POST TEST FOR MODULE 31: Measuring Prism in Glasses Catalog
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Section 1
1. The power of the prism in a pair of glasses, as read with a lensometer, is dependent upon:
A. the eyepiece adjustment
B. the diopter power of the lens
C. the position of the lens relative to the lensometer port
D. the frame style
2. In order to accurately measure the horizontal prismatic effect of a given pair of glasses on a particular patient:
A. the lens power must be read first
B. the lenses must be read in the geometric center of the lenses
C. the original prescription must be known
D. the points on the lenses through which the patient sees must be marked
3. When measuring prism in a pair of glasses, the distance between the mark on the right lens and the mark on the left lens should equal:
A. the patient's PD
B. twice the patient's PD
C. half of the bifocal add power
D. DBL minus PD
4. You have lined up a glasses lens in the lensometer so that you are measuring the point through which the patient views. A prism correction is evident if:
A. the intersection of the mires lines up with the center of the target
B. the intersection of the mires does not line up with the center of the target
C. the intersection of the mires does not come into focus
D. the intersection of the mires does come into focus
5. What is the correct prism reading on the right lens pictured below?
A. 3 D base-in
B. 1.5 D base-out
C. 1.5 D base-in
D. 3 D base-out
Section 2
6. The key to recognizing the presence of vertical prism in a pair of glasses is to:
A. read the bifocal power first
B. first subtract half of the cylinder power from the sphere power
C. readjust the lens stage when moving from right lens to left lens
D. leave the lens stage in the same position when checking each lens
7. If the mires have been displaced upward from the center of the target, then the lens may have:
A. base-up prism
B. base-down prism
C. base-in prism
C. base-out prism
8. What is the prism correction that is represented in the graphic below of a left lens?
A. 1.5 D base-down
B. 1.5 D base-up
C. 3.0 D base-down
D. 3.0 D base-up
9. If the right glasses lens has base-up prism, then the left lens must have:
A. base-up prism
B. base-down prism
C. base-down prism or no vertical prism
D. no vertical prism
10. If a prism correction in a glasses lens moves the image of the mires off of the lensometer reticule scale, then a ___ must be used with the lensometer to move the image back onto the scale.
A. 10 D plus lens
B. 10 D minus lens
C. prism
D. Maddox rod
Section 3
11. Mixed prism is a combination of:
A. base-in and base-out prism
B. vertical and horizontal prism
C. base-up and base-down prism
D. vertical prism correction in both lenses
12. Mixed prism causes ______ displacement of the mires from the center of the lensometer target.
A. vertical
B. horizontal
C. vertical and horizontal
D. no
13. Vertical prism is measured from the:
A. lensometer power wheel
B. vertical scale of the lensometer target
C. horizontal scale of the lensometer target
D. lensometer axis wheel
14. What is the prism correction that is represented in the graphic below of a left lens?
A. 2 D base-down, 2 D base-out
B. 2 D base-down, 2 D base-in
C. 2 D base-up, 2 D base-in
D. 2 D base-up, 2 D base-out
15. If the lensometer mires of a right lens are off the target scale to your left, then a ____ must be used to move the mires back onto the scale.
A. base-in prism
B. base-out prism
C. base-up prism
D. base-down prism