Fit
Reading the numbers on a frame
Lens width, bridge, and temple length: the three numbers inside the arm.
Three numbers, in millimetres
Most frames print three numbers inside a temple, such as 52□20 145. The first is the width of one lens, the second the bridge between the lenses, and the third the length of the temple from hinge to tip.
Shops often list the same numbers on the product page, sometimes with the lens height and the total frame width. The total width is the one that tells you most about how a frame sits on your face.
Using a pair you own
The easiest guide is a pair that already fits. Read its numbers, then compare: a lens a few millimetres wider or narrower changes the look more than the fit, while a bridge that is too narrow pushes a frame up off the nose.
Labels measure in slightly different ways, so treat the numbers as a comparison, not a promise, and read the shop’s returns terms before you buy.
In the shops
Square and rectangular frames
Nothing in the shops matches today.