Frame sizing
A frame size is typically noted as: lens width – bridge width – temple width. For example: 51mm – 21mm – 145mm.
The key is finding a size that corresponds to the overall width of your face, while being mindful of the distribution of the physical size of your eyes (lens width) versus the space between them (bridge width).
As a rule, I think sizing should be treated on a case-by-case basis, as it depends largely on your proportions and the style being selected. But as a general guideline, here are some starting points for total width (lens width x2 + bridge width):
Small/Narrow Face: 125mm – 129mm
Medium Face: 130mm – 134mm
Large Face: 135mm – 139mm
Wide Face: 140mm – 145mm
The keys to proper eyewear fit
1. The width of the frame should match the width of your face. This means, when looking at you straight on, the glasses should not hang off the side of your face (this would mean the frame is too wide) and we should not be able to see the sides of the temples (this would mean the frame is too narrow).
2. We should be able to see your eyebrows above the frames. At least half of them, preferably a little more than half.
3. Each eyeball should be directly in the center of the lens, from left to right. The distance between the corner of the eye and the edge of lens should be the same on both sides of the eye.
4. Your eye should fill the top half of the lens. The bottom of the eye should roughly touch the vertical midpoint of the lens.
5. The temples should be adjusted to fit around your ears. If you have a problem with glasses sliding down your nose, you need to have the temples bent to keep them in place.
6. The overall frame should be located roughly in the middle of your face. It should provide a nice balance between the top of the face and the bottom of the face. In each of the examples below, notice there is roughly equal distance between the top of the frame and the top of the head, and the bottom of the from and the bottom of the chin.
