A glasses order can contain several small numbers that look as though they belong together. Some describe the product; others describe the wearer or prescription. Put them in the wrong box and a careful style comparison can still become the wrong order.
Give product measurements their own column
A marking such as 52 □ 18–140 describes a frame configuration: lens width, bridge size and temple length. It helps identify and compare frames. It does not tell the retailer the wearer’s pupillary distance.
Use those markings to find a reasonable product shortlist, then keep them with the model and color. Do not enter a lens-width number into the PD field because it is the most legible number on the glasses. Product examples shown in guides are examples, not measurements supplied for you.
Keep the wearer’s PD with its source and purpose
Use measured PD for the person and intended task. It may be recorded as a total value or separate right and left values. Preserve the labels and order provided; do not assume the two sides must match or split a total into equal halves without an appropriate basis.
If you are unsure which measurement belongs to a reading order, ask. Fast requires measured information for the intended task rather than a fixed subtraction from distance PD. If repeated home measurements do not agree or the documentation is uncertain, have the information checked before buying instead of averaging away the disagreement.
Reconcile the records before payment
Compare the original prescription, the PD record and the product selection as three distinct sources. Check that the entered values come from the correct place and belong to the correct wearer. Upload the complete prescription and request review for unresolved instructions.
Fast’s PD guidance and prescription policy explain the ordering responsibilities. Customer-entered prescription or PD mistakes are not covered by free remakes. That is why it is worth stopping for one unclear label. A product page can help you choose a frame; it cannot supply a missing personal measurement.