Which of the following is an application of Prentice's Rule?

• A. Decentration
• B. Vertical imbalance (2 eyes)
• C. Image Jump
• D. Total prismatic effect (1 eye)

Answer: (A)

Prentice's Rule is used to predict the prism effect created when a lens is decentered. The amount of prism (in prism diopters) equals the decentration distance in centimeters multiplied by the lens power in diopters. So, the direct application is understanding and calculating how much prism appears when a lens is shifted away from the pupil. This is why decentration is the best answer: it embodies the core use of the rule—quantifying induced prism from lens misalignment. Other phenomena like image jump or vertical imbalance relate to the consequences of prism but are not the primary calculation a practitioner uses from Prentice's Rule.