There are lots of people who want to change the world—people who wish to use their time and talent to “do good.” But there’s no clear roadmap for how. Many social entrepreneurs, myself included, trace our journey back to a lightbulb moment where a combination of right-place-right-time and active curiosity suddenly illuminated a path forward. That’s what happened to Dr. Jordan Kassalow, an optometrist and founder of VisionSpring, a nonprofit dedicated to delivering affordable glasses and vision care to the world’s poor. Now, he’s written a book called Dare to Matter: Your Path to Making a Difference Now to help others find their lightbulb moment and use their talents for good.

I’ve known Jordan for years, and see a lot of his journey as a social entrepreneur mirrored in my own. Both of us witnessed firsthand a social and market failure: in his case, 2.5 billion people unable to reach their full potential because they can’t access affordable eyeglasses; in mine, 2.5 billion people dependent on small family farms for their livelihoods, living in poverty because they are unable to reach larger markets. We each founded an organization to correct these failures—but the fact is that a single organization or entrepreneur can never create the bold change needed to address the scale of these problems. Even when the solution is as simple as a pair of glasses, transforming the lives of billions of people requires a systems change mindset. I spoke with Jordan recently about what makes a successful social entrepreneur, the importance of collaborating across sectors to advance large-scale change, and how anyone can make a difference in the lives of others.

WILLY FOOTE: Tell us about your journey as a social entrepreneur. What prompted you to found VisionSpring?

JORDAN KASSALOW: My path to founding VisionSpring began long before I knew that there was such a thing as a social entrepreneur. It actually started far more simply. I was on a post-graduation climbing and hiking trip with some friends in the Alaskan Brooks Range, and still a little uncertain as to what I wanted to do next, including whether I should go to optometry school.

Fortunately I had a moment on that trip of absolute clarity—not necessarily about whether to go to optometry school, but clarity about the kind of life I hoped to live. I was on a solo climb, and it was raining horizontally because of an intense wind. The scale and remoteness of my surroundings made me feel insignificant. And I hated that feeling that my life didn’t really matter. I knew then that I absolutely had to make my life and my time on this earth count—that I couldn’t just be here, but that I had to do something that mattered beyond caring for myself and the people I loved.

Everything in my life since then has unfolded from that core understanding—my true north. I carried that true north with me into a small village in the northwestern region of the Yucatán Peninsula, where, as a first-year optometry student on a volunteer medical mission, my very first patient ever—a seven-year-old boy named Raúl—helped me discover a problem hiding in plain sight. That problem was the significant unmet global need for glasses, and it ultimately led me to create VisionSpring. When Raúl sat down in the exam chair, his mother explained that he had been blind since birth. Upon further examination, however, we realized that Raúl was not blind, but actually needed an especially strong eyeglass prescription to see. Seeing that this boy’s entire future hinged on a simple pair of eyeglasses lit a fire in my belly that has never gone out. Ever since, my mission has been to make affordable, high quality eyewear and vision services available to what I would learn were 2.5 billion people the world over, for whom a pair of glasses is the only thing standing between them and an education or a job or even basic safety and security.

Click here to read the rest of Willy Foote’s article at Forbes