Supposing the need to compensate for vertex distance is warrented--What would I say (in the real world, not opticianry OptiStudent world) when I actually phone and order the lenses? Let me explain.
Data:
Rx: O.D. + 12.50 + 3.00 x 180
O.S. + 13.50 + 2.50 x 90
Add + 3.25
refracted V.D. 14 mm
fitting V.D. 9 mm.
Ok, the compensated power = +13.33 +3.47 x180. What do I order or answer???????????
Do I tell the lab the compensated power and let them round to dioptric steps or do I round myself prior to calling? If I round what is the correct procedure?
Secondly, (for Boards), should I answer with an answer rounded to dioptric steps? If so, again, what is the correct procedure? I have been taught 2 different ways that can give 2 different cylinder powers. Let me explain. For the OD:
1st Method: +13.33+3.47x180 is rounded before it's put on the optical cross to +13.37 @ 180 and +16.75 @ 090
= +13.37+3.37x180
2nd Method: +13.33+3.47x180 put on the cross as +13.33 @ 180 and +16.80 @ 090 and is rounded now to
= +13.37+3.50x180
I am confused, again. Hopefully, I wrote a followable post! I think the second method is correct. Thanks ya'll!
Bookmarks