1.
A modern lens has a front surface at +4.00D in the distance portion and +6.25 in the near portion.
the back surface is -3.75 in the horizontal direction and -1.50 in the vertical direction.
what is the base curve of this lens?
2.
You are measuring a manufactured plus-cylinder lens, with your lens clock you measure the front surface and find that the vertical direction is +4.00D, and the horizontal direction to be +5.50D. you then measure the back surface of the spectacles and find all directions to be -6.00D. what is the base curve of this lens?
3.
You are measuring a modern lens, with your lens clock you measure the front surface and find that the vertical direction is +4.00D, and the horizontal direction to be +5.50D. you then measure the back surface of the spectacles and find the horizontal direction to be -6.00D and the vertical direction to be -8.00D. what is the suspected amount of warpage of this lens?
4.
What is the nominal power of the following lens?
F1: +8.00 sph.
F2: -6.50 -2.75 x 180
(select all that apply)
5.
When the pins of the lens clock are placed horizontally on a bifocal lens just above the segment line the lens clock reads +4.00D. When the pins are placed horizontally on the segment, it reads +6.25. what is the add power of this lens?
6.
You are measuring a modern lens using an old lens clock and find that the surface of a polycarbonate lens (n=1.586) is +2.25D. which of the following is closest to the true lens power of that surface
7.
The true power of a high index (1.66) plastic lens is +2.25D. which of the following is closest to the reading you would get with an old lens clock
8.
A bifocal lens with slab-off prism has a front curvature of +6.00D. with the lens clock aligned vertically with the moveable pin on the slab-off line the lens clock reads +9.00D. what is the amount of slab-off prism
9.
A polycarbonate lens (n=1.586) has a power of +6.00D. if the diameter of the lens is 50mm, what is the front sagittal depth of the lens?
10.
How thick is the center of a crown glass lens (n=1.53) going to be if the lens is -10.00D, 60mm in diameter with an edge thickness of 1.2cm
11.
A lens clock with 15mm pin separation measures a rigid gas permeable contact lens. if the thickness is 0.094mm, what would the lens clock dial read
12.
How much does a 3.5 ∆ lens displace an object at 33cm
13.
You find the world's most powerful prism at a sketchy pawn shop. as you are reading the packaging it claims an image displacement of 70 degrees at 1 meter. assuming that the packaging is correct. what would the power of that prism be?
14.
Regarding prism: which of the following is/are correctly matched (select all that apply)
15.
A patient is prescribed horizontal prism as follows, OD 5∆ BO, OS 5∆BO. what is the total prismatic effect?
16.
A patient is prescribed vertical prism as follows, OD 4∆BU, OS 2∆BD (THERE IS MORE THAN ONE CORRECT ANSWER--> select all that apply)
17.
Karen is messing around with her friends. she puts the left lens of her glasses over her right eye and views her friend standing down the hall through the temporal most edge of the lens. She notices that her friend is not in the same spot that she was before. if Karen's glasses are OD +2.00 -1.00 x 180, OS -3.00 -5.00 x 090, 50mm diameter. n=1.53; what is the total prismatic effect and in which direction is her friend displaced.
A.
20∆ BI, friend is displaced to Karen's right
B.
20∆ BI, friend is displaced to Karen's left
C.
7.5∆ BI, friend is displaced to Karen's right
D.
2.5∆ BO, friend is displaced to Karen's left
E.
2.5∆ BI, friend is displaced to Karen's right
18.
What is the power in the horizontal meridian of a -2.00 +4.00 x 150
19.
What is the prismatic effect of a -3.50 +3.50 x 180 when it is decentered upward by 5mm over the right eye
20.
Your patient needs 3∆ BO OD. if her rx is +4.00 -2.00 x 030, how much would you need to decenter the lens in order to accomplish the necessary prismatic effect
21.
An OD Rx calls for 3Δ BO and 6Δ BD. What compounded prism must be ground onto the lens surface to arrive at the desired prescription?
22.
A prescription is ordered as follows: OD +0.75 -2.00 x 180; OS +0.50 -1.50 x 180; PD=62mm. upon the return of the glasses from the lab, the PD is measured to be 66mm. What is the amount of prism induced and does it meet ANSI standards?
CHOOSE 2
A.
B.
C.
D.
E.
Yes it meets ANSI standards
F.
No it does not meet ANSI standards
23.
a lens that has an index of refraction of 1.66, a diameter of 48mm, the apex is 5mm thick and the base is 10mm thick. which of the following is closest to the amount of prism that you would find in the center of the lens.