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P3 > CL (Soft CL) > Flashcards

CL (Soft CL) Flashcards

1
Q

Parameters (BBL-CLW) (WRF-TIM)

A
  • Base curve
  • Back vertex power
  • Lens diameter, optic zone diameter
  • Center thickness, edge thickness
  • Lenticulation / Edge design
  • Water content
  • FDA groupings
  • Wear schedule approval
  • Replacement modality
  • Tints
  • Inversion markers
  • Manufacturing technique
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2
Q

also referred to as Sagittal depth (sag) or Vault

A

Base Curve

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3
Q

tend to be much flatter than K due to large diameter

A

Base curve

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4
Q

Base curve typical range

A

8.00 to 9.20mm

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5
Q

determined by BC, front curve, CT, n

A

Power

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6
Q

assume that LL is plano for most SCLs

A

Power

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7
Q

Power: effective power not altered by lacrimal lens (True or False)

A

True

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8
Q

larger than RGPs in general

A

Lens diameter/ optic zone

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9
Q

increases stability & comfort

A

Lens diameter/optic zone

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10
Q

Lens diameter/optic zone typical mm

A

13.5 to 15mm

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11
Q

creates greater sag, resulting in need for flatter BC’s

A

Lens diameter/optic zone

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12
Q

decreases tear exchange

A

Lens diameter/optic zone

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13
Q

thinner than RGPs due to decreased fragility of material (greater flexibility)

A

Center & Edge Thickness

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14
Q

affects Dk/L

A

Center Edge & Thickness

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15
Q

Center & Edge Thickness: edge profile may be more important to consider (True/False)

A

True

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16
Q

Min CT = ______, increases for higher water content materials

A

0.03mm

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17
Q
  • due to large diameter, all SCLs are lenticulated to maintain thin profile
  • edge designs vary
A

Lenticulation/Edge design

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18
Q

water is bound within a hydrophilic polymer matrix to provide flexibility & oxygen permeability

A

Water content

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19
Q

The amount of _____ determines material characteristics

A

Water

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20
Q

Water content range

A

Range: 25% to 74%
Low: <50%
High: >50% (FDA)

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21
Q

Water content (Low) (GLUCEF)

A
  • Good durability & handling
  • Fewer deposits
  • Lower Dk
  • Can be made thinner
  • Used more often than daily wear
  • Exception: SiHy
    Range: Low: <50%
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22
Q

Water content (High) (HUMMP)

A
  • Higher Dk
  • Used more often than extended wear
  • More deposits
  • Poorer durability & handling
  • Must be made thicker
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23
Q

Water content: For ___________, less water content means higher silicone content, and therefore higher Dk

A

Silicone hydrogels

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24
Q

Water content
PureVision:
Focus N&D:

A

PureVision: 36% water Dk: 110
Focus N&D: 24% water, Dk: 140

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25
Q

Silicone hydrogels: hydrophobic

A

Silicone

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26
Q

Silicone hydrogels: hydophilic

A

Hydrogel

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27
Q

What is other name for silicone

A

Polydimethylsiloxane

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28
Q

Silicone Hydrogels AerGel Technology (WOSH)

A

-Oxygen
-Water
-Hydrogel matrix
-Silicone matrix

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29
Q

FDA Groupings

A

Group 1: low water, non-ionic
Group 2: high water, non-ionic
Group 3: low water, ionic
Group 4: high water, ionic

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30
Q

In FDA groupings, what groups are non-ionic

A

Group 1 & 2

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31
Q

In FDA Groupings, what groups are ionic

A

Group 3 & 4

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32
Q

In FDA Groupings, what groups are low water

A

Group 1 & 3

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33
Q

In FDA Groupings, what groups are high water

A

Group 2 & 4

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34
Q

Water Schedules: wear during waking hours only, no overnight wear

A

Daily wear

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35
Q

Water Schedules: wear overnight up to 7 days in a row, any lens approved for EW

A

Extended Wear

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36
Q

Wear Schedules: wear continuously up to 30 days in a row, only for silicone hydrogels

A

Continuous wear

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37
Q

Replacement Modality (CFD)

A
  • Conventional
  • Frequent replacement
  • Disposable
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38
Q

lens is replaced when it needs replacing

A

Conventional

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39
Q

if a lens is lost/damaged, a replacement must be purchased

A

Conventional

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40
Q

Conventional SCL typically lasts

A

12 months for a SCL

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41
Q

patient receives one pair of lenses at a time

A

Conventional

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42
Q

more lens care required, more deposit related complications

A

Conventional

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43
Q

also called Programmed Replacement

A

Frequent Replacement

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44
Q

Frequent Replacement: lens is replaced on a regular schedule ___weeks to ____months

A

2 weeks to 3 months

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45
Q

Lens is reused after removal & disinfection

A

Frequent Replacement

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46
Q

confusion with various replacement schedules

A

Frequent Replacement

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47
Q

fewer complications, still requires lens care, more costly

A

Frequent Replacement

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48
Q

one time use, no lens care, most costly, greatest convience

A

Disposable

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49
Q

(Disposable) Daily wear:
Extended wear:
Continuous wear:

A

DW: 1 day
EW: 1 week
CW: 1 month

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50
Q

Tints

A
  • Handling/ Visibility
  • Enhancing
  • Opaque cosmetic
  • Prosthetic masking
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51
Q

can see more easily in case, sink, or counter

A

Handling/Visibility Tints

52
Q

light tints to aid in lens handling

A

Handling/Visibility Tints

53
Q

not meant to change eye color

A

Handling/Visibility Tints

54
Q

can change eye color in light blue irises

A

Handling/Visibility Tints

55
Q

virtually all current lenses have __________

A

handling tints

56
Q

change eye colors of light irised patients

A

Color Enhancing Tints

57
Q

combines with natural eye color to create a new color

A

Color Enhancing Tints

58
Q

Color Enhancing Tints: change eye colors of light irised px

A
  • Blue, green, hazel eyes
  • Will only darken brown eyes
59
Q

tints that change dark irises to other colors: “Brown eyes to blue”

A

Opaque Tints

60
Q

may see some iris through clear pupil

A

Opaque Tints

61
Q

mask underlying iris color, px may notice some blur around the edges

A

Opaque Tints

62
Q

mask underlying disfiguration of the eye (Corneal scars & Iris defects)

A

Prosthetic Tints

63
Q

Prosthetic Tints: what underlying disfiguration of the eye (CI)

A
  • Corneal scars
  • Iris defects
64
Q

can be clear or occluder pupil lens

A

Prosthetic Tints

65
Q

very expensive & long production time, can be painted any color

A

Prosthetic Tints

66
Q

Ciba: Special Eyes Program
CooperVision: Prosthetic lenses
Adventure in colors
Crystal Reflections

A

Prosthetic Tints

67
Q
  • tell a px if a lens is inside-out
  • tells you if lens is inside-out on the eye
A

Inversion Markers

68
Q

many manufacturers now put letters/numbers on their lenses

A

Inversion Markers

69
Q

Lens position & corneal coverage: Vertical & lateral assessments

A
  • Superior-Central-Inferior
  • Temporal-Central-Nasal
70
Q

full corneal coverage is necessary at all times

A

Lens position & corneal coverage

71
Q

Lens position & corneal coverage: Assessment is made in primary gaze

A
  • Eyelids in normal position
  • Head in normal position
72
Q

Lens positioning & corneal coverage: Factors affecting lens position (SEL)

A
  • Sagittal depth
  • Lens diameter
  • Eyelid interaction
73
Q

an assessment of lens movement induced by the normal blink, assessed in primary gaze

A

Blink Movement in Primary Gaze

74
Q

Blink Movement in Primary Gaze acceptable blink movement range ___ to ____mm. At no time should the inferior cornea be exposed during this movement

A

0.5 to 2.0mm of vertical excursion

75
Q

the amount of lag movement on upgaze is assessed

A

Upgaze movement

76
Q

Acceptable amount of upgaze lag movement range

A

0.5 to 2..0mm

77
Q

amount of lens movement on blink while px is looking up should also be made, usually greater than blink movement in primary gaze. How many mm is the acceptable movement up, as long as inferior cornea is not exposed

A

2.0mm

78
Q

an assessment of lag movement induced by lateral eye excursions

A

Lateral lag movement

79
Q

Lateral lens movement on lateral eye excursions range

A

0.5 to 2.0mm

80
Q

Lateral lag movement:
- a _____ fitting lens will not have lateral lag movement
- a ______ fitting lens will lag excessively, exposing some of the cornea

A

tightly, loosely

81
Q

this is a supplemental observation

A

Lateral lag movement

82
Q

the lower lid can be used to manually push upward on the lens to determine if the lens is freely floating on the cornea

A

Push-up movement

83
Q

this test is supplemental

A

Push-up movement

84
Q

Factors affecting lens movement (BELLLL)

A
  • Base Curve
  • Lens diameter
  • Eyelid interaction
  • Lens thickness
  • Lens modulus
  • Lens hydration/dehydration
    Dehydration effect on soft lens parameters:
    -steeper base curve
    -smaller diameter
    -slight decrease in lens power
85
Q

Dehydration effects on soft lens parameters

A
  • steeper base curve
  • smaller diameter
  • slight decrease in lens power
86
Q

Over keratometry mires

A

Auxiliary Observations

87
Q

(Auxiliary observations) Over-keratometry mires
steep fit:
flat fit:

A

Steep fit: blur-clear-blur
Flat fit: clear-blur-clear

Blurring of mires can also be due to lens surface drying

88
Q

Auxiliary observations: Retinoscopy reflex

A

Steep fit: central distortion
Flat fit: inferior distortion

89
Q

Auxiliary observations: conjuctival drag: movement of vessels with tight or adhered lens

A

DDX: Loose conjunctiva

90
Q

Auxiliary observations: what are the indications for tight fitting lenses (BLV)

A
  • Bubbles at limbus indicate tight fitting lenses
  • Vessel blanching & engorgement with tight lenses
  • Lens imprint after removal with tight lenses
91
Q

What are the auxiliary observations

A
  • Over-keratometry mires
  • Retinoscopy reflex
  • Conjunctival drag
    & more
92
Q

What are the soft lens optics (PLAVE)

A
  • Vertexing
  • Lacrimal lens
  • Predicting the OR
  • Effect of lens on Optics
  • Aspheric designs
93
Q

What are the different tints (POCH)

A
  • Handling/Visibility Tints
  • Color Enhancing Tints
  • Opaque Tints
  • Prosthetic Tints
94
Q

What are the Soft lens fit characteristics (BULLPA)

A
  • Lens position & corneal coverage
  • Blink movement in Primary Gaze
  • Upgaze movement
  • Lateral lag movement
  • Push-up movement
  • Auxiliary observations
95
Q

Vertexing: be sure to vertex any meridian _____ or over

A

+4.00

96
Q

the CLP is equal to the vertexed refraction or its ____ equivalent

A

SPH

97
Q

assume that for most soft spherical lenses, the LL = _____, regardless of BC or K-reading

A

plano

98
Q

LL: if SR = -3.00, the above lens is ______

A

optimal

99
Q

Predicting the OR: since there is no LL, the OR is simply the difference between refraction & CLP. Formula for OR

A

POR = SRv - CLP - LL

100
Q

Effect of lens on Optics: in steep lens

A

Steep lens: poor draping, poor VA between blinks

101
Q

Effect of lens fit on Optics: poor draping, poor VA between blinks

A

Steep lens

102
Q

Effect on Lens Fit on Optics: in flat lens

A

poor draping & excessive movement, poor VA right after the blink

103
Q

Effect of Lens Fit on Optics: poor draping & excessive movement, poor VA right after the blink

A

Flat lens

104
Q

Effect of Lens Fit on Optics: poor hydration & optical quality, poor VA between blinks as lens dries

A

Dry lens

105
Q

Effect of Lens Fit on Optics: in dry lens

A

poor hydration & optical quality, poor Va* between blinks as lens dries*

106
Q

Aspheric designs: _______ reduce spherical aberration & may increase depth of focus

A

Aspheric front surfaces

107
Q

improves optical quality, esp for higher powers

A

Aspheric designs

108
Q

may improve vision for low astigmats & early presbyopes

A

Aspheric designs

109
Q

What are Aspheric Designs brands

A
  • Ciba Choice AB
  • Coopervision Frequency Aspheric
110
Q

Aspheric design: light rays converge at meeting area rather than a single focal point

A

Traditional spherical design

111
Q

Aspheric design: focuses light better to a common focal point

A

Frequency 55 Aspheric

112
Q

What is the FDA Group 2 classification for SCL?

A

High water, non-ionic

113
Q

Which replacement modality requires least lens care

A

Disposable

114
Q

Which type of tint is used to help patients with corneal scars or iris defects

A

Prosthetic tint

115
Q

What is the typical diameter of SCL

A

13.50 to 15.00mm

116
Q

The term “vertexing” is applied when prescription is

A

More than +4.00D

117
Q

Which water content category typically has fewer deposits

A

Low water content lenses

118
Q

What range of blink movement is considered acceptable for SCL

A

0.5 to 2.0mm

119
Q

Which is true about lenses with higher content

A

They are more prone to deposits

120
Q

Which tint is NOT designed to change eye color

A

Handling/Visibility tint

121
Q

Which lens fit would result in poor vision between blinks due to poor draping

A

Steep lens fit

122
Q

Which parameter primarily affects the oxygen permeability of SCL

A

Water content

123
Q

tightly fitting SCL may result in

A

Conjunctival drag

124
Q

Which is characteristic of silicone hydrogel lenses

A

Better oxygen permeability with less water content

125
Q

What is the main consequence of a poorly hydrated lens

A

Poor vision between blinks

126
Q

Which tint is primarily used to darken the eye color of light eyed individuals

A

Enhancing tint

P3 (11 decks)

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