Starting with just $150,000 in venture capital and a $50,000 line of credit, Warby Parker has emerged as a fashion giant, selling over a million pairs of designer eyeglasses. More than that, it’s made the world a better place, donating an equal number of eyeglasses to needy people in the developing world while maintaining a net zero carbon footprint — and earning a substantial profit for its investors. I sat down with co-founders Neil Blumenthal and David Gilboa in their New York headquarters and talked to them about start-ups, risk-taking, collaboration, creativity, and entrepreneurialism.