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Flashcards in final Deck (100)
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1

1
Your client’s PD is 62. The frame eyesize is 48, and the DBL is 18. When you block this lens, how much will the decentration per lens be?


2 mm
Remember that the formula is (DBC-PD) ÷ 2 and DBC = DBL + A measurement. The correct answer is: 2 mm (Lesson 19, Chapter 2)

2

What part of the eye meshes with the optic nerve so the eye can send electrical images to the brain?


The retina.

3

Which of these refractive errors is caused by a long eyeball that causes an image to focus in front of the retina?

Myopia.

4


What is the job of an optician who works in orthoptics?


Providing therapy to help straighten the eyes.

5

Which of these conditions is treated by replacing a cloudy crystalline lens?


Cataracts.

6

Which of these measurements will help you ensure that a pair of glasses will be the correct fit for a client’s nose?


Bridge size.

7

Which of these temple styles is best for children’s frames because the temples curl around the ear and are extremely flexible?


Cable temples.

8


Which of these describes a positive face form?

The bridge is farther forward than the sides of the frame front.

9


What is the geometric center distance (GCD) of a frame with the following measurements?

A= 50

B = 45

DBL = 15

ED = 52


65 mm

10


What is the part of the retina where the vision is sharpest?


The fovea.

11

What is the Law of Refraction?

Light bends toward the normal when it moves from a rarer to a denser medium.

12

What is the wavelength of visible red light?

About 700 nm.

13


Read this prescription:

O.D.: +1.75 – 2.00 x 180

What is the cylinder axis?


180 degrees.

14

Which type of bifocal style has a segment in a small round circle?


A kryptok seg.

15

What does a drop ball test measure?


The impact resistance of a lens.

16


What is Prentice’s Rule?


Prism = lens power x decentration in centimeters.

17

Which of these is an advantage of a Fresnel lens?


It’s thinner than a standard high-powered lens or prism.

18


What is Vogel’s formula for calculating the correct base curve for a minus lens?


Base curve = half the spherical equivalent of the lens + 6 diopters.

19

Where is the near vision sharpest in a progressive lens?


In the area just below the intermediate progressive corridor area.

20

Which of these will you do in order to verify a pair of prescription glasses?


Make sure the powers, PD, lens material, base curve, adds, and tints or coatings are all correct.

21

Your client’s PD is 60. The frame eyesize is 50, and the DBL is 18.

When you block this lens, how much will the decentration per lens be?


4 mm

22

How much is 1 centimeter in inches?

.394 inches

23

Sharon’s prescription is +1.50 -2.00 x 85. Her doctor wants to eliminate all the cylinder power. What is the spherical equivalent in Sharon’s new prescription?


+0.50

24

Your client’s prescription is -300 +100 x 70. What numbers do you get when you transpose this prescription?


-2.00 -100 x 160

25

What does the final number in this soft contact lens prescription specify?

-2.00 -1.25 x 90/8.6/14.2


The lens diameter.

26

Which of these is an accurate statement about rigid gas-permeable contact lenses?


They can provide sharper vision than soft contact lenses do.

27


What is tempering?


A process used to harden glass so it can be used in impact-resistant dress lenses.
Correct

28


Which of these organizations created the Eyeglass I and Eyeglass II rules?


The FTC.

29


What does a Maltese cross pattern in a polariscope tell you about a glass lens?


That it has been heat-tempered or hardened.

30

Which layer of the cornea is the thickest layer?

The stroma.