Hi, I am new in the forum Board. I am an optometrist in Singapore. I have a question here. I have a round segment bifocal with me, I need to vertify the PD on this spectacle. Am I suppose to take the Optical Centre of the distant and measure the distance? I have heard that the correct way of measurement is actually to half the segment and then measure the distance, the PD measure suppose to be for near PD instead of distant PD. I am confuse here. Please advice on the correct measurement of the PD and the reason behind.
Thank you
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