Checking PALs

[Neophyte Optician]

Newbie question - what's the best way to check a PAL Rx if a patient brings in a pair of glasses that were purchased elsewhere and we don't have the fitting cross for that brand of PAL?

Thanks.

[DanLiv]

If you have a PAL identifier book and can determine the lens design it will tell you the fitting cross location, it's that many mm above the markings. If you absolutely cannot figure it out I would default to neutralizing 6-8mm above the horizontal markings, which assumes a 4-6mm drop and then another couple mm to get into the MRP.

[Neophyte Optician]

If you have a PAL identifier book and can determine the lens design it will tell you the fitting cross location, it's that many mm above the markings. If you absolutely cannot figure it out I would default to neutralizing 6-8mm above the horizontal markings, which assumes a 4-6mm drop and then another couple mm to get into the MRP.

Thanks.

How would I verify if the PD was made properly if we aren't able to figure out what PAL brand that it is? What about checking the prism reference point?

[Robert Martellaro]

Neophyte,

Check out this thread:

https://www.optiboard.com/forums/sho...-New-to-optics

Hope this helps,

Robert Martellaro

[Bhupesh]

You dont necessarily need a layout chart. The info you need is how much the drop is in a particular PAL.
Its designers choice for placement.It amy vary from 0 to 4 mm from PRP. But in most case is 4mm.
If you see any Progressive look for water marks they are 34 mm apart and prp is just hlf way. Above PRP
Is Itting cross which is 4 mm above usually.

Hope this works for you in future.