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pupilsdistanc
If your pupil's distance does not match with your eyeglass where the centers of your pupils are, your vision can be affected– Similar to wearing someone else's eyeglasses. The wrong PD can produce eye strain, fatigue, headaches and blurry vision. If you have a high prescription and the wrong PD these symptoms are often much worse. So, get your exact PD before buying eyewear online.
Once again I fell down the martial arts rabbit hole and am plumbing the murky depths of the internet's various martial arts and fighting crafts echo chambers.
If you're not actively involved and only get up to speed every few years or so, you can see the tide of public opinion flapping worse than my dong while I'm skipping naked down a hallway.