Quiz 7

Question 1

Consider a tetra -curve GP lens. Which of the following is the flattest curve in this lens?
BCR
ICR
PCR
SCR

Answer 1

PCR

Question 2

Consider a tri-curve GP lens. The overall diameter is 8.80mm. Peripheral curve and secondary curve are both 0.30mm wide. What is the back optic zone diameter?

6. 40mm
7. 80mm
8. 60mm
9. 20mm

Answer 2

7.60mm

Question 3

Consider a GP tri-curve lens. The BCR is 7.80mm . The SCR is 8.80mm. What is the appropriate blend radius between BCR and SCR?

8. 10mm
9. 20mm
10. 30mm
11. 40mm

Answer 3

8.30mm

Question 4

Consider a minus power GP contact ens. Decreasing the overall diameter will _________?

a. Increase the center of thickness
b. Increase the edge thickness
c. Move the center of gravity backward
d. Move the center of gravity forward

Answer 4

Move the center of gravity forward

Question 5

Which of the following is not an option to reduce the edge thickness in high minus power GP lens?
CN bevel
Minus carrier
Plus carrier
Smaller OAD

Answer 5

Minus carrier

Question 6

Your pts. spectacle prescription is -8.00 -5.00 x 180. The vertex distance is 14 mm. What is the correct power at the corneal plane?

• 9.50 -6.50 x 180
• 9.50 -5.00 x 180
• 7.25 -5.00 x 180
• 7.25 -3.75 x 180

Answer 6

-7.25 -3.75 x 180

Question 7

How much corneal astigmatism does a spherical soft lens compensate?
0%
20%
40%
90%

Answer 7

0%

Question 8

How much corneal astigmatism does a spherical GP lens compensate?
0%
20%
40%
90%

Answer 8

90%

Question 9

The BCR of a GP contact lens is 8.00mm. The pts K readings is 7.80mm. What is the power of the lacrimal lens?
-1.00
-0.50
Plano
\+0.50
\+1.00

Answer 9

-1.00

Question 10

Your pts. refraction is -2.00D. The K readings are 44.00D 180/ 44.50 090. A GP contact lens fits 0.50D flatter than flat K. What is the required lens power?

• 0.50
• 1.00
• 1.50
• 2.50

Answer 10

-1.50

Question 11

Your pts Rx. is -6.00D. The cornea is not very sensitive. Which of the following is the best fitting option in case of substantial corneal astigmatism?
Spherical GP lens
Spherical soft lens
Toric GP lens
Toric soft lens

Answer 11

Spherical soft lens

Question 12

Your pts refraction is -1.00-1.75 x 180. Keratometry reveals: 42.50 180/43.00 090. What is the internal astigmatism?

• 0.25 x 180
• 0.75 x 180
• 1.25 x 180
• 1.75 x 180

Answer 12

-1.25 x 180

Question 13

A CL has a diameter of 9.80mm. At the thinnest point (apex) the thickness is 0.10mm. At the thickest point (base) the thickness is 0.50mm. The refractive index is 1.46. What is the prism?

2. 12PD
3. 88PD
4. 74PD
5. 53PD

Answer 13

1.88PD