Buying glasses online without PD: what to do first

Check the prescription for a PD entry

PD stands for pupillary distance. Your order needs the measurement for you and the lens purpose you are ordering. Some prescription documents include it; others do not. Read the document for a field labeled PD rather than assuming an unlabeled number is the right one.

Start by asking the prescribing office or an optician whether your measurement is available. If the document is unclear, ask what the entry means before typing it into checkout.

Frame measurements cannot tell you your PD

Numbers such as 52 / 18 / 140 mm describe lens width, bridge width and temple length. They help you compare frame proportions, but they do not supply a measurement between your pupils.

Matching a friend’s frame size, using a number from an old frame or choosing a common PD from a chart does not establish your own PD. Our frame number guide explains the difference between the measurements.

One number and two numbers need a careful check

A PD may be supplied as one total number or as separate right and left measurements. Those separate numbers can differ. Use the values and purpose provided for you; do not turn two entries into identical numbers simply because they look close.

For reading-only glasses, ask your optician which PD applies to the reading prescription. If you have more than one measurement and are unsure which to use, pause the order and ask. Do not calculate a replacement value from an average.

Use the measurement guide when appropriate

Our PD instructions explain the measurement and include a ruler guide. A measurement from an eye-care professional is the most reliable starting point. If measurements disagree or you cannot read the result confidently, have it checked before ordering.

This article is an ordering checklist, not a measurement produced for you. No number on this page should be copied into your prescription order as your own PD.

Keep shopping while you get the missing detail

You can compare frames, colors, dimensions and lens prices while you arrange the measurement. Save frames you like or compare them with a comfortable existing pair. Getting the missing detail first can prevent a rushed decision later.

Before payment, check the current eyeglass prescription, the intended lens purpose, your PD and the complete total. Contact us if the prescription lists an ADD; Fast Eyeglasses currently makes single vision glasses.

Read our frame-fit comparison guide and ordering checklist. If a PD entry is the only thing stopping your order, ask for help before buying rather than guessing.