Manufacturing, Inspection, & Modification (Hard Lenses)

Question 1

In the making of concentric style bifocals, the different power zones (distance and near) may be ground on

A. The front surface
B. The back surface
C. Either surface
D. Both surfaces

Answer 1

Both surfaces

Question 2

The addition of fluorine to the gas permeable lens ingredients increases

A. Durability
B. Permeability
C. Optical Quality
D. Wettability

Answer 2

Wettability

Question 3

Which of the following instruments would NOT be used to verify the lens diameter in the office?

A. Diameter gauge
B. Radiuscope
C. Measuring magnifier
D. Projection magnifier

Answer 3

Radiuscope

Question 4

Mounting the lens blank in the lathe so that the face of the button is perpendicular to the spindle is necessary to avoid

A. Heat build up
B. Unwanted prism
C. Cylinder power
D. Warpage

Answer 4

Unwanted prism

Question 5

When reading the radius of curvature of the back surface of a contact lens with the radiuscope, the lens is floated on a drop of liquid to

A. Neutralize the reflection from the front lens surface
B. Keep the front surface clean
C. Keep the lens level
D. Keep the back surface clean

Answer 5

Neutralize the reflecti9n from the front lens surface

Question 6

During the lathing process for toric lenses, cylinder power is generated by

A. Using a cylindrical diamond cutting tool
B. Blocking the lens off center
C. Squeezing the lens in a crimping tool
D. Truncating the lens

Answer 6

Using a cylindrical diamond cutting tool

Question 7

When the lens power is verified, placing the concave surface against the lensmeter aperture will reveal ____________ power.

A. Effefctive
B. Front Vertex
C. True
D. Back Vertex

Answer 7

Back vertex

Question 8

Which of the following polishes should NOT be used to polish gas permeable lenses?

A. Silvo
B. Sil-02-Care
C. Alox
D. X-Pal

Answer 8

Silvo

Question 9

After reducing the overall diameter, which of the following additional modifications are not required?

A. Applying peripheral curves
B. Blending
C. Edge shaping and polishing
D. Changing the base curve

Answer 9

Changing the base curve

Question 10

Removal of plastic from the bottom of a lens to produce a flat edge that will control rotation is called

A. Prism ballast
B. Truncation
C. Base curve
D. Blending

Answer 10

Truncation

Question 11

In-office power changes should be limited to _________D, or less

A. 0.25
B. 0.50
C. 1.00
D. 2.00

Answer 11

0.50

Question 12

When gas permeable are manufactured, which parameter is cut first?

A. Anterior convex curve
B. Central posterior curve
C. CN bevel
D. Posterior peripheral curve

Answer 12

Anterior convex curve

Question 13

After the sharp junctures between curves on the lens posterior are smoothed out, they are called

A. Blends
B. Bevels
C. Lenticulation
D. Apex

Answer 13

Blends

Question 14

Which in-office modification is the easiest to perform?

A. Changing base curve
B. Adding plus power
C. Truncation
D. Adding minus power

Answer 14

Adding minus power

Question 15

Calculation of which lens parameter is NOT under the control of the fitter?

A. Central posterior curve
B. Posterior optical zone
C. Anterior power curve
D. Center thickness

Answer 15

Anterior power curve

Question 16

Polishing the surfaces of rigid gas permeable lenses should be performed

A. Every six months
B. Only when it is needed
C. Every year
D. Never

Answer 16

Only when it is needed

Question 17

Lens blends and Ski Edge can be verified using a

A. Keratometer
B. Junctometer
C. Radiuscope
D. Long fluorescent light blub

Answer 17

Long fluorescent light bulb

Question 18

An in-office modification that can be done to think the edge of a minus lens is the

A. Hyperflange
B. Myoflange
C. CN bevel
D. Ski Edge

Answer 18

CN bevel (anterior bevel)

Question 19

The ideal finished edge thickness for rigid lenses, regardless of whether they are plus of minus, is ___________ mm.

A. 0.08 - 0.12
B. 0.04 - 0.10
C. 0.20 - 0.44
D. 0.50 - 1.0

Answer 19

0.08 -0.12

Question 20

In aspheric lens design, the change in curvature that occurs from the center to the edge to the aspheric zone is called

A. Eccentricity
B. Equilibration
C. Effectivity
D. Enormosity

Answer 20

Eccentricity