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| 1. “Yoked” prism __________________________________. |
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A.
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deviates light equally in the same direction |
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B.
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deviates light equally in opposite directions |
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C.
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causes diplopia |
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D.
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both B & C |
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| 2. Prism thinning is usually ____________________________. |
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A.
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prescribed by the refractionist as part of the patient's Rx |
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B.
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used to challenge an extra-ocular muscles |
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C.
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calculated at the laboratory |
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D.
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applied to glass lenses only |
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| 3. The primary purpose of prism thinning is ______________________. |
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A.
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to reduce differences in thickness between the left and right lens |
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B.
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to reduce differences in thickness between the top and bottom of the lens |
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C.
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to reduce the overall thickness and weight of the lens |
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D.
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both B & C |
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| 4. The curvature of a progressive power lens _________________ towards the bottom of the lens. |
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A.
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increases |
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B.
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decreases |
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C.
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remains stable |
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D.
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may either decrease or increase |
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| 5. Which of the following statements regarding this prescription are true? OU -1.00 sph ADD +2.00 |
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A.
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the combined near power is +2.00 diopters |
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B.
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the combined near power is +1.00 diopters |
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C.
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the combined near power is plano |
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D.
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the combined near power is -1.00 diopters |
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| 6. What factors are generally taken into account when determining if prism thinning will be applied? |
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A.
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the location of the Primary Reference Point (PRP) |
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B.
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the combined near power of the lens |
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C.
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the relative thickness of the top and bottom of the lens |
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D.
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all of the above |
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| 7. The “datum line” is a _______________________________________. |
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A.
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horizontal line passing through the geometric center of the lens |
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B.
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vertical line passing through the geometric center of the lens |
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C.
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equivalent to the ED measurement of the frame |
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D.
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both B & C |
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| 8. Prism thinning may not be applied by some LMS (Lab Management Systems) if the PRP ____________________________. |
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A.
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is located above the datum line |
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B.
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is located on the datum line |
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C.
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is located below the datum line |
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D.
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both A & B |
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| 9. Most patients ___________________________ changes in prism thinning. |
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A.
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are extremely sensitive to |
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B.
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will notice some effect with |
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C.
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will adapt over time to |
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D.
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will not notice |
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| 10. A patient who is sensitive to the addition of prism thinning may report ___________________. |
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A.
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feeling like he “is walking uphill all the time” |
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B.
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feeling like he “is walking downhill all the time” |
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C.
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blurred distance vision |
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D.
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diplopia (double-vision) |
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| 11. A patient who is used to prism thinning may notice its absence in future eyewear by reporting ____________________________. |
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A.
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a feeling like he “is walking uphill all the time” |
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B.
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a feeling like he “is walking downhill all the time” |
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C.
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a feeling the reading area is lower in the frame |
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D.
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diplopia (double-vision) |
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| 12. Generally speaking, the amount of prism thinning usually applied is _____________________. |
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A.
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equal to 1/3 the ADD power |
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B.
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equal to ½ the ADD power |
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C.
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equal to 2/3 the ADD power |
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D.
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equal to the ADD power |
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| 13. Generally speaking, the maximum amount of prism thinning applied should be ____________. |
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A.
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1.00 diopter |
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B.
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1.50 diopter |
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C.
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2.00 diopter |
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D.
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2.50 diopter |
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| 14. Prism thinning should be measured at the _________________. |
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A.
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fitting cross |
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B.
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near verification circle |
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C.
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distance verification circle |
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D.
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PRP (Primary Reference Point) |
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| 15. Unless Rx prism has been ordered, the amount of prism at the PRP of should be ___________. |
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A.
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the same in both lenses |
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B.
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4.00 diopters base up in both lenses |
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C.
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4.00 diopters base down in both lenses |
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D.
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in equal amounts but opposite directions in each lens |
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| 16. When looking through a prism, the eye will rotate towards the _____________. |
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A.
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base of the prism |
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B.
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apex of the prism |
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C.
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mid-point of the prism |
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D.
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optical center of the prism |
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| 17. Prism thinning is generally considered to be a ________________ element of the eyewear. |
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A.
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refractive |
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B.
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cosmetic |
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C.
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prescribed |
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D.
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undesirable |
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| 18. Which of the following Rxs is most likely to have prism thinning applied? |
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A.
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OU -3.50 sph ADD +1.00 |
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B.
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OU -3.50 sph ADD +3.00 |
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C.
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OU -1.50 sph ADD +1.00 |
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D.
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OU -1.50 sph ADD +3.00 |
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| 19. If a patient appears to be sensitive to a change in prism thinning, the eyewear should be _______________________. |
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A.
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reordered with a lower fitting height |
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B.
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reordered with a higher fitting height |
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C.
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reordered with prism thinning equal to the previous pair |
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D.
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reordered with prism thinning greater than the previous pair |
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| 20. The PRP is located ____________________________. |
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A.
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mid-way between the engraved circles on the PAL |
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B.
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4mm above the engraved circles on the PAL |
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C.
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at the fitting cross |
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D.
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2.5mm inset from the fitting cross |
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