question about Pupillary distance measurement?!


Question: Question about Pupillary distance measurement?
i took some pics of me holding the ruler in front of the camera, i got the pd.

i also measured the pd directly by looking in the mirror. it seems that my mirror measurement is about 5 mm or more bigger.

which one is more correct?

2. if the pd is very off from the measurement, what could happen to the person who wears the eyeglasses?

Answers:

The best way is to get a friend to measure it with you looking straight ahead, as if you are looking right through him/her into the distance, certainly you know someone who can operate a ruler. Sometimes, it is actually easier to measure from say, the left edge of the left pupil to the left edge of the right pupil as the sharp line where the pupil meets the iris is much easier to measure than finding the center of the pupil. If there is any doubt, get 2 people to measure and if it is the same, it is probably correct. Even if you are off by a mm, it won't be that big of a deal, glasses shift around on your face by at least this much anyway.

If your measurement is way off, the lenses won't be centered over your eyes which could lead to distortion, headaches, etc. The stronger you prescription is, the more critical this measurement be correct. If it is wrong, it won't damage your vision, just annoying and possibly result in wasting money if the glasses are so far off as to be unwearable.

Added:

To whoever is giving out the thumbs down, the procedure I describe is exactly what the optician did, when he measured my PD. He used a regular ruler, no special instruments involved. I have never heard or experienced the looking in different directions for measuring a PD as one of the answerers said. Certainly it would be better to get the PD number from your optician, but it is totally possible to get a friend to measure it for you.



Dear god this is so wrong.

To measure PD you have to have the person looking in different directions, while the measurer looks in each eye independently. It can't be done correctly by lay-people who haven't a clue how to do it.

I can only assume you are doing this to order glasses off the internet. You are a fool. You have no idea what you are getting and there is no recourse if its wrong - you've taken the measurement yourself after all.

If the PD is off it will disturb vision, can cause headaches and double vision.

Go to a reputable optician and get the job done properly.

Experienced Optician



I agree you better have it measured by your friend or family. If the PD is not accurately measured, the lens will off focal.
You may refer to this article for PD measurement www.neoglasses.com/how-to-measure-pd.htm…



The one from the mirror is more correct as it is life size.
If the pd is incorrect then you may not see well, get eyestrain symptoms and even double vision.




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