The right glasses start with an accurate eye exam, lenses matched to your needs, and frames that fit your face. Kinh Mat Dien Bien Phu helps you move step by step.
The right glasses start with an accurate eye exam, lenses matched to your needs, and frames that fit your face. Kinh Mat Dien Bien Phu helps you move step by step.
Understand PD so lenses are centered — clear vision, less eye strain. Free AI PD measurement in your browser.
Many people think an eye test is only about sphere power. When lenses are made, the lab also needs PD (pupillary distance) to center the lenses — for clear, comfortable vision and less fatigue.
PD (Pupillary Distance) is the distance between your pupils in millimeters. It is required to align the optical center of the lenses with where you actually look.
Single PD (binocular)
Distance from one pupil center to the other. Example: 62 mm.
Dual PD (monocular)
Distance from the nose bridge to each pupil. Example: 30 / 32 mm (OD/OS).
Adults usually fall around 54–74 mm. Children’s PD changes with age.
PD sets where the optical center of the lens sits. If it is off, you can still have problems even when power is correct:
Single PD (OU)
62 mm for both eyes together.
Dual PD
30 mm right eye (OD), 32 mm left eye (OS).
Staff use an autorefractor or a dedicated PD meter. At Dien Bien Phu Eyewear, PD is part of our standard refraction workflow.
Use a mm ruler and a mirror (or a helper). Align zero with one pupil center and read the value at the other. Measure 2–3 times and average.
Far from the shop or lost your slip? Dien Bien Phu Eyewear offers a browser tool using your camera and AI — no photo upload, results in seconds.
Use good lighting, 30–70 cm from the camera. Result is indicative; in-store measurement is best for progressives or bifocals.
A hospital or reputable optical shop reduces decentered lenses. Dien Bien Phu Eyewear at 529 3/2, Ward Vuon Lai, HCMC — refraction and PD by trained staff with French/Japanese-standard equipment. In-store eye tests are free.
Camera + AI, no photo stored. Results in seconds for ordering lenses.
Open PD tool529 3/2, Ward Vuon Lai, HCMC — free in-store eye test
