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30 Cards in this Set

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  • Back
A lens clock is used to measure:

A. Astigmatism
B. Pupillary distance
C. Vertex distance
D. Base curve
D. Base curve
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
Equiconcave, flat concave, and meniscus are ALL types of:

A. Minus lenses
B. Plus lenses
C. Astigmatic lenses
D. Spherocylinder lenses
A. Minus lenses
Equiconvex, flat convex, and meniscus are ALL types of:

A. Minus lenses
B. Plus lenses
C. Astigmatic lenses
D. Spherocylinder lenses
B. Plus lenses
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
What is the best base curve for a -3.75D lens?

A. 4
B. 2
C. -4
D. -2
A. 4
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
How much cylinder power is in effect at the specified axis?

A. 0%
B. 25%
C. 50%
D. 100%
A. 0%
A plus lens:

A. Diverges light
B. Converges light
C. Is two prisms placed apex to apex
D. Is concave
B. Converges light
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
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
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
What is the best base curve for a +2.50D lens?

A. 8
B. 6
C. 10
D. 4
A. 8
Eyeglass prescription powers are written in _____.

A. Axis
B. Prisms
C. Diopters
D. Degrees
C. Diopters
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
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
Plus lenses ________ and minus lenses ________.

A. Magnify, minify
B. Minify, magnify
C. Neutralize, verify
D. Myopia, hyperopia
A. Magnify, minify
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
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
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
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
A lens having one concave and one convex surface is called a __________ lens.

A. Biconvex
B. Toric
C. Biconcave
D. Meniscus
D. Meniscus
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
Astigmatism is corrected by a lens having:

A. Plus power
B. Minus power
C. Cylinder power
D. Prism Power
C. Cylinder power
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%
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
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
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
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
How much cylinder power is in effect 90 degrees away from the specified axis?

A. 0%
B. 50%
C. 25%
D. 100%
D. 100%