Using gridpaper as eyeglass background

If you don't have a scale/ruler, then you can use any gridpaper. Please tell us the linedistances, if it is not the usual 5mm-spacing.  And i you don't have gridpaper: here is gridpaper for you to print. If you don't have a printer, we can also send you the gridpaper. Example foto with lens on top of gridpaper: