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30 Cards in this Set
- Front
- Back
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A lens clock is used to measure:
A. Astigmatism B. Pupillary distance C. Vertex distance D. Base curve |
D. Base curve
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Transpose the following prescription:
+2.25 +1.75 X 085 A. +2.25 -1.75 X 085 B. -4.00 +1.75 X 175 C. +4.00 -1.75 X 175 D. -2.25 +1.75 X 085 |
C. +4.00 -1.75 X 175
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Equiconcave, flat concave, and meniscus are ALL types of:
A. Minus lenses B. Plus lenses C. Astigmatic lenses D. Spherocylinder lenses |
A. Minus lenses
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Equiconvex, flat convex, and meniscus are ALL types of:
A. Minus lenses B. Plus lenses C. Astigmatic lenses D. Spherocylinder lenses |
B. Plus lenses
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A lens has a front surface power of +2.00D and a back surface power of -8.25D. The corrective power is:
A. -8.25D B. -5.75D C. +2.00D D. -6.25D |
D. -6.25D
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What is the best base curve for a -3.75D lens?
A. 4 B. 2 C. -4 D. -2 |
A. 4
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Using the prescription +2.00 -1.50 X 45, what is the power of the lens at the 90th meridian?
A. 0.5 B. 2 C. 1.25 D. -0.5 |
C. 1.25
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How much cylinder power is in effect at the specified axis?
A. 0% B. 25% C. 50% D. 100% |
A. 0%
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A plus lens:
A. Diverges light B. Converges light C. Is two prisms placed apex to apex D. Is concave |
B. Converges light
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A minus lens:
A. Is thick in the center B. Converges light C. Is thin in the center D. Is two prisms placed base to base |
C. Is thin in the center
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Transpose the following prescription:
-0.75 +3.00 X 180 A. +2.25 -3.00 X 180 B. -0.75 -3.00 X 090 C. +2.25 +3.00 X 180 D. +2.25 -3.00 X 090 |
D. +2.25 -3.00 X 090
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Using the prescription -1.00 -1.50 X 90, what is the power of the lens at the 180th meridian?
A. -2.5 B. -1 C. -0.5 D. -1.5 |
A. -2.5
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What is the best base curve for a +2.50D lens?
A. 8 B. 6 C. 10 D. 4 |
A. 8
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Eyeglass prescription powers are written in _____.
A. Axis B. Prisms C. Diopters D. Degrees |
C. Diopters
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Axis is _______.
A. A notation of position B. A notation of power on a lens C. Always greater than 180 degrees D. Used on spherical Rx |
A. A notation of position
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To switch between minus and plus cylinder forms we use _____.
A. Cylinder conversion B. The cylinder powers formula C. Transposition D. Degree conversion |
C. Transposition
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Plus lenses ________ and minus lenses ________.
A. Magnify, minify B. Minify, magnify C. Neutralize, verify D. Myopia, hyperopia |
A. Magnify, minify
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The spherical equivalent of the lens +1.00 +2.50 x 90 is:
A. +1.50D B. +2.25D C. +2.50D D. +3.50D |
B. +2.25D
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If the prescription is O.D. +1.00 +2.50 x 45, what would be the total power at axis 90?
A. +1.00D B. +2.00D C. +2.25D D. +2.50D |
C. +2.25D
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Which of the following lenses has no power in the 90
A. +2.00 -2.00 x 90 B. +2.00 +2.00 x 180 C. +1.00-2.00 x 45 D. +1.00+1.00x135 |
C. +1.00-2.00 x 45
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Given an Rx with all specifications equal but ground in material of different indices, which set of lenses will be the thinnest?
A. Crown glass B. Polycarbonate C. CR-39 D. Photo-Gray Extra |
B. Polycarbonate
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A lens having one concave and one convex surface is called a __________ lens.
A. Biconvex B. Toric C. Biconcave D. Meniscus |
D. Meniscus
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The dioptric difference between the lenses for the prescription of O.D. +2.00 sph, O.S. +0.50 sph would be:
A. 0.50D B. l.00D C. 1.50D D. 2.00D |
C. 1.50D
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Astigmatism is corrected by a lens having:
A. Plus power B. Minus power C. Cylinder power D. Prism Power |
C. Cylinder power
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Given the prescription +1.00 +1.00 axis 90, how much of the +1.00 cylinder is in effect at axis 90 (the vertical meridian of the lens)?
A. 100% B. 90% C. 50% D. 0% |
D. 0%
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A myope always has in his or her prescription the following kind of power:
A. Minus power B. Plus power C. Cylinder power D. Axis |
A. Minus power
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A hyperope always has in his or her prescription the following power:
A. Minus power B. Plus power C. Cylinder power D. Axis |
B. Plus power
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If a +10D lens is moved 5 mm nearer the eye, it will be about:
A. 0.25D stronger plus B. 0.25D weaker plus C. 0.50D stronger plus D. 0.50D weaker plus |
D. 0.50D weaker plus
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The relationship of front and back curvatures on a spectacle lens will determine:
A. Refractive power B. Segment position C. Effective diameter D. Decentration |
A. Refractive power
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How much cylinder power is in effect 90 degrees away from the specified axis?
A. 0% B. 50% C. 25% D. 100% |
D. 100%
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