting."

Warby Parker supposedly is competing with Luxottica, the global giant that almost owns the eyeglass trade. Says Balter: "That's the story they've been telling to the public, but they parked in front of independent little guys like me."

By email, Warby Parker co-CEO Neil Blumenthal told me, "All four of us lived in and around Rittenhouse Square - that's why we decided to bring the class trip bus to the area."

Although the Warby Parker website doesn't name Luxottica, it says that "the eyewear industry is dominated by a single company that has been able to keep prices artificially high while reaping huge profits from consumers who have no other options."

Warby Parker presented itself as the option. It has frames with single-vision lenses starting at a low $95.

Customers can shop for frames online and get five pairs sent to their home to try on. If they don't fit right, customers get adjustments at their local eyeglass store.

The free adjustment is a common practice, says Balter, who is irritated that Warby Parker shifts that cost to the little guy.

"They are portraying themselves as David," says Balter. "That's why it's so insulting. I'm David. American Express was paying for their bus."

That's true. The Penn students' business plan attracted venture capital, including a big investment from American Express.

Rather than just curse the darkness, Balter says, he was inspired by the incursion by Warby Parker to start a low-cost eyeglass line called Philly EyeWorks to add to the 3,500 frames he carried in his boutique. Most of those frames were in the $300 to 700 range, plus lenses. The Philly EyeWorks frames start at $150, with lenses, and are hand-finished in his Philadelphia shop from parts made in China.

The names of his frames are Phillycentric: Brotherly Love, Yo Adrienne, Fo Fo Fo (think Moses Malone), Love Train, West Mount Airy, and my favorite, New York Complex. He has 21 styles and hundreds of color combinations, and can do custom colors.

So that brings us to the present.

From noon to 3 Saturday, Balter will have a handful of people in front of the new Warby Parker store - he has the city permits - handing out $50 coupons for glasses at Philly EyeWorks, bringing down his usual $150 price to match Warby Parker's $95.

"We are not there to picket them. We are there to promote our brand. We got the idea from them," says Balter, with a self-satisfied smile.

Payback is a bitch.

You can't be there Saturday? Balter is offering the $50 coupon at his shop through February.

No school bus, just his way of welcoming Warby Parker to his neighborhood.

215-854-5977 @StuBykofsky

Blog: ph.ly/Byko

Columns: ph.ly/StuBykofsky