This case by default is sized to fit typical drugstore readers – there are parameters to adapt it to the dimensions of your eyewear.

• This is designed for easy printing. Turn off supports in your slicer – they are not needed. A brim might be a good idea depending how good adhesion is.
• The script can engrave some text inside the cover – such as your phone number – in case you leave it behind at the coffeeshop.
• The holes help to reduce weight and noise. There's a setting to eliminate them or reduce their number.
• Glasses have a little flex in them, so if you make the case a bit snug, the springiness of the glasses will hold them in place and prevent them rattling around.
• I have not had problems with this case scratching lenses, but if you're worried, you could make it a touch larger and wrap the glasses in a cleaning cloth before you put them in.

The script displays a sizing guide to let you hold the glasses up to the screen to make sure they will fit. For this to be useful, you will need to scale the display to match real life, as determined by holding a ruler up to the screen.