Prescription Analysis第 48 / 100 题
A patient needs 3 prism diopters base down in the right lens. If the lens is +2.00 D, how much decentration achieves this (Prentice's rule)?
a.0.67 cm up
b.3.0 cm down
c.1.5 cm (raise the OC 15 mm)
d.6.0 cm down
解析
Prentice's rule solved for decentration: cm = prism / power = 3 / 2.00 = 1.5 cm. To create base-down prism with a plus lens, the optical center is raised 15 mm relative to the pupil.
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