The frame width refers to the distance between the ends of your frame, including the hinges. To achieve the best result, both in terms of look and fit, the frame width and the width of your face should correspond fairly. If the frame is too wide, you can risk the eyewear looking too oversized to your face, and there might be a greater risk for the eyewear to slide down and your view being distorted. A too-narrow frame can on the other seem too small for your face and pressure against your temples, potentially leading to headaches.