Proper vision is essential for work and education. Put simply, if you can't see, you can't work or learn. In this way, clear vision is an economic development issue—across the developing world, there are millions of middle-aged people who can't work and millions of children who can't succeed in school because of vision problems that a $4 pair of eyeglasses could correct. We at VisionSpring see this as entirely unacceptable and aim to ensure affordable access to eyewear, everywhere.

In 2003, VisionSpring sold 800 pairs of eyeglasses. In 2013, we sold 481,000 pairs in 26 countries across Central and South America, sub-Saharan Africa, and South and Southeast Asia. Although our sales volume has increased dramatically, when measured against the 700 million people who need but don't own eyeglasses, our achievements haven't made a dent. What will it take for us to achieve transformative scale—a 10-fold, 100-fold, or even a 1,000-fold increase in sales—and inspire others to do the same? We are pursuing three complementary approaches:

1. Scale effective business models. One of our central tenets is not to scale losses. VisionSpring works to create viable business models that are fully cost-covered. We scale up a model only when it is profitable and easily replicable. We start small, creating a blueprint for the particular model, and then test, refine, and prove its profitability. Only when a model clears these hurdles do we initiate a more aggressive replication effort.

We are currently on this path with two distinct models. The first is our partnership model with BRAC in Bangladesh, which takes advantage of its vast network as a distribution platform; we have spent five years proving that BRAC's local community health workers can learn to responsibly and efficiently sell reading glasses. We tested the concept with 50 women, then 500, then 5,000. Last year, we signed a memorandum of understanding with BRAC to train an additional 25,000 workers, and over the next five years, we aim to sell 1.7 million eyeglasses through this channel.

The second is in El Salvador, where we are testing a "hub and spoke " model. Here, we build a central optical store that employs an optometrist, and then we recruit and train "vision entrepreneurs" who fan out into the surrounding communities to sell reading glasses and refer patients who need more advanced care back to the central store. We started with one store, made it work, and now have five that are profitable. Our board just approved expansion into Honduras, Guatemala, and Nicaragua, where we will build an additional 25 optical stores over the next three years. Once those are profitable, we hope to scale up to 300 stores. As with our BRAC model, this build-out has the potential to serve millions.

2. Continue to innovate and improve. We are proud of the models we've created thus far and will expand these as far as possible. But we are not so naïve as to believe that these models, by themselves, will get the job done. We and others must continue to innovate to enable greater access to low-cost reading glasses. We must find new collaborators, use other distribution platforms, and continue to drive down product costs while maintaining the quality and attractiveness that create customer demand. This will lead to the creation of additional business models that nonprofit and for-profit players could expand to reach tens or hundreds of millions of people.

3. Build a movement. The final ingredient required for success is to dramatically increase the attention, energy, and funding that the global development community devotes to this issue. To achieve this, we need the world to understand the fundamental connection between proper vision and economic development—something that will require increasingly deep and cooperative partnerships among governments, the private sector, and civil society. To this end, we are launching Eyeglasses for Everyone, a movement built on three pillars:

• See to Learn: Given the proven impact of eyeglasses on education, we will work to implement policies and programs to ensure that every school child who needs eyeglasses gets them.
• See to Work: Given the proven impact of eyeglasses on productivity—a 35 percent increase—we will work to implement policies and programs to ensure that every adult who needs eyeglasses for work gets them.
• See for Safety: Given that roadway accidents are a leading cause of death in developing nations—59 percent of traffic accidents have a visual component—we will work to implement policies and programs to ensure that drivers who need eyeglasses get and use them.

For the social enterprise movement to live up to its promise, we need more examples of transformative scale. For us, this has required us to pursue multiple pathways simultaneously: using existing platforms for distribution; creating profitable models that are easily replicable; attracting other organizations (particularly in the private sector) to sell to underserved markets; and building multi-sector partnerships to adopt the vision issue, place it on the global development agenda, and thereby help initiate large-scale efforts to solve the problem.

VisionSpring's next big push is focused on this global development agenda. We aim to insert and elevate the issue of vision to its proper place within the broader movements for education, economic productivity, and road safety—thus helping to truly transform society.

VisionSpring CEO Kevin Hassey has an extensive background in the optical industry, including serving as president of LCA Vision—the nation's largest Lasik surgery company—and vice president of marketing at LensCrafters.

Jordan Kassalow is founder and cochairman of VisionSpring. He also founded Scojo New York, maker of designer reading glasses, and the Global Health Policy Program at the Council on Foreign Relations. Kassalow is a Skoll and Ashoka fellow, one of the Schwab Foundation's 2012 Social Entrepreneurs, and a Forbes magazine Impact 30 designee.