Brainscape's Knowledge GenomeTM

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


See full index

CL > SCL > Flashcards

SCL Flashcards

1
Q

Two classes of SCLs

A

HEMA

SiHy - protein-attracting in and of itself, hydrophobic

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

three terms to use when evaluating SCLs

A

centration, coverage, movement

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

Water content range __-__%

-what’s considered “low”? “high”?

A

25-75%

low: 50%

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

Which is true for LOW water content TRADITIONAL SCLs: (lower/higher) Dk, (lower/higher) modulus, (less/more) deposits, used (more/less) for daily CLs

A
  • lower Dk
  • higher modulus (stiffer) - made THINNER
  • smaller pores/deposits
  • used MORE for dailies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which is true for HIGH water content TRADITIONAL SCLs: (lower/higher) Dk, (lower/higher) modulus, (less/more) deposits, used (more/less) for daily CLs

A
  • higher Dk
  • lower modulus- poorer durability/handling, made thicker
  • more deposits, faster dehydration
  • not daily! –>extended wear
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Dk = ?

  • what does the D mean? The K?
  • determined by the content of what 2 things? Which is more permeable?
A

oxygen permeability

  • D = diffusion
  • K = solubility
  • 1) water, 2) silicone - MORE permeable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Dk/T?

A

HOW MUCH O2 is actually getting to the eye

-remember: higher water content lenses need to be made THICKER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Silicone is hydro___, but it is paired w/ hydrogel which is hydro____ to greatly improve ____ permeability

A

phobic
philic

oxygen permeability - Dk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

SCL CT is between 0.-0.

A

0.07-0.09mm (GP was .14)

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

Air optix N+D and dailies total 1 have suuuper high what?

A

Dk

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

4 lenses approved for 7 days/6 nights EW?

A

biofinity, ultra, air optix, acuvue oasys

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

modulus = ____

  • give two high modulus lenses
  • 2 low modulus?
A

stiffness

  • high mod (uncomfortable): N+D, PureVision (~1.50)
  • low mod (slippery, comfortable): AV2, AV oasys (~.30)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

higher water content = (higher/lower) index of refraction?

A

lower (1.38-1.42)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
  • ionic surfaces: (better/worse wettability)

- nonionic surfaces: (better/worse) deposit resistance

A

ionic: better wettability
- BUT: tend to attract proteins
nonionic: better deposit resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

(lower/higher) wetting angles = better surface wettability?

A

lower

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

total one lens - (high/low) Dk SiHy core w/ hydro(philic/phobic) polymer chains bound to the core

A

high Dk, hydrophilic chains

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

MoistureSeal: grows ___ around silicone polymer chains

A

PVP: HIGH Dk, LOW modulus

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

FDA group 1 - water/ionicity?

-do they attract excess deposits? How about dryness?

A

Group 1: LOW water, NON-ionic

-NO: deposit-resistant, least dehydrating

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

FDA group 2 - water/ionicity?

A

Group 2: HIGH water, NON-ionic

-dry out faster

20
Q

FDA group 3 - water/ionicity?

A

Group 3: LOW water, ionic

-PureVision, basically

21
Q

FDA group 4 - water/ionicity?

-GREATEST attraction to _____

A

Group 4: HIGH water, ionic

-greatest attraction to protein

22
Q

4 methods of manufacturing SCLs?

A

spincasting, lathe cutting, cast molding, lightstream technology

23
Q

spincasting: faster spin results in a more (minus/plus) lens

A

minus - THINS it, makes it larger, more minus

24
Q

T/F: Lathe cutting involves a button (like in GPs)
T/F: Water only touches/expands the lens after its manufacture
-which type of lenses are typically lathe-cut?

A

true

true - wicked expensive
-CONVENTIONAL (the old ones that last forever with a bunch of complications)

25
Q

Cast molding: two states?

A

dry: molded, polymerized, hydrated
wet: molded, polymerized, NOT hydrated - lower cost/reproducible

26
Q

Lightstream: mainly which company/lens?

A

ciba dailies - like the total one

-polymerized w/ UV light - falls off and has nice clean edge

27
Q

a lens with a LOW water content usually has a (lower/higher) modulus - this allows it to be made (thinner/thicker)?

A

HIGHER modulus - it has less water so it’s more rigid by nature! Allows it to be made THINNER

28
Q

a lens with a ____ modulus is easier to handle

A

HIGH - more rigid!

29
Q

an SCL with HIGH water content evaporates _____ than a lens with LOW water content

A

FASTER - counter-intuitive. but there’s more water available to evaporate in a high-water-content lens

30
Q

BASE CURVE: tend to be (flatter/steeper) than GPs

-what’s the range?

A

FLATTER. (compensate for increased diameter)

8-9.2mm

31
Q

LD: DIAMETER: usually what range? usually how much LARGER than HVID?
What’s the OZD, usually? Depends on what?

A

LD: 13.5-15.0mm; 1-3 (or 2-3) LARGER than HVID (want 1-1.5mm around limbus)
OZD: 8-10mm, depends on CLP

32
Q

CT range? Is it thicker or thinner for plus powers?

-Does CT increase or decrease w/ higher water content materials?

A
  1. 03-0.10; THICKER for plus powers

- INCREASES

33
Q

T/F: All SCLs are lenticulated.
T/F: The MORE lenticulated a lens is, the LARGER the OZD will be.
-two major aspects affected by edge design?

A

TRUE. They have to be in order to maintain a thin profile.
FALSE. There’s less space for the OZD b/c you put it on the edge!
-comfort, lid interaction

34
Q

4 reasons for using tints? (HEP-C)

A

Handling
Enhancing colors
Prosthetics
Cosmetics (opaques)

35
Q

Enhancing tints c____ with your natural eye color, while opaque tints create a whole ___ color.
-what’s the problem with opaque tints (you should warn your pt, hint: night?)

A

combine, new

-nighttime when pupil dilates: may see BLUR around edges

36
Q

what are some things you can mask/create w/ prosthetic tints?

A

corneal scars, iris defects, pupil occluders (amblyopes)

-VERY expensive/long production time - may be prism ballasted to maintain position

37
Q

Inversion markers should be looked at from the (outside/inside)?

A

OUTSIDE; otherwise they’ll put ‘em in the opposite eye

38
Q

what are the three replacement modalities? [CFD]

A

Conventional
Frequent replacement
Disposable

39
Q

what’s the problem w/ conventional lenses? What’s their typical replacement schedule? Do they require more/less cleaning?

A

more deposits - older lens type! they’re custom (little glass jars) - MORE DEPOSIT PRONE, but lower cost. MORE cleaning

40
Q

frequent replacement lenses: how often do you change them?

-LOWEST _____ rate

A

planned schedule - 2wks-3 mos, worn DW or EW

-lowest COMPLIANCE rate

41
Q

Disposable: can be DAILY (one day)

  • EW: how long?
  • Continuous wear: how long?
A

EW: one week, then chuck em

continuous wear: 1 month nonstop (N+D), then chuck

42
Q

(disposable) dailies - avg WT/day? can you nap?

A

10-14 hrs. No…i mean, 50% more likely for infection

43
Q

(disposable) EW lenses - max day/night WT?

- what additional requirement is inherent in these lenses?

A

7 days/6 nights

-gotta be FDA approved.

44
Q

(disposable) continuous wear - up to how many days max?

- lenses have to be WHAT material to qualify here? Must have a high ___

A

30 days, nonstop

-Silicone Hydrogel - high DK req’d.

45
Q

generally, SiHy lenses have a (higher/lower) wetting angle

A

HIGHER - silicone repels water - which is why they use different processes to make it hydrophilic again

CL (9 decks)

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