Field Small Backpack

If you have a pair you love wearing, look on the inside of either temple – most frames have three numbers printed there (something like 50–20–140).

Compare them to ours: 

• Lens width shapes how wide the frame looks on your face. Within 2–3 mm of yours will feel familiar.
• Bridge is the gap between the lenses, and the number that matters most for comfort. Too narrow pinches; too wide slides.
• Temple is the length of the arm. A few millimetres either way is rarely noticeable.

If the numbers aren't printed on your glasses

Lay your pair flat and measure across the front, outer edge to outer edge. Ours measures roughly 112 mm across. Within a few millimetres will feel familiar. 

If you don't wear glasses

Hold a standard credit card horizontally just below your eyes, edge to edge with your temples. A credit card is 85mm wide. If our frame (112 mm across) feels about a card-and-a-half wide, you're in range. Our Small–Medium fit suits faces around 125–140mm wide, measured cheekbone to cheekbone.

A note on adjustability

Every pair is built with precision hinges and an integrated metal wire core running through each temple, so even if the fit isn't perfect out of the box, the arms can be gently shaped for a fit that's truly yours.

Yes, the temples have a metal wire core, which allows them to be shaped for a custom fit.

The nose bridges are integrated acetate without adjustable nose pads. The wire-core temples can be reshaped for a custom fit.

Acetate frames of this style use fixed bridges rather than adjustable nose pads.

Lenses are UV400, offering 100% UV protection.

Our CAT.2 and CAT.3 ZEISS CR39 polymer lenses are not polarized to best support all uses including reading screens and seeing in dim conditions.

Mira sunglasses use Zeiss CR39 polymer lenses. CR39 is described as the highest quality polymer-based lens in terms of strength and optical clarity. Zeiss has led the science of optics since 1846. Zeiss CR39 lenses include scratch-resistant treatment as standard.

Cellulose acetate is plant-based and generally well-tolerated by sensitive skin.

We use standard 3-barrel or 5-barrel hinges, depending on the model – offering increased durability, stability, and longevity by distributing stress across the interlocking metal parts.