Practice Test Geeks(JCAHPO) International Joint Commission Allied Health Personnel in Ophthalmology Practice Test
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Corrective Lenses Flashcards

7 cards from real JCAHPO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Corrective Lenses flashcards as text

  1. When fitting a patient's progressive lenses, the segment height should be set so that the fitting cross aligns with:

    Answer: The center of the pupil

    The fitting cross (or pupil center dot) of a progressive lens should align with the center of the pupil to position the distance zone correctly.

  2. Which lens coating reduces glare from horizontal surfaces like water and roads by blocking horizontally polarized light?

    Answer: Polarized coating

    Polarized lenses contain a filter that blocks horizontally polarized light, which is the primary component of glare from flat surfaces.

  3. A lensometer reading of 2Δ base-down is found in the left lens. To correct for unwanted prism, the optician should:

    Answer: Raise the optical center of the left lens

    Base-down prism is induced when the optical center is below the pupil; raising the optical center eliminates this unwanted prism.

  4. Which of the following best describes the purpose of the 'boxing system' in opticianry?

    Answer: A standardized frame measurement system using the smallest enclosing rectangle

    The boxing system defines frame dimensions (A, B, DBL, ED) using the smallest rectangle that encloses each lens opening.

  5. A patient's prescription is -6.00 D sphere. Compared to a standard plastic (CR-39) lens, a 1.74 high-index lens would be:

    Answer: Thinner and lighter

    A higher refractive index (1.74 vs. 1.50 for CR-39) allows for a thinner lens and, combined with less material, results in a lighter lens.

  6. What does the term 'optical center' of a lens refer to?

    Answer: The point on the lens through which light passes without prismatic deviation

    The optical center is the specific point on a lens where incident light passes straight through without being deviated by prism.

  7. For a patient with anisometropia (significantly different prescriptions between the two eyes), which lens type helps minimize differential prismatic effect at near?

    Answer: Slab-off (bicentric grinding) lens

    Slab-off (bicentric grinding) creates base-up prism on the more minus (or less plus) lens to compensate for differential vertical prismatic imbalance at near.