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?
- Oxygen transmissibility of the lens, accounting for material permeability and lens thickness.
- What does Dk measure for a contact lens material?
- Oxygen permeability of the material itself, independent of lens thickness.
- Which has higher oxygen permeability: silicone hydrogel or conventional hydrogel lens material?
- Silicone hydrogel.
- What monomer forms the base of conventional (non-silicone) soft contact lens material?
- HEMA (hydroxyethyl methacrylate).
- In conventional hydrogel lenses, how does water content generally relate to Dk?
- Higher water content generally means higher Dk (oxygen permeability).
- What does a steep fluorescein pattern look like under an RGP lens?
- 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?
- Bright central touch with minimal dye pooling and a darker periphery.
- What fluorescein pattern indicates a well-aligned RGP lens fit?
- 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?
- 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?
- Fit on or slightly steeper than flat K.
- What lens movement pattern suggests an RGP lens is fit too steep (tight)?
- Reduced or minimal lens movement with blinking.
- What signs suggest an RGP lens is fit too flat (loose)?
- Excessive lens movement and 3 and 9 o'clock corneal staining.
- What commonly causes 3 and 9 o'clock staining in RGP wearers?
- Poor edge alignment or incomplete blink coverage causing localized nasal and temporal corneal drying.
- What is a Superior Epithelial Arcuate Lesion (SEAL) associated with?
- 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.
- extended or overnight