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NCLE Flashcards

1
Q

synonymous w/ astigmatism

A

Toric

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2
Q

synonymous w/ presbyopia/c

A

multifocal

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3
Q

combination of GP lens center w/ soft lens outer skirt

A

hybrid cl

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4
Q

most frequently prescribed
material containing varying amounts of water
comfort is immediate

A

hydrogel contact lens

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5
Q

soft contact lens
delivers greater oxygen w/o increasing water content( oxygen is more soluble in silicone rubber than water)

A

silicone hydrogel cl

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6
Q

daily
overnight/continuous
flexible

A

soft cl wear schedule

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7
Q

smaller, firmer, durable

A

gas permeable lens

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8
Q

recommended for Pts w/ irregular corneas
excellent for Rxs w/ reading add

A

gp contact lens

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9
Q

nonsurgical way to eliminate/reduce need for eyeglasses or contact lens wear during the day

A

orthokeratology

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10
Q

device/appliance worn overnight to gently reshape the surface of the eye after contact lens are removed
provides clear, unaided vision that can last all waking hours
this is removed in the morning

A

retainer lens

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11
Q

provides sharp visual acuity of GP lens w/ the comfort and wearability of soft contact lens

A

hybrid cl

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12
Q

provide nutrients and oxygen to cornea

A

tears

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13
Q

average central cornea curvature

A

7.8mm

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14
Q

cornea index of refraction

A

1.37

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15
Q

cornea power

A

43.25D

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16
Q

aspheric, gradually flattens from center to edge

A

cornea surface

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17
Q

steepest point of Cornea
may be found in center of cornea

A

corneal apex

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18
Q

has the least amount of curvature
“with the rule” astigmatism

A

180 meridian

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19
Q

has the steepest curvature
“against the rule” astigmatism

A

90 meridian

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20
Q

for irregular astigmatism
rigid lens surface replaces irregular corneal surface
allows light to be bent so it falls more clearly on retina

A

rigid gp lens

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21
Q

~10.6mm

A

cornea vertical diameter

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22
Q

~11.7mm

A

cornea horizontal diameter

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23
Q

center: .5mm-.6mm
periphery: 1.00mm

A

cornea thickness

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24
Q

epithelium
bowman’s membrane
stroma
descemet’s membrane
endothelium

A

layers of cornea

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25
Q

5-6 cells thick
regenerates 3-7 days
regulates flow of water and nutrients into other layers
assists in removing waste from lower layers

A

epithelium

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26
Q

below epithelium
very resilient
once damaged it CANNOT regenerate

A

bowman’s membrane

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27
Q

~90% of cornea’s thickness
formation of dense collagen fibers is responsible for maintaining cornea’s transparency and shape

A

stroma

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28
Q

collagen fiber layers in stroma separate due to excess fluid
results in loss of transparency

A

corneal edema

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29
Q

between stroma and endothelium
like bowman’s in that once damaged it cannot regenerate

A

descemet’s membrane

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30
Q

400,000 - 500,000 cells in a single layer
controls water content of stroma
keeps cornea clear
cells do not regenerate or reproduce

A

endothelium

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31
Q

when endothelium cells change from hexagonal shape to fill in gaps left from lost endothelium cells

A

pleomorphism

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32
Q

endothelium cells change size(expand)
to fill in gaps from lost endothelium cells

A

polymegathism

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33
Q

central posterior or back surface of a lens

A

base curve

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34
Q

longer radius
lower diopter

A

flatter curve

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35
Q

shorter curve
higher diopter

A

steeper curve

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36
Q

oblique like shape
expressed by E value

A

aspheric curve

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37
Q

E value = 0

A

spherical

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38
Q

E value = 0-1

A

elliptical

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39
Q

E value = 1

A

parabolic

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40
Q

E value > 1

A

hyperbolic

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41
Q

decrease diameter
flatten BC

A

compound loose fit

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42
Q

increase diameter
steepen BC

A

compound tight fit

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43
Q

central area of contact lens containing refractive power
needs to be positioned over pupil to provide optimal vision

A

optic zone

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44
Q

flatter
better help align the cornea

A

intermediate curves

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45
Q

outer curves allow for tear flow underneath contact lens

A

peripheral curves

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46
Q

lens thicker at bottom making it heavy
helps prevent rotation while worn
most often used in tori’s and bifocal lens

A

ballasted lens

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47
Q

lens w/ a flat edge
helps position lens on the lower lid
used in some rigid topic and bifocal

A

trunction lens

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48
Q

rigid lens with a single or multiple holes allowing oxygen and/or tear flow

A

fenestration lens

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49
Q

human blinks this many times per minute

A

7-12

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50
Q

tarsal glands located inner edge of eyelid margins
sebaceous/oil secrete lipids into tear film

A

meibomian glands

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51
Q
  1. oil/lipid
  2. aqueous/lacrimal
  3. mucin
A

tear film layers

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52
Q

helps prevent evaporation of tear film
helps prevent tears from flowing onto face

A

oil/lipid tear film

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53
Q

largest volume
secreted by lacrimal gland
mostly water w/ oxygen and nutrients to sustain corneal health
provides moisture to surface of eye

A

aqueous/lacrimal tear film

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54
Q

innermost, hydrophilic layer closest to corneal surface
secreted by conjunctival globlet cells helps anchor tear film to surface of eye

A

mucin tear film

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55
Q
  1. creates smooth surface for light to enter eye
  2. removes foreign bodies, epithelial cells, and mucus from surface of eye
  3. provides lubrication for blinking
A

tear film functions

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56
Q

~7
range from 6.7 - 7.6

A

pH of tear

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57
Q

condition where there is a chronic lack of lubrication and moisture in eye

A

dry eye

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58
Q

more prevalent in women
becomes more common as individuals age

59
Q

Pts who:
wear lenses part time
are exposed to dusty environments
engage in certain contact sports

A

GP lens are not suitable for

60
Q

interpalpebral
keeps lens in a central position
minimizes “interactions” w/ eyelids
(keeps edges thin and tapered)

A

apical clearance

61
Q

lens positioned slightly high on cornea
keeps upper lens edge tucked under upper eyelid
when wearer blinks lens moves as it were “attached” to upper eyelid (movement provides good tear exchange [comfort is improved])

A

apical alignment

62
Q

these have larger diameter and flatter BC

A

apical alignment

63
Q

lens diameter generally should be smaller than visible iris diameter by

64
Q

11mm

A

small iris size

65
Q

11.5mm

A

medium iris size

66
Q

12mm

A

large iris size

67
Q

flatter cornea

A

larger optical zone

68
Q

steeper cornea

A

smaller optical zone

69
Q

GP lens has steeper and steeper curves in secondary

A

reverse curve design

70
Q

12.25mm
.3-.4mm widths

A

typical peripheral curve radius

71
Q

fitting flatter than K creates

A

minus tear lens

72
Q

fitting steeper than K creates

A

plus tear lens

73
Q

adding plastic to front surface of lens edge

A

lenticulation

74
Q

necessary to all + lenses and lenses that are less than -2.5D

A

lenticulation

75
Q

removing excess material on a higher minus Rx for comfort

A

hyperflange

76
Q

astigmatism 0D - 1.50D = .5D flatter than K
astigmatism 1.75D - 2.50D = on flat K
astigmatism >2.50D = use toric design

A

apical alignment fit

77
Q

astigmatism 0D - .50D = on flat K
astigmatism .75D - 1.25D = .25D steeper than K
astigmatism 1.50D - 2D = .50D steeper than K
astigmatism 2.25D - 2.75D = .75D steeper than K
astigmatism 3D -3.5D = 1D steeper than K

A

apical clearance fit

78
Q

GP lenses larger than Corneal GP lenses
rests either on limbral area or scleral area

A

scleral lens

79
Q

8.7mm - 10mm diameter

A

corneal GP lens

80
Q

13mm - 15mm
rest near limbus or where cornea and scleral meet
aka semi-scleral

A

corneo-scleral GP lens

81
Q

15mm - 18mm
covers entire corneal surface
rests on sclera

A

mini scleral GP lens

82
Q

18mm - 24mm
provides greatest amount of clearance between back surface of lens and front surface of cornea

A

true scleral GP lens

83
Q

material’s ability to keep its shape

A

modulus of elasticity

84
Q

are less resistant to stress

A

low modulus of elasticity

85
Q

holds their shape better

A

high modulus of elasticity

86
Q

material(s) that absorb <4% water by weight

A

hydrophobic

87
Q

material(s) that absorb >4% water by weight

A

hydrophilic

88
Q

have negative charge
tend to attract more deposits

A

ionic material

89
Q

low water non- ionic

A

group 1 FDA class

90
Q

high water, non-ionic

A

group 2 FDA class

91
Q

low water, ionic

A

group 3 FDA class

92
Q

high water, ionic

A

group 4 FDA class

93
Q

polymethylmethacryl
first rigid plastics
provided excellent optics
easy to manufacture
does not allow oxygen to pass through
rarely used

94
Q

first GP lens
improved ability for oxygen to pass through
poor wetting (uncomfortable)

A

silicone acrylate

95
Q

flourine added to silicone acrylate lens
helped to be more wettable (improved comfort)

A

flourosilicone acrylate

96
Q

the greater the water content the greater the oxygen permeability
however it causes the eye to dehydrate quicker

A

soft contact lens

97
Q

need frequent replacement (due to being prone to deposits)
larger and more flimsy (harder to apply/remove)

A

cons of soft CL

98
Q

used to measure a GP lens BC
aka spherometer

A

radiuscope

99
Q

can be observed using a flourescent bulb

A

lens blend

100
Q

a well blended lens will reflect a smooth line shaped like a

101
Q

used if refractive astigmatism <.75D

A

spherical lens

102
Q

used if refractive astigmatism >.75D

A

toric lens

103
Q

good for Pts w/ against the rule astigmatism

A

soft toric lens

104
Q

prism ballasting
dynamic stabilization
back surface toricity

A

soft toric lens stabilizers

105
Q

extra thickness on interior(bottom lens)

A

prism ballast

106
Q

double slab off
ideal for against-the-rule astigmatism

A

dynamic stabilization

107
Q

aka biomicroscope
used to evaluate the eye and CL

108
Q

used to highlight areas of disruption on Cornea

A

blue filter

109
Q

used to evaluate CL to Cornea relationship when fitting GP lens

A

blue filter

110
Q

helps highlight area of red

A

green filter

111
Q

light and oculars are focused on same point in slit lamp

A

direct/focal illumination

112
Q

used to observe corneal staining, opacities,deposits, and/or scratches on lenses
used w/ blue filters

A

direct/focal illuminations

113
Q

used to take a general look at the eye

A

diffuse illumination

114
Q

light is spread over a large area

A

diffuse illumination

115
Q

used to evaluate position and movement of soft or GP CL

A

diffuse illumination

116
Q

light is focused next to are being observed

A

indirect illumination

117
Q

light is bounced off of iris so the object or condition on Cornea is lit from behind

A

retro illumination

118
Q

subepithelial and diffuse edema are most easily observed by

A

retro illumination

119
Q

2-3mm slit beam is directed 90 degreees to observer
light is scattered back and forth through cornea

A

sclerotic scatter

120
Q

used to view areas where cornea lacks transparency

A

sclerotic scatter

121
Q

most often used to locate corneal edema

A

sclerotic scatter

122
Q

used when observing tear film under GP lens to determine fit

A

wratten filter

123
Q

in a wratten filter this color means there is space between GP lens and cornea

A

bright green

124
Q

in a wratten filter this color means there is a lack of space between GP lens and cornea

A

dull/dark green

125
Q

lines inside of eyelid, soft, loose tissue

A

palpebral conjunctiva

126
Q

soft, loose tissue extends from inside eyelid to cover sclera

A

bulbar conjunctiva

127
Q

Tear Break Up Time (TBUT) in normal eye

A

10-12 seconds

128
Q

two different k readings in axis
ie 43.00 k@180 / 45.00 k @ 90

A

corneal astigmatism

129
Q

difference in astigmatism between spectacle RX and no difference in k readings
ie RX -3.00 -1.50 x 180
44.0k @ 180 / 44.0k @ 90

A

lenticular / remainder astigmatism

130
Q

Individual w/ against the rule astigmatism

A

good for soft toric lens

131
Q

Individuals w/ oblique astigmatism

A

good for soft toric lens

132
Q

spherical GP lens only

A

correct corneal astigmatism

133
Q

longer radius

A

flatter curve/lower diopter

134
Q

shorter radius

A

steeper curve/higher diopter

135
Q

higher Diopter

A

steeper curve
smaller radius

136
Q

lower diopter

A

flatter curve
bigger radisu

137
Q

Diameter is the same and flattening BC

A

decreases sagital depth

138
Q

increase diameter and keeping BC the same

A

increases sagittal depth

139
Q

thinner CL

A

higher Oxygen transmissibility

140
Q

vertex lens at

141
Q

when vertexing lens minus

A

will be less(higher +)

142
Q

when vertexing lens plus

A

will be higher

143
Q

steeper/smaller sagittal depth

A

tighter fit

NCLE (3 decks)

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