Practice Test GeeksABO - American Board of Optometry Practice Test
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Contact Lens Fitting Flashcards

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

Read the first 7 Contact Lens Fitting flashcards as text

  1. Corneal topography showing an asymmetric bow-tie pattern with skewed radial axes (SRAX) is most suggestive of:

    Answer: Keratoconus

    SRAX on corneal topography, where the bow-tie axes are not aligned, is a hallmark early sign of keratoconus.

  2. A bifocal contact lens using an alternating (translating) design relies on which mechanism for near vision?

    Answer: Lens translation downward on downgaze to position the near segment in front of the pupil

    Translating bifocal lenses shift downward in downgaze so the near segment aligns with the visual axis, similar to an executive bifocal spectacle lens.

  3. The minimum recommended Dk/t for daily wear soft lenses to avoid significant corneal hypoxia is approximately:

    Answer: 24 × 10⁻⁹

    Holden and Mertz established that a Dk/t of ≥24 × 10⁻⁹ is required for daily wear to limit chronic corneal edema to ≤4%.

  4. A patient wearing monthly replacement soft lenses is non-compliant with lens care. Which complication are they at GREATEST risk for?

    Answer: Microbial keratitis, particularly Acanthamoeba

    Poor lens hygiene and improper care (especially tap water use) dramatically increase risk of microbial and Acanthamoeba keratitis.

  5. When fitting a toric soft lens, the practitioner should evaluate lens axis stability after how many blinks?

    Answer: After 10–15 minutes of adaptation and several blinks

    Toric soft lens rotation should be assessed after at least 10–15 minutes of adaptation so the lens has settled into its stable position.

  6. Which condition is an absolute contraindication to contact lens wear?

    Answer: Active bacterial corneal ulcer

    An active corneal infection is an absolute contraindication because lens wear would exacerbate the infection and introduce additional pathogens.

  7. A steep scleral lens fit (excessive vault) over a keratoconic cornea will MOST likely result in:

    Answer: Fogging of vision from a thickened, stagnant fluid reservoir

    Excessive vault creates a thick, stagnant fluid reservoir that scatters light and reduces visual acuity, often described as 'fogging.'