Read the three core measurements
A notation such as 54□20—145 usually means a 54 mm lens width, a 20 mm bridge, and a 145 mm temple. Some shield and rimless designs use different conventions, so confirm the supplier’s measurement method when the notation is incomplete.
Treat shape and width together
Two frames with the same lens width can fit differently because of bridge construction, lens depth, end-piece position, and overall frame width. Compare the full front view and side view alongside the written measurements.
Build an assortment across proportions
A retail buy is more useful when it covers compact, standard, and wider fits instead of repeating one proportion. Track total frame width where available, then group the assortment by silhouette and likely fit rather than relying on gender labels alone.
Publish measurements consistently
Use the same field order on every product page and state when a measurement still needs confirmation. Consistent product data reduces pre-sale questions and gives search engines and AI answer systems clearer facts to retrieve.
Quick answers
What does 54□20—145 mean?
It normally indicates 54 mm lens width, 20 mm bridge width, and 145 mm temple length.
Is lens width the same as total frame width?
No. Lens width measures one lens. Total frame width also includes the bridge, rims, hinges, and end pieces.
Can two 54 mm frames fit differently?
Yes. Bridge design, lens depth, curvature, end-piece position, and overall width can make the fit noticeably different.