If you have been wearing glasses that are off by 1.5mm in PD and you keep the old PD measurement you likely feel better wearing the new prescription, since your brain has compensated for this slight difference.2006-04-25
What if my PD is off by 3 mm?
If your PD is off, the “optical center” of your lenses will be, too, and your glasses won't be as effective as they should be. You also need your prescription. Lots of optometrists will give you a copy of your prescription but not include your PD.2017-03-21
Is it OK if pupillary distance is off?
Your Glasses If your pupil distance does not match where the centers of your pupils are, your vision can be affected– Like wearing someone else's glasses! The wrong PD can induce eye strain, fatigue, headaches and blurry vision.2017-12-26