Optical MathQuestion 96 of 100
A patient is refracted at a 12 mm vertex with -10.00 D, but the frame sits at 16 mm. Which way does the effective power change, requiring compensation?
a.Toward more minus, so less minus is ordered
b.The lens must gain minus power
c.No change occurs
d.It becomes plus power
Explanation
Moving a minus lens farther from the eye (12 to 16 mm) increases its effective minus power, so a slightly weaker (less minus) lens is ordered to keep the correction accurate at the new vertex distance.
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