Did you figure out that the two exercises are the answers to each other?

Do you see why, if the base is UP and something, that the two notations show the same meridian, but if they are DOWN and something then the two meridians are 180 degrees apart?

When choosing OD and OS, identify which quadrant the base is in. U&I is between 0 and 90 (quadrant I) only for the right lens; it is between 90 and 180 (quadrant II) for the left lens; etc.
 
 

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