final

Question 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?

Answer 1

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)

Question 2

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

Answer 2

The retina.

Question 3

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

Answer 3

Myopia.

Question 4

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

Answer 4

Providing therapy to help straighten the eyes.

Question 5

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

Answer 5

Cataracts.

Question 6

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

Answer 6

Bridge size.

Question 7

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

Answer 7

Cable temples.

Question 8

Which of these describes a positive face form?

Answer 8

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

Question 9

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

A= 50

B = 45

DBL = 15

ED = 52

Answer 9

65 mm

Question 10

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

Answer 10

The fovea.

Question 11

What is the Law of Refraction?

Answer 11

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

Question 12

What is the wavelength of visible red light?

Answer 12

About 700 nm.

Question 13

Read this prescription:

O.D.: +1.75 – 2.00 x 180

What is the cylinder axis?

Answer 13

180 degrees.

Question 14

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

Answer 14

A kryptok seg.

Question 15

What does a drop ball test measure?

Answer 15

The impact resistance of a lens.

Question 16

What is Prentice’s Rule?

Answer 16

Prism = lens power x decentration in centimeters.

Question 17

Which of these is an advantage of a Fresnel lens?

Answer 17

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

Question 18

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

Answer 18

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

Question 19

Where is the near vision sharpest in a progressive lens?

Answer 19

In the area just below the intermediate progressive corridor area.

Question 20

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

Answer 20

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

Question 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?

Answer 21

4 mm

Question 22

How much is 1 centimeter in inches?

Answer 22

.394 inches

Question 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?

Answer 23

+0.50

Question 24

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

Answer 24

-2.00 -100 x 160

Question 25

What does the final number in this soft contact lens prescription specify? -2.00 -1.25 x 90/8.6/14.2

Answer 25

The lens diameter.

Question 26

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

Answer 26

They can provide sharper vision than soft contact lenses do.

Question 27

What is tempering?

Answer 27

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

Question 28

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

Answer 28

The FTC.

Question 29

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

Answer 29

That it has been heat-tempered or hardened.

Question 30

Which layer of the cornea is the thickest layer?

Answer 30

The stroma.

Question 31

What do the superior and inferior rectus muscles do?

Answer 31

They move your eyes up and down.

Question 32

Which of the tunic layers of the eye includes the ciliary body?

Answer 32

The uveal tunic layer.

Question 33

Which of these refractive errors creates more blur in one axial direction than in another?

Answer 33

Astigmatism.

Question 34

What happens in anisometropia?

Answer 34

Each eye has a different refractive power.

Question 35

Which of these eye diseases stems from a problem with the crystalline lens?

Answer 35

Cataracts

Question 36

What will you use an Amsler grid for?

Answer 36

To diagnose and check the progression of macular degeneration.

Question 37

Which of these is the lightest and strongest metal frame material?

Answer 37

Titanium

Question 38

Which of these frame materials keeps its adjustment well and won’t corrode or get brittle?

Answer 38

Stainless steel.

Question 39

When you examine a pair of glasses, you see the numbers 48-14-120 stamped on them. What measurement does the number 120 represent?

Answer 39

The temple length.

Question 40

Which of these is a typical pupillary distance for an adult?

Answer 40

65 millimeters.

Question 41

What is a three-piece mount?

Answer 41

A style of glasses in which the temples and bridge attach directly to the lenses.

Question 42

What will you use lens axis pliers for?

Answer 42

To turn a lens so it’s aligned correctly in the frame.

Question 43

What happens to the optical center of a lens if you add two degrees of pantoscopic tilt?

Answer 43

It’s lowered one millimeter.

Question 44

What is stereopsis?

Answer 44

Depth perception.

Question 45

How will you adjust a frame if the left lens is farther out than the right?

Answer 45

Bend the left endpiece out.

Question 46

How will you decrease the pantoscopic tilt of a frame?

Answer 46

By bending both temples or endpieces up.

Question 47

What will happen to a frame if you bend the left temple down?

Answer 47

It will raise the left lens.

Question 48

Which UV rays will UV-blocking lenses protect you from?

Answer 48

UVA and UVB rays.

Question 49

What is the name of the refractive error in which the light that enters the eye focuses at two different locations within the eye?

Answer 49

Astigmatism.

Question 50

What is a lens clock used for?

Answer 50

To measure the base curve of a lens.

Question 51

Your client’s prescription is O.D. +2.75 -2.00 x 010. What do you get when you transpose it?

Answer 51

+0.75 +2.00 x 100

Question 52

Somewhere around the age of 40, people begin to lose the ability to focus on near objects. What is this refractive error called?

Answer 52

Presbyopia

Question 53

What is the power of a lens if the light rays passing through the lens focus at a point 10 cm behind the lens?

Answer 53

10 diopters.

Question 54

What is the range of wavelengths in the visible spectrum?

Answer 54

400-700 nm.

Question 55

Which tool will you use to measure the vertex distance of a frame?

Answer 55

A distometer.

Question 56

In the Boxing System, what is the B measurement?

Answer 56

The greatest vertical measurement within the box

Question 57

What frame shape looks best on a person with a base-up triangular-shaped face?

Answer 57

A frame with some heaviness at the bottom and low-mounted temples.

Question 58

What is the name of the instrument that measures corneal curvature?

Answer 58

A keratometer.

Question 59

How is a true minus powered lens typically shaped?

Answer 59

Each side of the lens is concave.

Question 60

If the bottom of a frame is too far from a person’s cheeks, what adjustment should you make?

Answer 60

Increase the pantoscopic tilt.

Question 61

What is the requirement for a lens to pass the drop ball test?

Answer 61

The lens must withstand an impact from a 5/8-inch-diameter, .56-ounce steel ball dropped from 50 inches.

Question 62

In the prescription -2.00 -1.00 x 90, what power is in the 180-degree meridian of the optical cross?

Answer 62

-3.00 diopters.

Question 63

What is the refractive index of crown glass?

Answer 63

1.523

Question 64

What is the prismatic effect when a person reads through a +4.00 diopter lens with an add of +2.00 and the person’s pupil moves down to 3 mm below the seg height? The A measurement is 40 mm, the B measurement is 50mm, and the seg height is 22 mm.

Answer 64

2.4 Δ BU

Question 65

How should you bend a frame if the right lens is higher than the left when you face the patient?

Answer 65

Bend the left temple down or the right temple up.

Question 66

How should you adjust a frame if your client’s glasses slide down the nose?

Answer 66

Narrow the nosepads.

Question 67

What is the reading-only prescription for a prescription of -2.50 -2.00 x75, Add +2.50?

Answer 67

Plano -2.00 x 75

Question 68

A patient has a prescription of +10.00 diopters with a vertex of 12 mm. When you fit the frame on the patient, the frame sits at a vertex of 10 mm. What is the effective power of the lens when the patient wears the glasses?

Answer 68

+9.80 diopters.

Question 69

When white light goes through a prism, it’s dispersed into colors due what type of aberration?

Answer 69

Chromatic aberration.

Question 70

What would you recommend for the base curve for the following lens: -6.00 -1.00 x 090?

Answer 70

+2.75

Question 71

If the prescription for a client’s right eye is +10.00 with an exam vertex of 12 mm, and the fitted glasses have a vertex of 15 mm, which of these is an accurate statement about the effective power of the lens?

Answer 71

It has more plus power.

Question 72

What base curve would you recommend for a lens power +4.00 – 1.00 x 180?

Answer 72

+9.50

Question 73

Your client has the following prescription: O.D. -3.50 -1.00 x 090 O.S. -4.00 -0.75 x 065 ADD +2.50 The client now wants a pair of single-vision reading glasses. What new prescription will you use?

Answer 73

O.D. -1.00 -1.00 x 090 and O.S. -1.50 -0.75 x 065.

Question 74

What is the spherical equivalent of -4.50 -1.50 x 025?

Answer 74

-5.25

Question 75

If a lab grinds a -2.50 lens so that the monocular PD is 10 mm greater than it should be, how much prismatic effect will this induce?

Answer 75

2.5 Δ BI

Question 76

What is the focal length of a +5.00 diopter lens?

Answer 76

.2 meters.

Question 77

Using a lens clock, you determine that the front surface of a lens reads +3.50 and the back surface reads +.0.50. What is the power of the lens?

Answer 77

+4.00

Question 78

Where should you mark the fitting cross of a PAL when you’re fitting a progressive lens?

Answer 78

At the pupil center.

Question 79

What is the total power of a lens if the power at 90 degrees is -2.50 and the power at 180 degrees is +2.00?

Answer 79

+2.00 -4.50 x 180

Question 80

Using a lensometer, you see that the sphere lines in the distance portion of a bifocal lens focus at -3.00. The sphere lines focus in the bifocal segment at +0.50. What is the add power of the lens?

Answer 80

+3.50

Question 81

If you don’t have a metric ruler and you measure a temple length at 6 1/2 inches, what temple length should you order?

Answer 81

165 mm

Question 82

When you’re blocking a lens, what is the decentration per lens given the following information? PD = 60 Frame A measurement = 50, frame B measurement = 40 Distance between the lens centers = 20

Answer 82

5 mm

Question 83

When you’re blocking a right lens, how far and in which direction will you move the decentration mark given these measurements? PD=64 DBL= 18 A measurement = 52

Answer 83

3 mm nasally.

Question 84

What is the amount of horizontal decentration of a lens, given these measurements? Monocular PD = 29 DBC = 60

Answer 84

1 mm

Question 85

How much vertical seg height change will you make when blocking a lens for a person with a bifocal prescription who has a vertical imbalance? Here are your measurements: A measurement = 52 B measurement = 40 Seg height desired = 14

Answer 85

6 mm

Question 86

A person’s distance PD is 2.5 inches. What is this in millimeters?

Answer 86

63.5 mm

Question 87

Given the following information about a lens, what is the horizontal decentration? Monocular PD = 25 Eyesize = 48 DBL = 20

Answer 87

9 mm

Question 88

What is the correct MRP raise if the MRP of a lens needs to be 15 mm, the frame A measurement is 55, and the B measurement is 40?

Answer 88

5 mm

Question 89

What is the effective power of a -5.00 lens prescribed at a vertex distance of 12 mm if it sits at 10 mm from the eye?

Answer 89

-5.56

Question 90

What is the spherical equivalent of this prescription? O.D. -5.00 -2.00 x 100

Answer 90

-6.00

Question 91

Given the following prescription, what is the total vertical imbalance when the person wearing the glasses looks down to read and the reading level of the pupils is 4 mm below the seg line? O.D. +4.00 sphere O.S. +2.00 sphere Add +2.50 B measurement = 50 mm A measurement = 55mm Seg height = 20 mm

Answer 91

1.8 Δ BU.

Question 92

What do you get when you transpose the following prescription? O.S. -1.75 + 5.00 x 030

Answer 92

+3.25 -5.00 x 120

Question 93

The optical center for Fred Brown’s right lens was ground 2 mm more nasally than it should have been. What is the induced prism? The prescription is O.D. +2.50 and O.S. -5.00.

Answer 93

.5 Δ BI.

Question 94

The optical center for Mary Lake’s left lens was ground 3 mm more nasally than it should have been. What is the induced prism? The prescription is O.D. +2.50 and O.S. -5.00.

Answer 94

1.5 Δ BO.

Question 95

The lab mistakenly grinds Tom Green’s glasses so that both lenses are decentered 3 mm temporally. What is the induced prism for the right eye? His prescription is O.D. +1.50 and O.S. -4.25.

Answer 95

.45 Δ BO

Question 96

The lab mistakenly grinds Betty Palmer’s glasses so that both lenses are decentered 3 mm temporally. How much is the induced prism for her left eye? Her prescription is O.D. +1.50 and O.S. -4.25.

Answer 96

1.27 Δ BI.

Question 97

Dr. Smith prescribes glasses for Sam Jones. To achieve the prescribed prism for Sam, how much will you decenter the lens, and in which direction, for the right eye? His prescription is O.D. +3.00, 2 Δ BO and O.S. -2.00, 2 Δ BO.

Answer 97

6.7 mm outward.

Question 98

Dr. Williams prescribes glasses for Dave Johnson. His prescription is O.D. +3.00, 2 Δ BO and O.S. -2.00, 2 Δ BO. How much will you need to decenter the left lens, and in which direction, to achieve the prism prescribed?

Answer 98

10 mm inward.

Question 99

99 Paul Martinez receives this prescription: O.D. +2.00, 1 Δ BI O.S. +4.00, 1 Δ BI How much will you need to decenter the right lens, and in which direction, to achieve the prism that’s prescribed?

Answer 99

5 mm nasally.

Question 100

Louise Longmore has this prescription: O.D. +2.00, 1 Δ BI O.S. +4.00, 1 Δ BI How much will you need to decenter her left lens, and in which direction, to achieve the prism that’s prescribed?

Answer 100

2.5 mm inward.