Hold your iPhone at arm's length and Pupillary Distance maps your face with the front camera. Your PD appears in seconds — no ruler, no guesswork.
HOW IT WORKS
How the Pupillary Distance app works on iPhone
Pupillary Distance is an iPhone app that measures your PD — the millimeter gap between your pupils — using the front-facing TrueDepth camera, so you can order eyeglasses online with confidence. TrueDepth is the same depth-sensing camera that powers Face ID; the app uses AR face tracking to locate each pupil in 3D space and report your far, near, and left/right monocular PD in millimeters.
The camera you already have
Every Face ID iPhone ships with a TrueDepth front camera. Apple uses it to unlock your phone and to map faces for AR. We use that same camera to locate the center of each pupil in three dimensions and measure the distance between them — the same number an optician would record with a pupillometer.
Your pupillary distance is usually between about 54 mm and 74 mm. The app reports your far PD (for distance lenses), your near PD (for reading), and your left and right monocular PD measured from the bridge of your nose. Because the measurement is taken in millimeters from depth data, it's accurate enough to order glasses online.
HOW IT WORKS
A live reading shows your pupillary distance in millimeters as the camera locks onto the center of both pupils.
Get both numbers opticians ask for: your far PD for distance glasses and your near PD for reading.
See left and right monocular PD too, so prescriptions that list each eye separately are fully covered.
Tips for an accurate reading
- Hold the iPhone at about arm's length, roughly level with your eyes.
- Look straight into the front camera and keep your head still while it measures.
- Measure in good, even lighting so your pupils are easy to detect.
- Take off your glasses, and move tinted or reflective lenses out of the way.
- Run the measurement a couple of times — consistent results mean a clean reading.
When the app is the right tool
For ordering everyday eyeglasses or sunglasses online, a TrueDepth PD measurement is fast, private, and always in your pocket — and the app can also suggest frame styles for your face shape. For high prescriptions, progressive lenses, or specialized eyewear, treat the app as a convenient starting point and confirm your PD with an optician. For frame styling, see how the frame recommendations work.
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Your PD, measured
in under a minute.
Pupillary Distance turns your iPhone into an accurate PD meter. Measure once, then order glasses online with confidence.
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