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NCLE Prep > Contact lens Book Questions > Flashcards

Contact lens Book Questions Flashcards

1
Q

The individual awarded the first patent for a corneal lens made of PMMA was
A. Da Vinci
B. Tuohy
C. Fick
D.Soper

A

Tuohy

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2
Q

Polycon I, the first salicylate lens, was developed by

A

Seidner

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3
Q

The biggest disadvantage of PMMA as a contact lens material is its lack of…

A

Gas permeability

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4
Q

The FDA has been involved in the approval of new contact lens materials since the year

A

1968

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5
Q

Which layer of the cornea makes up 10% of the structure’s total thickness:

A

epithelium

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6
Q

The vertical measurement of the palpebral fissure for an average eye is

A

10mm

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7
Q

The eyelid muscle responsible for closure of the lids is

A

orbicularis oculi

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8
Q

The anterior cornea’s main source of oxygen

A

the atmosphere

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9
Q

a dense opacity of the cornea is called a:

A

leukoma

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10
Q

The goblet cells that secrete mucous into the tear film are located in which structure

A

tarsal plate of the eyeid

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11
Q

The transition zone between the bulbar conjunctiva and the palpebral conjunctiva is called

A

fornix

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12
Q

the middle layer of the three main layers of the globe is mostly responsible for

A

nutrition

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13
Q

pupillary constriction is called

A

miosis

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14
Q

the bacteriocidal ingredient found in the precorneal tear film is

A

lysozyme

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15
Q

Number of extrinsic muscles attached to eye:

A

six

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16
Q

Fovea centralis of the retina contains

A

only cones

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17
Q

the bony orbit of the eye is shaped most like a…

A

Pyramid

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18
Q

The structure that can adjust its focus for various object positions is the

A

crystalline lens

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19
Q

The term that is used to describe both eyes moving in the same direction, as when they both look left or both look right is

A

version

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20
Q

the condition where one eye is turned

A

strabismus

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21
Q

The most refractive optical component of the eye

A

The Cornea

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22
Q

The main function of the eye’s outer layer

A

protection

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23
Q

An opacity of the crystalline lens

A

cataract

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24
Q

loss of vision caused by excessive intraocular pressure is

A

glaucoma

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25
Q

which of the following structures would belong to the adnexa oculi

A

tarsal plate

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26
Q

the corneal layer that consists of a single layer of hexagonal cells is the

A

endothelium

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27
Q

the transitional area that joins the cornea and the sclera is known as the

A

limbus

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28
Q

the levator superioris muscles

A

raises the upper lid

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29
Q

swelling of the corneal tissue, or any, is called

A

edema

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30
Q

inflammation of the mucous membrane that lines the inside of the eyelids and covers the anterior globe except for the cornea is called

A

conjunctivitis

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31
Q

the anterior ciliary arteries terminate at the

A

limbus

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32
Q

aqueous humor is secreted by the

A

ciliary body

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33
Q

all the colors we perceive are produced by the different photopigments found in the retinal cones

A

3

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34
Q

through strong aphakic spectacles, a patient will see an object

A

33%

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35
Q

rays if light striking a spectacle lens at its edge create … or distortion

A

aberration

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36
Q

… is a moderate to high refractive difference in the powers of the two eyes

A

anisometropia

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37
Q

through spectacles, the astigmatic patient with “against-the-rule” astigmatism will view a square as follows

A

the square will appear slightly elongated in the vertical meridian

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38
Q

the visual error caused by a cylindrical crystalline lens is known as … astigmatism

A

lenticular

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39
Q

The practitioner should suspect … astigmatism if there is a difference between the amount of cylinder found by keratometry readings and the amount of cylinder found by refractometry

A

internal

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40
Q

When myopic patients view an object at near through their spectacles, the prism created through the spectacles is

A

base-in

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41
Q

a … person must accommodate more when viewing near objects through their contact lenses vs spectacles

A

myopic

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42
Q

… results when the cornea has been damaged by trauma, inflammation or scar tissue

A

irregular astigmatisn

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43
Q

objects in the field of vision of a high myope are … when spectacles are worn

A

minified

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44
Q

… is a developmental anomaly of the cornea that results in irregular myopic astigmatism

A

keratoconus

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45
Q

when decompensation of the .. occurs, aqueous humor leaks into the anterior layers of the cornea forming bullae

A

conjunctiva

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46
Q

In the latter stages of keratoconus, the following may be observed

A

Munson’s sign
distorted mires
corneal opacities
Fleischer’s ring

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47
Q

Which of the following conditions is a contraindication to contact lens wear

A

serve blepharitis

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48
Q

… lenses are used on patients with recurrent epithelial erosions

A

bandage

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49
Q

which of the following patients will experience the most image magnificaton

A

hyperope wearing spectacles

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50
Q

fitting a rigid contact lens steeper than the flattest corneal meridian will introduce … power into the lacrimal

A

plus sphere

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51
Q

The preferred method of vision correction in keratoconus is

A

rigid contact lenses

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52
Q

the normal blink rate is approximately … times per minute

A

12

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53
Q

for patients with a moderate amount of corneal astigmatism (between one and two diopters), which lens type will provide the crispest, most stable vision

A

rigid spherical

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54
Q

usually causes photophobia, itching, lacrimation, and burning

A

respiratory allergies

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55
Q

predisposes the eye to drying due to proptosis

A

thyroid disease

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56
Q

causes changes in the fluid balance of the body

A

lanoxin

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57
Q

is a systemic drug used in the treatment of acne

A

Accutane

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58
Q

may cause blurred vision due to its direct action on accommodation

A

donnatal

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59
Q

The keratometer is patented and trademarked by

A

reichert

60
Q

As light waves travel away from a source they become gradually

A

flatter

61
Q

Optical infinity is considered

A

20

62
Q

Point at which light rays converge is called a

A

focus

63
Q

The term to describe the amount of curvature of a light wave is

A

vergence

64
Q

the unit of measurement for vergence is

A

diopter

65
Q

a light wave that has traveled 50cm from a point source will have a vergence of

A

+2.00
D=1/d
D=1/0.5mm

66
Q

Chapter 4

A
67
Q

When classic keratometry is performed by having the patient sight on the mirrored image of their eye, alignment of what is accomplished?

A

The optical axis with the visual axis

68
Q

An early investigator that studied the curvature of the cornea was ____________________

A

Placido
Helmholtz
Javal

69
Q

The doubling device of the keratometer is necessary due to__________________

A

fine tremor of the eye.

70
Q

The index of refraction used to calibrate the keratometer is __________

A

1.3375

71
Q

The size of the mire (target) on the front of the keratometer is____________

A

64.0mm

72
Q

The distance from the front of the keratometer to the front of the cornea when the instrument is in focus is ____________

A

75.0mm

73
Q

The eyepiece of the keratometer should be focused _____________.

A

daily

74
Q

The keratometer derives its measurement of a meridian from how many points on the cornea?

A

2

75
Q

The range of curvatures the keratometer can measure without auxiliary lenses is _____________

A

36.00D to 52.00D

76
Q

The chord length of the mire measured by the keratometer without auxiliary lenses is ____________

A

3.8mm to 26mm

77
Q

The keratometer eyepiece if not properly focused can cause______________

A

errors in correctly reading curvature

78
Q

In addition to measuring the cornea, the keratometer can be used to________________________

A

check the curvature of a contact lens

79
Q

Steeper curvatures than normally readable with the keratometer can be taken by adding to the front of the instrument a _______________

A

Plus (+) 1.25 trial lens

80
Q

If the whole mire is reflected from the apex _______________

A

the reading will be too flat

81
Q

When a part of the mire is reflected from the transitional zone ___________

A

an inaccurate reading is taken

82
Q

Errors in keratometry occur _____________

A

in keratoconus and irregular astigmatism

83
Q

When the keratometer is properly aligned in front of an eye, the patient will see ___________________

A

a green light

84
Q

The axis of corneal astigmatism when taking a “K” reading______________

A

is the first thing to align

85
Q

The amount of corneal astigmatism

A

is the difference between the reading on the horizontal and vertical drums

86
Q

When the keratometer is out of focus on the cornea ________________________

A

the lower right mire is doubled

87
Q

When measuring the horizontal meridian with the keratometer _____________________

A

the plus mires are superimposed

88
Q

Another name for the slit lamp is the _____
A) biomicroscope
B) phoropter
C) optic spherometer
D) radius gauge

A

A) biomicroscope

89
Q

The historical development of the slit lamp dates back to
A) 1801
B) 1891
C) 1931
D) 1951

A

B) 1891

90
Q

A contact lens fitter uses the slit lamp to view all of the following, EXCEPT
A) the fundus
B) corneal scars
C) corneal neovascularization
D) the conjuctiva

A

A) the fundus

91
Q

The slit lamp is used in the evaluation of which fitting characteristic(s) of soft lenses?
A) Centration
B) Movement
C) Corneal coverage
D) All of the above

A

D) All of the above

92
Q

The two main parts of the biomicroscope are the
A) microscope and chin rest
B) microscope and light source
C) eye piece and power drum
D) light source and joystick

A

B) microscope and light source

93
Q

Which magnification would be appropriate for performing a general survey of the eye at the beginning of a slit lamp exam?
A) 6x
B) 15x
C) 25x
D) 40x

A

A) 6x

94
Q

What angle will the beam and microscope form during most illumination procedures?
A) 25*
B) 45*
C) 60*
D) 90*

A

B) 45*

95
Q

Which slit lamp illumination can be used without the aid of the microscope?
A) Specular reflection
B) Sclerotic scatter
C) Diffuse
D) Retro

A

C) Diffuse

96
Q

Which slit lamp illumination is performed with the microscope placed precisely along the angle of the reflected light from the eye?
A) Specular reflection
B) Sclerotic scatter
C) Optic section
D) Diffuse

A

A) Specular reflection

97
Q

When diffuse illumination is used in conjunction with fluorescein, what filter should be employed?
A) Blue (ultraviolet light)
B) Red-free (green light)
C) Diffuse
D) No filter (white light)

A

A) Blue (ultraviolet light)

98
Q

When an optic section is used in conjunction with fluorescein, what filter should be employed?
A) Blue (ultraviolet light)
B) Red-free (green light)
C) Diffuse
D) No filter (white light)

A

D) No filter (white light)

99
Q

A spherical RGP lens fit on K shows fluorescein pooling under the superior and inferior portions of the contact lens, and a dark band of minimal fluorescein horizontally. What kind of astigmatism does this pattern represent?
A) With-the-rule
B) Against-the-rule
C) Residual
D) Oblique

A

A) With-the-rule

100
Q

A back toric rigid contact lens fit on K to conform to each corneal meridian will show a fluorescein pattern that is
A) concentrated under the center of the lens
B) concentrated under the edge of the lens
C) evenly distributed
D) vertically oriented

A

C) evenly distributed

101
Q

The most useful slit lamp illumination to view gross cornea edema from rigid lens wear is
A) retro
B) direct
C) indirect
D) sclerotic scatter

A

D) sclerotic scatter

102
Q

Which of the following is the most likely cause of 3 and 9 o’clock staining?
A) Inadequate blinking
B) Base curve too flat
C) Dk of lens material too low
D) Base curve too steep

A

A) inadequate blinking

103
Q

An arc stain seen on the cornea under the peripheral or intermediate portion of a contact lens means that
A) 1, 2 1: bevels are too sharp
B) 1, 3 2: lens needs to be blended
C) 2, 3 3: base curve is too flat
D) 3, 4 4: lens is too large

A

A) 1, 2 1: bevels are too sharp

104
Q

What filter is used to improve detection of corneal vascularity?
A) White
B) Yellow
C) Blue
D) Green

A

D) Green

105
Q

The slit lamp illumination that gives an overall assessment of the contact lens fit, but no fine detail, is
A) direct
B) diffuse
C) retro
D) sclerotic scatter

A

B) Diffuse

106
Q

What color filter enhances the fluorescein pattern behind a rigid lens containing a UV blocker?
A) Grey
B) Green
C) Red
D) Yellow

A

D) Yellow

107
Q

Tear break-up time (BUT) is verified with what slit lamp illumination?
A) Indirect
B) Direct
C) Scatter
D) Retro

A

B) Direct

108
Q

Which of the following is an abnormal tear break-up time?
A) 5 sec
B) 15 sec
C) 20 sec
D) 30 sec

A

A) 5 sec

109
Q

The green filter is used in conjunction with which slit lamp illumination?
A) Specular reflection
B) Conical beam
C) Indirect
D) Optic section

A

C) Indirect

110
Q

The slit lamp illumination that shows the entire contact lens, movement, and centration is
A) ratio
B) direct
C) indirect
D) diffuse

A

D) Diffuse

111
Q

The slit lamp illumination where a narrow beam of light bisects the corneoscleral juncture is
A) oscillatory
B) indirect retro
C) sclerotic scatter
D) transverse axial

A

C) sclerotic scatter

112
Q

Staining at the inferior portion of the cornea of a soft lens wearer is usually caused by
A) improper lens removal
B) a loose lens
C) a tight lens
D) a lens that is too large

A

A) improper lens removal

113
Q

Under slit lamp evaluation with fluorescein, corneal area that appear dark and do not hold stain during blinks are most likely
A) dry spots
B) verrucae
C) punctates
D) infiltrates

A

A) dry spots

114
Q

With a rigid lens in place, a fluorescein pattern shows a narrow band of dark vertically, and pooling horizontally. This is indicative of
A) a spherical base curve on a spherical cornea
B) a spherical base curve on a with-the-rule cornea
C) a spherical base curve on an against-the-rule toric cornea
D) a toric base curve on a toric cornea

A

C) a spherical base curve on an against-the-rule toric cornea

115
Q

A rigid lens showing apical touch indicates a
A) flat fit
B) steep fit
C) large fit
D) small fit

A

A) flat fit

116
Q

A rigid lens showing apical pooling indicates a
A) flat fit
B) steep fit
C) large fit
D) small fit

A

B) Steep fit

117
Q

An hour glass fluorescein patten with an RGP lens fit on K indicates
A) a steep fit
B) a flat fit
C) with the rule astigmatism
D) against the rule astigmatism

A

C) with the rule astigmatism

118
Q

For most illuminations the angle between the beam and the scope is about
A) 30 degrees
B) 45 degrees
C) 90 degrees
D) 75 degrees

A

B) 45 degrees

119
Q

To view corneal neovascularity, what slit-lamp illumination is the best one to use?
A) Direct
B) Indirect
C) Retro
D) Diffuse

A

B) Indirect

120
Q

The slit-lamp beam is placed behind the area being studied with what illumination?
A) Retro
B) Indirect
C) Sclerotic Scatter
D) Diffuse

A

A) Retro

121
Q

The rigid contact lens material used widely in the 1950s, ’60s and ’70s was:
a) silicone acrylate
b) polymethylmethacrylate
c) cellulose acetate butyrate
d) none of the above

A

b) polymethylmethacrylate

122
Q

A lens fit with a base curve steeper than the flattest K with a diameter of 8.5mm would follow which fitting philosophy?
a) corneal alignment b) 3-point touch
c) apical clearance d) none of the above

A

c) apical clearance

123
Q

A typical optical zone diameter of a corneal alignment fit would be:
a) 6.5mm b) 7.0mm
c) 7.5mm d) 8.0mm

A

d) 8.0mm

124
Q

A rigid lens which flexes upon the eye would be best corrected by going:
a) steeper b) steeper and thicker
c) flatter d) flatter and thicker

A

d) flatter and thicker

125
Q

A patient with an upper lid that does not cover any portion of the superior portion of the cornea would be best fit:
a) steeper than K with a small diameter
b) flatter than K with a large diameter
c) on K with an 8.8mm diameter
d) none of the above

A

a) steeper than K with a small diameter

126
Q

A -10.00D Rx for a spectacle correction would most likely need a contact lens with a power of:
a) -8.00D b) -9.25D c) -10.50D d) -11.75D

A

b) -9.25D CAP closer add plus

127
Q

A patient fit with a base curve of 43.00D and a power of -3.00D and then refit with a base curve of 43.50D would require a new power of:
a) -2.50D c) -3.50D b) -2.75D d) -4.00D

A

c) -3.50D SAM steeper add minus

128
Q

A patient with a corneal toricity of 4.50 diopters would be best suited with a base curve that is:
a) 1.00 diopter steeper than K
b) 1.50 diopter steeper than K
c) toric
d) none of the above

A

c) toric

129
Q

A patient with a base curve of 42.75D, power of -3.00D, if refit with a lens of base curve of 43.50D, would then require a power of:
a) -2.50D c) -3.75D b) -3.50D d) none of the above

A

c) -3.75D SAM steeper add minus

130
Q

When fitting rigid lenses, residual astigmatism is most often caused by:
a) high refractive cylinder
b) a toric contact lens
c) corneal cylinder against-the-rule
d) a difference between refractive and corneal cylinder

A

d) a difference between refractive and corneal cylinder

131
Q

When using original K readings to refit a former PMMA wearer with gas permeable lenses, it is best to refit:
a) immediately
b) after seven days of no contact lens wear
c) after one month of no contact lens wear
d) none of the above

A

a) immediately

132
Q

A patient fit 0.50D flatter than K with a contact lens power of -1.00D would most likely have a spherical component of ___ in their spectacle Rx, when in minus cylinder form.
a) -0.50D b) -1.50D c) -2.00D d) none of the above

A

a) -0.50D FAP flatter add plus

133
Q

To achieve apical clearance with a rigid gas permeable lens of 8.5mm diameter, fit on a cornea of average size, the base curve should be:
a) on K b) steeper than K
c) flatter than K d) none of the above

A

b) steeper than K

134
Q

A patient with an Rx of +3.00 +0.50 x90 fit 0.50D flatter than K would require a power of:
a) +3.00D b) +3.50D c) +4.00D d) none of the above

A

c) +4.00D FAP flatter add plus

135
Q

Which of the following terms is associated with the corneal alignment fitting philosophy?
a) central pooling b) intrapalpebral fit
c) upper lid attachment d) 3 point touch

A

c) upper lid attachment

136
Q

A patient with an Rx of +2.00 -1.00 x90 and K readings of 44.00 @180/43.00 @90 reveals residual astigmatism of plano -2.00 x 180. A possible explanation for this is:
a) normal residual astigmatism
b) a steeply fitted contact lens
c) a warped contact lens
d) none of the above

A

b) a steeply fitted contact lens

137
Q

A patient wearing a 43.00D base curve, 9.0mm diameter, 7.0mm optical zone diameter requires a change to a 9.5mm diameter with a 7.5mm optical zone diameter. To keep the base curve corneal bearing relationship the same, the new base curve would need to be:
a) 42.50D b) 42.75D c) 43.50D d) 43.75D

A

a) 42.50D

138
Q

An Rx of -2.00 -1.50 x180 and K readings of 43.00 @180/46.00 @90 would have a calculated residual astigmatism of:
a) +1.50 x180 b) +2.00 x90
c) +1.50 x90 d) + 1.00 x180

A

a) +1.50 x180

-1.50 - (-3.00)

139
Q

The optical zone diameter of a rigid contact lens is generally:
a) 3.0mm smaller than the total diameter
b) 3.5mm smaller than the total diameter
c) 4.2mm smaller than the total diameter
d) none of the above

A

d) none of the above - The OZ is generally 1.0mm to 1.5mm smaller

140
Q

Any ophthalmic lens moved closer to the eye becomes effectively:
a) flatter b) steeper c) more plus d) more minus

A

More minus

141
Q

The apical clearance fitting philosophy requires a lens that positions:
a) centrally, with upper lid attachment
b) centrally and intrapalpebrally
c) superiorly, with upper lid attachment
d) superiorly and intrapalpebrally

A

Centrally and intrapalpebrally

142
Q

A diagnostic lens with a base curve of 7.67mm and an optical zone diameter of 7.6mm fits too tight. Which of the following changes will loosen the fit the most?
a) 7.76mm, 8.0mm b) 7.69mm, 7.8mm
c) 7.63mm, 7.6mm d) 7.71mm, 7.3mm

A

b) 7.69mm, 7.8mm Higher the mm, flatter the curve;
lower the mm, steeper the curve

143
Q

Rigid gas permeable lens edge thickness should be between ___mm and ___ mm.

A

0.08-0.12

144
Q

Which of the following is NOT an advantage of rigid gas permeable lenses over soft lenses?
a) longer lens life b) better initial comfort
c) better optical quality d) fewer adverse effects

A

Better initial comfort

145
Q

The tear lens formed behind a rigid contact lens corrects which type of astigmatism?

A

Corneal

NCLE Prep (26 decks)

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