Before Warby Parker, the eyewear retailer worth more than $1 billion, was launched, none of its four founders had ever started a company before. So Dave Gilboa, Warby Parker’s co-founder and co-CEO, made a point of asking for guidance. “We spent a ton of time getting advice and mentorship from people who had either started a business before, or who had expertise in a specific area—like optometry, fashion, design, or e-commerce,” Gilboa says.

One of those mentors was Jordan Kassalow, an optometrist in New York and the founder of VisionSpring, a socially minded company that aims to make glasses more accessible to communities with limited access to eye care. For the The Atlantic’s series “On The Shoulders of Giants,” I spoke to Gilboa about the kind of guidance that’s required to start a company from scratch, how he got the idea for the company, and which frame designs never made it to production. The conversation that follows has been edited for length and clarity.

B.R.J. O’Donnell: You’ve said in other interviews that you weren’t just trying to start a business—you were trying to start a business that would change an industry. Did that make it difficult to find people who could offer you guidance?

Dave Gilboa: Most people, when we told them our idea, their reactions were to tell us why it wouldn’t work. I think that’s just a natural human tendency, that when something is new, and it’s different to what you are familiar with, most people tend to react negatively to that. I think that a good mentor is someone who can tell you when you are being delusional, but can also be inspirational and provide encouragement—even if it’s something that they might have questions about, and even if they don’t have direct experience in what you are doing.

O’Donnell: What did Jordan Kassalow, of VisionSpring, say that was different from what you’d heard from other people?

Gilboa: He is an optometrist who runs a very successful practice; he has seen the traditional model of selling glasses. That model has been successful for him and a lot of colleagues. Most people that we talked to in those positions really shot down everything that we were doing. They’d tell us, “Well, if this a good idea, someone would have done it by now.” Instead, Jordan took a different approach. He asked us tough questions so that he could provide good guidance and offer specific expertise. But he also saw that we were super excited about our idea, and he encouraged us to pursue it. I think that was more helpful than anything else, providing that encouragement. I think that’s what a good mentor should do.

O’Donnell: How did you meet Jordan?

Dave Gilboa, left, and Neil Blumenthal, the co-founders of Warby Parker (Derris)

Gilboa: My co-founder, Neil Blumenthal, was the second employee of VisionSpring, and had worked with Jordan for several years before coming back to business school, which is where we met. While he was working at VisionSpring, Neil had actually designed and helped produce glasses that were made to be affordable for people living on less than $4 a day. As a result, we had a very strong relationship with Jordan, and we were able to spend a lot of time with him working to understand every aspect of the optical industry. And he became one of our earliest investors.

O’Donnell: What’s the most interesting thing that you learned from Jordan?

Gilboa: That there are hundreds of millions of people around the globe that need corrective lenses and don’t have access to them, and that getting someone a pair of glasses is one of the most effective poverty-alleviation tools in the world. The University of Michigan did a study [co-authored by Kassalow] that found getting someone a pair of glasses increases their earning potential. It’s such a simple tool, and it’s a technology that has been around for as long as 800 years. It’s crazy to think that such a huge percentage of the world’s population doesn’t have access to it.

O’Donnell: Can you tell me about the process of creating the first collection of Warby Parker frames?

Gilboa: We initially started by thinking, “Okay, what are the glasses that we would want to wear?” And we started developing some prototypes. We ended up with a collection of 27 initial styles, and then we got feedback from Jordan.

O’Donnell: What was his take on those early ideas?

Gilboa: We were interested in having a couple of shapes that were a bit oversized. Jordan said, “These glasses look cool, but the optical properties are not going to be great.” He explained to us that for prescriptions over -2.00 or -3.00, which are pretty common, the lenses would end up being so thick inside those frames that it would look kind of ridiculous, and that no one would want to wear these shapes. So we struck those styles from the initial collection. He helped us translate our vision into something that was wearable—that didn’t just look cool, but were also functional.

O’Donnell: I’ve read that the idea for Warby Parker was sparked when you lost a pair of expensive glasses while backpacking. What about that experience made you think about a business opportunity?

Gilboa: They were Prada glasses, simple metal frames, and they fit my face well. I had gone to my optometrist, been given my prescription, and then looked at the frames out in the front in their office, and I just chose one—I had never stopped to think about why glasses were so expensive. When I lost those, I needed a new pair, and it was at a time when I also needed a new phone. The iPhone 3G had just come out, so I went to the Apple store, and I paid $200 for one. It did all these magical things that people couldn’t have even contemplated a few years earlier. That made me start thinking about why I was being asked to pay $700 for a new pair of glasses. Something just didn’t compute.