: This is the distance (in mm) between your pupils. Most doctors don't include it automatically, so you may need to ask for it or measure it yourself using a ruler or specialized apps.
: Ensure your script is from within the last 1–2 years. For multifocals, it must include an ADD power, which indicates the additional magnification needed for reading. buy multifocal glasses online
: This measures where the progressive part of the lens starts relative to the frame. Many retailers use a standard "average," but some now offer AI face scans or webcam tools to measure this for a custom fit. : This is the distance (in mm) between your pupils