Hi all,
I would like to enquire what is the tolerance level for the amount of horizontal prisms that is present when i measure the progressive lens on the distant zone circle.
What are the limits?
Because i have encountered a few pairs which shows the following readings when i check through the lensmeter (when no prisms were requested) :
Example:
R) 2.5D BI
L) 2.4D BO
Shouldn't they be as close to 0 as possible?
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