image jump = the difference in bifocal dimensions? ex:35x22 1/2 of 35 and the sum subtracted from 22?
image jump = the difference in bifocal dimensions? ex:35x22 1/2 of 35 and the sum subtracted from 22?
Image Jump = Add power X Seg Center
Seg Center = Seg Depth - 1/2Seg Width
ok let's say 2.50 add ft35 35x22 2.5x4.5/10 ? is that right or would it be 2.5x17.5/10
Seg Center = 22 - (35/2)
Seg Center = 4.5mm
Now use Prentice's Rule
P = 0.45cm X 2.5
P = 1.13^ which is also called image jump
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