Do you wear glasses? Most opticians have eyeglass frames that are all a variation on the standard flat long (side-to-side) rectangle scheme. This may be fine for people with skinny long faces, but it’s unsuitable for other face types.
Rimless lenses can be ANY shape you desire (even shapes that you don’t find at the opticians). This guide inspires you to make your own lens shape to better suit your face. You can use the dummy lens you create to make your actual rimless glasses.