Pupillary Distance - How to find it accurately?
Discussion
or do you really need to?
The reason is I've seen some nice new glasses and then did some research and found on line I can buy them from a UK source for less than a quarter the cost of all the Opticians that I've seen them in.
Usually, I'm quite supportive of local shops but this is too much of an increase/saving not to take imo.
The thing is, to order them on line you need to add in you "Pupillary Distance" which seems to be the one measurement the opticians won't /don't give you when you get your eyes tested, the cynic in me now wonders why!!
So, as per subject how can I measure my own and does it have to be mm specific?
The reason is I've seen some nice new glasses and then did some research and found on line I can buy them from a UK source for less than a quarter the cost of all the Opticians that I've seen them in.
Usually, I'm quite supportive of local shops but this is too much of an increase/saving not to take imo.
The thing is, to order them on line you need to add in you "Pupillary Distance" which seems to be the one measurement the opticians won't /don't give you when you get your eyes tested, the cynic in me now wonders why!!
So, as per subject how can I measure my own and does it have to be mm specific?
I think you can do it using a ruler and a mirror.
Put the ruler in front of your face, touching your nose, and look into the mirror. Concentrate on the image from your left eye, and look directly into the middle of your left eye. As you do so, line up the edge of the ruler with your pupil. Then, keeping the ruler still, look using your right eye directly into the reflection of your right eye, and read off the measurement.
PS - I think this would actually also work if you placed the ruler on the mirror, so long as you don't move your head. The key thing is to be stood square in front of the mirror and use each eye to look into it's own reflection one at a time. And make sure you don't move your head or the mirror.
HTH
Put the ruler in front of your face, touching your nose, and look into the mirror. Concentrate on the image from your left eye, and look directly into the middle of your left eye. As you do so, line up the edge of the ruler with your pupil. Then, keeping the ruler still, look using your right eye directly into the reflection of your right eye, and read off the measurement.
PS - I think this would actually also work if you placed the ruler on the mirror, so long as you don't move your head. The key thing is to be stood square in front of the mirror and use each eye to look into it's own reflection one at a time. And make sure you don't move your head or the mirror.
HTH
They were from 'the internet opticians'. I got sunglasses and normal glasses from them a couple of years ago. No complaints about their service.
http://www.theinternetopticians.co.uk/index.php
http://www.theinternetopticians.co.uk/index.php
If you have previously bought glasses from an optician who has also checked your prescription, they should give you your PD measurement if you ask for it. The reason they don't hand them out otherwise is to protect the industry allegedly.
When I bought my glasses online, I got my prescription from specsavers, then went to the local sunglasses hut in the local shopping centre, where the individual serving had no issues with measuring my PD for free. That was after treking around 3 other opticians trying to get my PD done.
When I bought my glasses online, I got my prescription from specsavers, then went to the local sunglasses hut in the local shopping centre, where the individual serving had no issues with measuring my PD for free. That was after treking around 3 other opticians trying to get my PD done.
FamilyDub said:
PD is sometimes printed on the leg of a prescription pair of glasses before the wee square thingy?
Something like '54 [] 17'? 54 is my PD I think.
I'm no optician but I think that's just the frame diameter (54) and bridge width (17) there is usually the arm length somewhere as well. but they are the overall dimensions of the frame, the PD is used to locate the sweet spot on the actual lenses so that it focuses in your eye rather than ear, its part of the lens not the frame.Something like '54 [] 17'? 54 is my PD I think.
Cheers guys, someone also reminded me that I race against an Eye Surgeon so I asked him and here's his comments;
[quote]
look at distance with somebody using a ruler, placed in front of you with a millimetre scale ruler, who aligns his/her line of sight onto the centre of the pupil of your right eye whilst holding the ruler at the 0 point against it (or any other reference) and then shifting to the left eye, as you keep looking straight, to measure the distance on the ruler from the right eye, which is the inter pupillary distance. A measurement of 64-66mm is within expected normal range.
You can average your measurements to 65mm and that would be fine for standard spectacles.
The need to be more accurate depends on whether there are other error multipliers in the optical distortion of your spectacles which are:
-large refractive errors. This means values greater than 2.5 in the first section of your prescription (diopter sphere) or greater than 2.0 in the 2nd half of your prescription (astigmatism).
-varifocal, particularly if the there is astigmatism greater than 1.0
-very large and wide spectacle frame
If you have any of the above, unless the affected eye is a fairly “lazy” eye, you have better chances to feel more comfortable with custom made spectacles than standard ones off the shelf or the Internet. The cost is much greater though.
[/quote]
[quote]
look at distance with somebody using a ruler, placed in front of you with a millimetre scale ruler, who aligns his/her line of sight onto the centre of the pupil of your right eye whilst holding the ruler at the 0 point against it (or any other reference) and then shifting to the left eye, as you keep looking straight, to measure the distance on the ruler from the right eye, which is the inter pupillary distance. A measurement of 64-66mm is within expected normal range.
You can average your measurements to 65mm and that would be fine for standard spectacles.
The need to be more accurate depends on whether there are other error multipliers in the optical distortion of your spectacles which are:
-large refractive errors. This means values greater than 2.5 in the first section of your prescription (diopter sphere) or greater than 2.0 in the 2nd half of your prescription (astigmatism).
-varifocal, particularly if the there is astigmatism greater than 1.0
-very large and wide spectacle frame
If you have any of the above, unless the affected eye is a fairly “lazy” eye, you have better chances to feel more comfortable with custom made spectacles than standard ones off the shelf or the Internet. The cost is much greater though.
[/quote]
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