Contact lens material selection, fitting parameters, and lens-related complication recognition tested on the NBEO.
35 cards · basic cards · AI-written, checked twice. Edit anything.
- What does Dk/t measure for a contact lens?
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Oxygen transmissibility of the lens, accounting for material permeability and lens thickness.- What does Dk measure for a contact lens material?
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Oxygen permeability of the material itself, independent of lens thickness.- Which has higher oxygen permeability: silicone hydrogel or conventional hydrogel lens material?
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Silicone hydrogel.- What monomer forms the base of conventional (non-silicone) soft contact lens material?
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HEMA (hydroxyethyl methacrylate).- In conventional hydrogel lenses, how does water content generally relate to Dk?
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Higher water content generally means higher Dk (oxygen permeability).- What does a steep fluorescein pattern look like under an RGP lens?
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Central pooling (dark area) of dye with a bright peripheral ring, indicating apical clearance.- What does a flat fluorescein pattern look like under an RGP lens?
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Bright central touch with minimal dye pooling and a darker periphery.- What fluorescein pattern indicates a well-aligned RGP lens fit?
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Even, thin, uniform dye distribution across the lens.- Why should sodium fluorescein generally not be instilled while a soft contact lens is on the eye?
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The dye can absorb into and permanently stain the soft lens material.- How is the base curve of an RGP lens typically selected relative to flat keratometry?
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Fit on or slightly steeper than flat K.- What lens movement pattern suggests an RGP lens is fit too steep (tight)?
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Reduced or minimal lens movement with blinking.- What signs suggest an RGP lens is fit too flat (loose)?
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Excessive lens movement and 3 and 9 o'clock corneal staining.- What commonly causes 3 and 9 o'clock staining in RGP wearers?
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Poor edge alignment or incomplete blink coverage causing localized nasal and temporal corneal drying.- What is a Superior Epithelial Arcuate Lesion (SEAL) associated with?
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Silicone hydrogel contact lens wear, often from a tight or stiff lens edge under the upper eyelid.- Contact Lens Acute Red Eye (CLARE) is associated with ____ lens wear and bacterial endotoxins trapped behind the lens.
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extended or overnight
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