With the presence of online ordering, many patients are asking optometrists for a PD measurement.
“PD” stands for pupillary distance, or the distance between the eyes.
While a PD measurement can be performed during your visit to the optometrist’s office, it is not part of the prescription as it has no clinical relevance. A PD should be performed during the fitting of the eyeglasses by an optical dispenser. The PD will differ depending on the purpose of the glasses and the type of lenses.
For example, a set of reading glasses will require a different PD measurement than a pair of driving glasses or a pair of computer glasses.
Watch the video below for more information on pupil distance measurements and other prescriptive lens measurement information.
A PD is also only one component of many measurements that are required during the proper fitting of a pair
- Segment or OC height (determines where the lens will be positioned in the frame);
- Vertex distance (distance between the frame and the cornea);
- Pantoscopic tilt (the amount of tilt on the front of the frame);
- Wrap angle (the amount the frame is curved towards your face);
- Base curve (curvature on the front surface of the lens);
- Frame eye size, width, bridge contour, temple length; and
- Lens type, index and material.
As a PD measurement is not part of the optical prescription, some offices do charge a fee for this supplementary test, but should notify you before hand. Talk to your Doctor of Optometry for more information regarding your PD.