ErgonoptiX TTL Guide – How to measure IPD ?
When Ordering new TTL (Through The Lens) type medical loupes, it is important that you provide us with the correct IPD values for your personal fitting so your loupes are perfectly set to your personal features.
You can order all TTL loupes from standard stock for fast delivery, unless you have IPD with high dissymmetry.
This means left and right IPD have a difference of more than 1.5mm. In such a case, you should
order a personalized TTL loupe from us by providing your full IPD details measured by an optometrist. delivery is a bit longer, but you will have a perfect loupe fitted to you.
The best method for getting the best IPD measurement is by optician (usually with special machine)
It is also easy to measure by your self or with help of another person.
See the method here:
https://www.wikihow.com/Measure-Your-Interpupillary-Distance
Details needed to order the correct TTL loupes is:
1. Working distance
2. IPD while looking straight (looking far away)
3. IPD while looking to a point at the correct working distance
4. Tip: pupil distance while looking straight should be about 3.5-4.5mm different from IPD wile looking at working distance, if measured correctly.
5. Important: IPD value for ordering is the IPD while looking at the correct working distance, less 2mm !
Example for correct values:
1. Working distance: 42cm (example !)
2. IPD while looking straight (looking far away): 66mm
3. IPD while looking to a point at 42cm working distance : 62mm
4. Confirm that the differece is between 3.5-4.5mm (in this case 4mm)
5. Important: TTL loupes IPD value for ordering is 60mm (62mm – 2mm)
To make a fully personalized acurate measurement you also measure the exact position of each pupil (because most people have a slight difference between their right and left side)
This value is named OD & OS (Right & Left eye)
You can see some explanation about this here:
https://www.quora.com/What-does-it-mean-if-there-are-two-numbers-for-Pupillary-Distance-on-your-glasses-prescription
Extra details needed to make the fully personalized loupes is:
4. OD & OS (Right& Left eye) While looking straight (looking far away)
5. OD & OS (Right& Left eye) while looking to a point at the correct working distance
This option will be a fully customized loupe.
In case the result is high dissymmetry, a personalized loupe needs to be especially made to order.
It will take a bit longer to deliver (about 1-2 weeks extra), and will have extra costs (about 100 EUR ).
Ask about the terms if you want to know more.
In short, these are the 5 details we need you to provide when ordering TTL loupes:
1. Working distance
2. IPD while looking straight (looking far away)
3. IPD while looking to a point at the correct working distance
If your pupils are not “centered” we also need the values:
4. OD & OS (Right& Left eye) While looking straight (looking far away)
5. OD & OS (Right& Left eye) while looking to a point at the correct working distance
We recomend you ask you local optician to preform these measurments (it only takes them a minute)
Feel free to contact us with any questions
