Where is the DBL measurement taken on a frame?

• A. Across the bridge
• B. Across the temples
• C. Around the rims
• D. From nose pad to frame edge

Answer: (A)

DBL is the distance between the two lenses measured across the nose bridge. It is the horizontal width of the bridge portion of the frame, taken from the inner edge of one lens to the inner edge of the other where the frame sits on the nose. This is different from measurements that relate to the temples (temple length) or the overall rim size (around the rims), and it’s not a measurement from the nose pad to the frame edge. Knowing the DBL helps ensure the frame fits properly across the nose and aligns with the wearer's interpupillary position.