Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ophthalmic Optics > B14 Review > Flashcards

B14 Review Flashcards

1
Q

What can you use to measure the curvature of a lens?

A

Lens clock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What can you use to measure the thickness of a lens?

A

Lens caliper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is the thickest part of a plus lens?

A

Center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where is the thickest part of a minus lens?

A

Edge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do you measure monocular PD?

A

Optical center to the center of the bridge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What can you use to measure the vertex distance of glasses?

A

Distometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do you measure seg height for bifocals?

A
  • Deepest part of the lens to the lower limbus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do you measure seg height for trifocals?

A
  • From the deepest part of the lens to 1 mm below the pupillary margin, so that they’re not looking through the intermediate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you measure seg height of PALs?

A
  • Center of pupil to the deepest part of the lens

- add +0.5mm for plastic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is x-ing?

A

Vertical misalign, twisted frame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is “splaying”?

A

Temple spread

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a “skewed bridge”? How do you fix it?

A
  • One lens is higher than the other

- force one side up and one side down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does “variant planes” mean? How do you fix it?

A
  • One lens is infront of the other

- Push-pull method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does pantoscopic tilt mean? What is its relationship to optical center location?

A
  • when the lower rim of the eyewire is closer to the patient’s face than the top
  • for every 2 degrees of PT, you should drop the optical center 1 mm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which lens materials are hypoallergenic?

A

Stainless steel, titanium, nylon, optyl, polyamide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pros/cons of nickel frames

A

Pros: durable, easy to adjust, resists corrosion

Cons: can cause allergic reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pros/cons of Titanium frames

A

Pros: lightweight, strong, hypoallergenic

Cons: expensive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which materials are hard to adjust?

A

Stainless, memory metal, polycarbonate, carbon fiber, optyl (memory plastic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What kind of temple is this?

A

Skull

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What kind of temple is this?

A

Library

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What kind of temple is this?

A

Cable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What do convertible temples look like?

A
  • they can be bent to look like either skulls or librarys
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Best lens material for sports?

A

Polycarb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the relationship between Abbe values and spherical aberrations?

A

Higher Abbe value = less aberrations

25
Q

Which materials have the highest Abbe values?

A

Glass and CR-39

26
Q

Which material has the lowest Abbe value?

A

Polycarb

27
Q

What is the default lens material for adults?

A

CR-39

28
Q

What is the default lens material for kids?

A

Polycarb

29
Q

Which lens material is the heaviest?

A

Glass

30
Q

Which lens material is the lightest?

A

Polycarb or trivex (about the same)

31
Q

What is the cut-off for High index?

A

+/- 4.00, where it becomes lighter than poycarb of equal power (due to allowing for less lens thickness)

32
Q

When is trivex used?

A

Good alternative to Polycarb since it has similar impact resistance and weight but a higher Abbe value (and therefore less abberations)

33
Q

Which lens material is the cheapest?

A

CR-39

34
Q

Which lens material is the most expensive?

A

Glass or hi-index

35
Q

Which lens material is the thickest?

A

Glass

36
Q

Which lens material is the thinnest?

A

Hi-index

37
Q

Which lens materials can be used in rimless or semi-rimlesss frames?

A

Polycarb or trivex

38
Q

What affect (as far as power goes) will pantoscopic tilt have on a plus lens?

A
  • will add plus cyl axis 180

- will add plus spherical power

39
Q

What affect does adding retroscopic (or reducing pantoscopic) tilt have on a plus lens?

A
  • adds minus cyl x 180

- adds minus sphere

40
Q

What affect does adding faceform have on a plus lens?

A
  • adds plus cyl x 090

- adds plus sphere

41
Q

What affect does reducing Faceform have on a plus lens?

A
  • adds minus cyl x 090

- adds minus sphere

42
Q

What affect does increasing pantoscopic tilt have on a minus lens?

A
  • adds minus cyl x 180

- adds minus sphere

43
Q

What affect does retroscopic tilt (or reducing pantoscopic tit) have on a minus lens?

A
  • adds plus cyl x 180

- adds plus sphere

44
Q

What affect does faceform have on minus lenses?

A
  • adds minus cyl x 090

- adds minus sphere

45
Q

What affect does decreasing faceform have on minus lenses?

A
  • adds plus cyl x 090

- adds plus sphere

46
Q

What are the two most important abberations for spectacles?

A
  • field curvature and oblique astigmatism
47
Q

How do we reduce oblique astigmatism in lenses?

A
  • Tscherning’s Ellipse/Ostwalt Curves
48
Q

Plus lenses usually cause what kind of distortion?

A
  • Pincushion
49
Q

Minus lenses usually cause what kind of distortion?

A
  • barrel
50
Q

Some things to know about aspheric lenses?

A
  • cannot use a lens clock since their power changes throughout the lens
  • cannot induce prism, it must be ground in
51
Q

Benefits of aspheric lenses?

A
  • less aberations
  • thinner and lighter
  • reduces the effect of magnification
52
Q

What is Aniseikonia? What usually causes it?

A
  • when the eyes have different image sizes

- anisometropia, or a large difference in Rx between eyes

53
Q

Relationship (approximation) between anisometropia and aniseikonia?

A

1% aniseikonia per 1D of anisometropia

54
Q

At what point does aniseikonia become more of a problem?

A
  • 3-4% size difference (aniseikonia) or 3-4D Rx difference (anisometropia)
55
Q

What are the ANSI standards for sun glasses?

A
  • Z80.3, no glasses should transmit less than 8% of light
56
Q

Which color lenses reduce glare the most? What color of light is filtered by this tint that is thought to be responsible for most glare issues?

A

Brown, blue light

57
Q

Which color lenses increase constrast?

A

Yellow

58
Q

Which color lenses filter all light evenly?

A

Gray

59
Q

Which color lenses significantly affect color vision?

A

Green

Ophthalmic Optics (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions