American Board of Opticianry (ABO) Practice Test

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Prepare for the ABO (American Board of Opticianry) Test with interactive flashcards and hundreds of multiple choice questions. Updated for 2024 to help you excel on exam day

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What parameter is measured by the base curve of a multifocal lens?

  1. a. Vertex compensation formula

  2. b. Apex of the cornea

  3. c. Segment

  4. d. Trivex

The correct answer is: c. Segment

The base curve of a multifocal lens measures the curvature of the lens at the bottom portion, where the near vision segment is located. This curve is important for determining the proper power of the segment and ensuring clear near vision for the wearer. Option A, the vertex compensation formula, is a calculation used to make prescription lenses, and is not directly related to the base curve of a multifocal lens. Option B, the apex of the cornea, is the highest point of the cornea and is not related to the base curve at all. Option D, Trivex, is a type of material used for making lenses and is not related to the base curve either.