: Ensure the retailer offers a "no-questions-asked" return or exchange period, as some frames just feel different in person.
: The length of the "arms" from the hinge to the tip. 3. Determine Your Face Fit buying glasses online measurement
: Stand 8–10 inches away from a mirror. Hold a millimeter ruler against your brow. Align the "0" with the center of your left pupil. The measurement directly over your right pupil is your PD. : Ensure the retailer offers a "no-questions-asked" return
If you already have a pair of glasses that fits well, the easiest way to shop is to match those dimensions. Look at the inside of the temple arm (the part that goes over your ear). You will usually see three numbers separated by small squares or dashes (e.g., 52 □ 18 — 140 ). Determine Your Face Fit : Stand 8–10 inches
: Many online retailers (like Warby Parker or Zenni Optical) offer digital tools where you hold a standard magnetic stripe card (like a library card) against your forehead to help their software scale the measurement. Average Range : Most adults have a PD between 54mm and 74mm . 2. Decode Your Current Frame Measurements
The PD is the distance between the centers of your pupils in millimeters. This measurement is critical because it tells the lab where to place the optical center on each lens. If it’s off, you may experience eye strain or blurred vision.