When we ask customers to first measure their eyeglass temple tip diameter and temple bend diameter before they buy Keepons, an astute observer will notice that our fitting process actually involves asking you to measure your temple tip width and temple bend width.
That's because while it's easy to measure the diameter of a hole, measuring the diameter of a portion of your eyeglass temple is impractical. To truly measure the diameter, you'd need to cut out a cross-section of the temple and measure the diameter of the circular area you've created. One pair of expensive glasses ruined.
Another way to obtain diameter would be to ask you to measure the circumference of the temple, then divide by pi. Knowing how most people run for the hills when confronted with math, we skipped on this method too.
In the end, we decided that approximating width for diameter is good enough.
Just some more interesting facts from the Keepons universe.
Cheers, The Keepons Team