ViFlex glasses are made from three simple, modular components that allow users to adjust the frame size and to swap in different lenses until they determine their desired prescription strength. This approach provides flexibility in terms of both frame fit and prescription needs, without requiring optometrists and technicians downstream in the distribution process. Our approach reduces costs and delivers increased value to end-users, in addition to complementing scalable base-of-the-pyramid distribution models used by many NGOs.