Which statement best describes the effect of increasing PAL power on the lens surface?

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $25.99Unlock all

Prepare for the Ophthalmic Optics Exam. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

Multiple Choice

Which statement best describes the effect of increasing PAL power on the lens surface?

Explanation:
Increasing PAL power makes the surface require a stronger change in curvature from the distance to the near zones. That gradient creates a toric (different curvatures in different meridians) surface, so the magnitude of surface astigmatism grows as the added power increases. In other words, higher add powers heighten the meridional difference on the lens surface, especially toward the periphery, which elevates surface astigmatism. It does not reduce or eliminate aberrations, and it does have an effect.

Increasing PAL power makes the surface require a stronger change in curvature from the distance to the near zones. That gradient creates a toric (different curvatures in different meridians) surface, so the magnitude of surface astigmatism grows as the added power increases. In other words, higher add powers heighten the meridional difference on the lens surface, especially toward the periphery, which elevates surface astigmatism. It does not reduce or eliminate aberrations, and it does have an effect.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy