PD is the distance between your pupils, and it's used to help center a prescription correctly in your frames.
Credit cards have a globally standardized width of 85.60 mm and a height of 53.98 mm. Your interpupillary distance is calculated by detecting the size of the credit card in the image.
The effective error of interpupillary distance is 2mm.
Our measurement results include both single-PD and dual-PD.

Please read the following steps before using our interpupillary distance measurement tool.