American Board of Opticianry (ABO) Practice Test

Disable ads (and more) with a membership for a one time $2.99 payment

Prepare for the American Board of Opticianry Test with flashcards and multiple choice questions, complete with hints and explanations. Get ready to excel in your exam!

Start Multiple Choice Practice Test
Start Flash Cards

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

A -5.00 lens must be decentered by how many millimeters to induce 2 diopters of base-in prism?

  1. 2mm

  2. 3mm

  3. 4mm

  4. 5mm

The correct answer is: 4mm

To induce prism in a lens, it needs to be decentered. Prism power is directly proportional to the amount of decentration. In this case, a -5.00 lens requires 4mm of decentration to induce 2 diopters of base-in prism. This is because 1 diopter of prism is induced for every millimeter of decentration for a -5.00 lens. Therefore, for 2 diopters, the lens must be decentered by 2mm + 2mm = 4mm.

More Questions Like This