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Sam's Club Optical Test > ABO TEST > Flashcards

ABO TEST Flashcards

0
Q

The fibrous tunic is comprised of the:

A

sclera and cornea

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1
Q

The extra-ocular muscles are inserted into the sclera and serve to rotate the eye in all possible directions. There are of these muscles.

A

six

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2
Q

Fusion occurs:

A

in the brain

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3
Q

The aqueous fluid is continually being manufactured by:

A

the ciliary body

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4
Q

The ability of the eye to bring objects of varying distances to focus on the retina is known as:

A

accommodation

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5
Q

When accommodation is at rest, rays of light from a distant source come to focus in front ofthe retina. This condition is known as:

A

myopia

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6
Q

When accommodation is at rest, rays of light from a distant source come to focus behind the retina. This condition is known as:

A

hyperopia

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7
Q

Impulses are carried from the retina to the brain along the:

A

optic nerve

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8
Q

That area ofthe retina capable of perceiving the greatest amount of detail is:

A

fovea centralis

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9
Q

The average cornea has a refractive power of approximately:

A

43 diopters

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10
Q

That layer ofthe cornea which is highly regenerative is:

A

the epithelium

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11
Q

Night vision is chiefly a function of the:

A

rods

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12
Q

A tendency of the visual axis to deviate inward while the eyes are in a position of rest is known as:

A

esophoria

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13
Q

A “farsighted” eye is one that is:

A

hyperopic

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14
Q

The term used to indicate “double visio

A

diplopia

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15
Q

The condition in which the ability to accommodate for near vision becomes inadequate because of loss of elasticity of the crystalline lens is called:

A

presbyopia

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16
Q

When there is a loss of vision without any apparent disease ofthe eye it is known as:

A

amblyopia

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17
Q

A refractive error in which the rays of light do not come to a single point of focus is called:

A

astigmatism

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18
Q

The condition in which the crystalline lens of the eye gradually loses its transparancy with consequent loss of visual acuity is known as:

A

cataract

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19
Q

An ocular disease having as its primary characteristic a sustained increase in intraocular pressure.

A

glaucoma

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20
Q

The space between the cornea and iris that is filled with aqueous fluid

A

anterior chamber

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21
Q

A tendency of one eye to deviate upward is:

A

hyperphoria

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22
Q

The photosensitive receptors of the retina which are responsible for sharp visual acuity and color perception are the:

A

cones

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23
Q

The layer ofthe cornea which comprises ninety percent of its thickness is:

A

the stroma

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24
Q

A condition in which the refractive error of one eye significantly differs from that of the other and where both eyes have the same sign (i.e. both eyes are myopic or hyperopic) is known as:

A

anisometropia

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25
Q

The refractive error which results in two points of focus falling behind the retina is:

A

compound hyperopic astigmatism

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26
Q

The refractive condition caused by a damaged cornea so that rays of light come to many focal points on the retina is known as:

A

irregular astigmatism

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27
Q

The transparent, colorless mass of soft, gelatinous material which fills the eyeball behind the lens is the:

A

vitreous humor

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28
Q

The index of refraction of the crystalline lens is:

A

1.42

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29
Q

The cornea has an index of refraction of:

A

1.37

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30
Q

The index of refraction is lowest in:

A

air

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31
Q

When parallel rays of light Penter a prism, the light is deviated:

A

toward the base

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32
Q

One meter is equal to:

A

39.37 inches

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33
Q

Two meters equal centimeters.

A

200

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34
Q

The index of refraction of any given transparent material can be determined by:

A

dividing the speed of light in air by the speed of light in the material

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35
Q

The speed of light in air is approximately:

A

186,000 miles per second

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36
Q

When the direction of light is deviated in the course of passing from one transparent medium to another it is known as

A

refraction

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37
Q

Light travels through a certain transparent medium at the rate of approximately 109,412 miles per second. The index of refraction of that medium is:

A

1.70

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38
Q

The theory describes light as traveling through space in minute bursts of energy.

A

corpuscular

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39
Q

The focal length of a+ 1.00 diopter lens is:

A

+ 100 cm

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40
Q

If a converging lens has a focal length of +2 meters, its power is:

A

+ 0.50 diopters

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41
Q

The range of wavelengths which are perceived as visible light can vary with the individual, it is generally understood to lie between:

A

390 and 750 nanometers

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42
Q

If a prism can displace an image one centimeter at a distance of one meter, it is said to have a power of:

A

1 prism diopter

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43
Q

The distance between the crests of two waves is called the:

A

wavelength

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44
Q

The focal length of a - 5. 00 diopter lens is:

A
  • 20 cm
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45
Q

Decentering a plus lens upward will result in:

A

base up prism

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46
Q

Prentice’s Rule states that the amount of induced prism is equal to:

A

power of the lens times the decentration in millimeters + 10 Question 18

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47
Q

Prentice’s Rule states that the amount of induced prism is equal to:

A

power of the lens times the decentration in millimeters +10

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48
Q

Rx : - 2.00 D OU with a PD of 63 mm. centers set 66 mm apart. How much total prism was induced and in which direction is the base?

A

0.6 prism diopters base in

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49
Q

Rx: = + 4.00 sph OU with a PD of 59 mm. During final inspection it was determined that the optical centers were positioned 4 mm too wide. How much prism was induced in each eye and in which direction is the base?

A

0.8 prism diopters base out

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50
Q

A diverging lens produces a ___ image.

A

virtual

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51
Q

Rays emanating from a point source of light are said to be:

A

diverging

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52
Q

To determine the power of a thin lens in air, it is necessary to consider:

A

front curve, back curve and index of refraction

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53
Q

A standard lens measure is calibrated for an index of refraction of

A

1.530

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54
Q

A+ 1.75 diopter lens fabricated with a +6.00 base curve will require a back curve of:

A
  • 4.25
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55
Q

Toric transposition is used to determine:

A

lens power in the principal meridians

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56
Q

A patient presents you with an Rx + 2.75- 1.00 x 180 OU. The refractive anomaly indicated by this Rx is:

A

compound hyperopic astigmatism

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57
Q

Corrected curve lenses are designed to:

A

increase the useful area of the lens

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58
Q

The following lenses are all made with the same radius of curvature on the front surface. Which of these materials will yield the greatest front surface power?

A

flint glass

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59
Q

Question 8 8. Rx: OD + 2.50-0.50 x 180 OS +2.50 sph PD = 67. Final inspection found the optical centers 63 mm apart. How much total prism will this produce, and in which direction is the base?

A

1.0 prism diopters base in

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60
Q

If the Rx -3.00 + 0.50 x 90 is decentered 2mm too much, how much prism will be created, and in which direction is the base?

A

0.50 prism diopters base out

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61
Q

R x: +2.00- 4.00 X 45 How much prism will be created if the optical center of this lens is received 5 mm too wide?

A

none

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62
Q

As a corrected curve lens increases in minus power, the base curve tends to become gradually:

A

flatter

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63
Q

As the radius of curvature of a spherical surface increases in length, its curve becomes gradually:

A

flatter

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64
Q

As a corrected curve lens increases in plus power, the base curve tends to become gradually

A

steeper

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65
Q

As the radius of curvature of a spherical surface decreases in length, its curve becomes gradually:

A

steeper

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66
Q

Rx: Plano- 2.00 x 180. Which of the following refractive conditions is this lens designed to correct?

A

simple myopic astigmatism

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67
Q

If a patient is having difficulty handling their new soft, disposable contact lenses, what can a fitter do to make practice and learning easier?

A

Change to a lower water contact lens for the initial training

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68
Q

Which of these traits is not a benefit of hydrogel lenses?

A

Less surface deposits

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69
Q

Silicone hydrogel lenses have been approved by the FDA for up to 30 days of wear. This is considered __________.

A

Continuous wear

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70
Q

What type of allergic reactions are associated with the use of silicone hydrogel lenses?

A

Red and itchy eyes

Discomfort

Dryness

A patient can experience any of the above symptoms with silicone hydrogel lenses

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71
Q

Which of the following will not affect the safe handling of contact lenses?

A

Room humidifiers

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72
Q

What will help to relieve a temporary dry feeling when wearing contact lenses?

A

Frequent blinking

Remove the lenses and soak them

Use of physician approved eye

Any of the above can be effective

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73
Q

Tear exchange in a gas permeable lens is critical to an eye receiving adequate oxygen. Which procedure will increase tear exchange in a GP lens?

A

Decrease the optic zone

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74
Q

What is the definition of the edge apex?

A

The junction between the anterior and posterior zones

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75
Q

What is not correct regarding the cornea?

A

It is larger vertically than horizontally

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76
Q

All human tissues need replenishment of nutrition. How does the cornea receive nutrition?

A

From the tears, the aqueous and the limbal vessels

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77
Q

List the layers of the cornea from inside to out:

A

Endothelium, Descemet’s Membrane, Stroma, Bowman’s layer, epithelium

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78
Q

What is the Schirmer-2 test?

A

Is a test performed with special filter paper but no anesthetic

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79
Q

This systemic disease can cause large changes in refractive power when not controlled:

A

Diabetes

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80
Q

A significantly different refractive power between the right eye and the left eye is a condition is known as:

A

Anisometropia

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81
Q

Scleral contacts are ___________________________?

A

Designed to cover the cornea and approximately 1.00 mm of the sclera

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82
Q

What are the alternate names for the choroid?

A

Choroid coat and choroidea

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83
Q

What anatomical feature located in the posterior chamber produces aqueous humor?

A

The ciliary processes

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84
Q

How can contact lenses contribute to the development of keratitis?

A

Poor hygiene in the care of the lenses

Improper storage and use of cleaning solutions

Contact lenses being worn improperly

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85
Q

Cataracts and vitreous degeneration can cause _____________________?

A

Opacities of the media

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86
Q

When using a keratometer, the mires distort after a small amount of time. What does the contact lens fitter do?

A

Ask the patient to blink

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87
Q

After adding a supplemental +1.25 trial lens to a keratometer, you obtain a K reading of 52.00 @ 180/ 53.50 @ 90. What is the approximate corrected K reading?

A

61.00 @ 180 / 62.50 @ 90

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88
Q

A parallel fit of a contact lens can be referred to as:

A

Fitted on K

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89
Q

K reading on patient’s OD is 43.25 @180 / 44.00 @ 090. How much corneal astigmatism exists?

A

0.75 diopter

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90
Q

The K reading on a patient’s OS is 44.75 @ 180 over 44.75 @ 90. What is his ocular condition according to this reading?

A

His left eye is myopic

91
Q

Which patient will most likely find reading more difficult when using contact lenses?

A

The myopic patient over 30 years of age

92
Q

Most patients with Irregular astigmatism experience vastly improved vision with the use of a rigid contact lens. Why is this?

A

A rigid lens can create a lacrimal lens

93
Q

Sometimes a lens prescription needs to be transposed from one form to the other. Which of the following is not a step involved in transposition?

A

Change the axis to 90◦

94
Q

What is an ideal pattern with a well fitted spherical rigid contact lens?

A

The fluorescein dye shows a balanced distribution

95
Q

A corneal stain is usually an indication of corneal insult. What type of stain indicates that the junctures of the posterior curve of a lens are faulty?

A

Arcuate staining

96
Q

Which device projects a bigger picture of a rigid contact lens in order to inspect if for gross imperfections?

A

Shadowgraph
Projector magnifier
Projector inspection device

97
Q

When using a profile analyzer, what pattern would indicate a good, smooth profile?

A

A ski shape

98
Q

Which statement is not correct regarding the lipid layer of the tear film?

A

It is the inner most layer of the tear

99
Q

What is the average blink rate?

A

Approximately every five seconds

100
Q

Complete this sentence: Any tear deficiency _______________________________

A

Is a clear contraindication to extended wear lens use

101
Q

What is the anatomical feature that forms the junction between the bulbar and palpebral conjunctivas?

A

The fornix

102
Q

Name the four layers of the eyelid

A

The skin, the Orbicularis Oculi, the orbital septum and the palpebral conjunctiva

103
Q

Bright light sends signals to the oculomotor nerve and these signals terminate on the iris sphincter muscle. These signals will __________________________________

A

Contract the iris muscle and reduce the size of the pupil **

104
Q

Which of these is not a problem or disease of the eyelid?

A

Fissure

105
Q

Eyelashes perform important functions. What are they?

A

They protect the eye from dust and debris and also signal danger

106
Q

How many corneal dystrophies affect all parts of the cornea?

A

Over twenty corneal dystrophies

107
Q

Ulcerative keratitis is a serious threat to vision. Which contact lens style is most associated with this damage?

A

Extended wear lenses

108
Q

The endothelium can undergo harmful changes. What is the term for a change in cell shape variation?

A

Polymorphism

109
Q

What ophthalmic device is used to perform a break-up time test (BUT) ?

A

Biomicroscope

110
Q

Many angles can be created with the slit lamp. Which angle is used for a sclerotic scatter view?

A

90 degress

111
Q

What is the smallest direct beam used with the slit lamp at approximately 1.00 mm?

A

Optic section

112
Q

What is not easily revealed by using retro-illumination with a biomicroscope?

A

Gross edema

113
Q

Which filters are commonly used when examining the eye with the slit lamp?

A

Wratten #12

Blue cobalt

Green

114
Q

This type of stain occurs due to bubbles beneath the lens:

A

Dimple veil

115
Q

What are some characteristics to consideration

when choosing materials needed in order for the fitter to best advise the patient.

A 
Percentage of water content
The oxygen permeability
How well the material defends against deposits
Thickness
Lens edge
Lens color/tint
Design parameters
Length of wear
Replacement intervals
116
Q

A lens with greater hydration has the benefits of:

A

soft and flexible (pliable), often making the lens more comfortable.

117
Q

What are some drawbacks for high water content contact lens ?

A

Too pliable for some patients

High water content may mean more surface deposits

shorter life.

118
Q

What are some perks in regard to low water content in comparison to high water content ?

A

Less Pliable, low water content will feel more rigid when handled

less likely to have deposits on the surface

119
Q

Soft contacts are manufactured from:

A

hydrogel material

120
Q

High water content may have a negative affect on wearer, what are those negative affects:

A

Fluctuation in vision

dryness

changes in lens parameters

Surface Deposites

121
Q

General benefits of soft contact lenses:

A

Comfort

Shorter adjustment period

Good alternative to eyewear for patient with minor corrections

Sports: excellent for athletics because soft lenses will not fall out of the eye

More comfortable in environments where conditions may cause a rigid lens to have particles logged underneath the lens

122
Q

Silicone hydrogel contact lenses are advanced soft lenses that:________

A

more oxygen to pass through the lens to the cornea than regular soft (“hydrogel”) contacts

123
Q

Benefits of silicone hydrogel lenses

A

Extended wear

Continuous wear

Increased comfort and performance

Care of extended wear lenses

124
Q

Silicone hydrogel lenses have been approved for wear at all times for up ______Days. These are FDA standards.

A

30

After 30 days, the extended wear lenses need to be taken out, properly cleaned and disinfected, and kept out of the eyes a minimum of one night. If they are disposables, they should be thrown away.

125
Q

What are most common allergic responses to silicone hydrogel lenses ?

A

The most common complaints are:

redness

discomfort

itchy eyes

greater lens awareness

dryness symptoms

126
Q

Even though Silicone Hydrogel lenses allow more oxygen to reach the surface of the eye, the added can ________ surface Wettability

A

Reduce

potentially making it harder for them to stay moist on the eye

127
Q

People with marginal dry eyes would not benefit from a __________ contact lens

A

Silicone Hydrogel Contact lens

Because of reduced wetting angle

128
Q

What kind of contact lens is a contraindication for people with Irregular Astigmatism ?

A

Soft Contact

Although fit and comfort may be good, satisfactory visual acuity may not be achieved due to an irregular corneal surface.
They need the tear film lens that RGP can offer.

129
Q

What kind of contact lenses would not be good if there is liquid or gas in the air ?

A

Soft contact Lens

the lenses will absorb them and become tainted. Some chemicals can get so built up on the lens that the lens actually turns into something toxic, with the potential to really hurt the eye.

Because of their nature, soft lenses can absorb things like chemicals, germs, oils, and other materials.

130
Q

Giant papillary conjunctivitis (GPC) is a type of conjunctivitis that is caused by wearing _____ soft contacts.

A

dirty

If a patient develops this one time, then that patient is more likely to develop it again, like an allergy.

Using disposable soft contacts sometimes help, but if the problem repeats itself, then the patient should be considered for a re-fit with rigid lens.

131
Q

Things you should not handle when dealing with soft contact lenses ?

A

Spicy Food

Lotions, cosmetic sprays and creams

Handling of spicy foods can transfer on to the patient’s contact lenses even after the washing of hands. This can cause stinging and burning.

Lotions often contain conditioner which is harder to wash of the hands. Cosmetics, sprays, and creams can be difficult to remove from fingers. If a soft lens is affected, it may need to be discarded,

132
Q

Patients who have irregularities or bumps on the sclera and/or bulbar conjunctiva may_____be able to wear soft lenses.

A

Not

If a bump is situated so that it moves the lens away from the eye, then the lens won’t receive enough hydration. Also, if the lens touches the bump during a blink, some irritation might occur. One solution could be to use a lens with smaller diameter.

133
Q

What can be done to a GP lens to increase tear exchange ?

A

Reduce the overall lens diameter
Flatten the peripheral curves
Decrease the optic zone

Basically loosening the lens

134
Q

Optical Zone

A

is the chord diameter over which the base curve extends on the posterior surface of the contact lens

135
Q

How much flatter is the peripheral curve in comparison to the base curve?

A

0.70 mm to 1.50 mm flatter than the base curve radius

136
Q

What is blending in regard to contact lenses ?

A

Blending is the treatment given to the sharp junctions created by the differences in the radii of curvature between the base curve, the secondary curve, and the peripheral curve.

137
Q

What two curves on the posterior aspect of a contact lenses are more likely to be blended ?

A

Secondary curve and the peripheral curve.

A blend is rarely required at the base curve/secondary curve junction. This is due to minimal change between the two radii.

138
Q

What are other names for the anterior optical zone radius

A

the power curve or the lenticular cap

139
Q

What is the Lens Edge designed for ?

A

The edge is designed to limit adverse lid irritation during blinking, and plays a role in keeping the posterior lens surface away from the cornea.

140
Q

The edge of a lens can be divided into 3 zones that are they ?

A

Anterior Zone

Posterior Zone

Edge Apex

The Anterior Zone is that portion of the edge in contact with the upper lid during the blink cycle. Its function is to minimize lid irritation during the blink.

The Posterior Zone is a small reverse curve placed on the posterior lens surface to flare the edge away for the cornea. Its function is to allow free movement of the lens across the cornea during the eye excursions and to permit lens removal using scissor blink technique. The posterior zone also allows the lens to be safely centered on the cornea when lens dislocation occurs.

The Edge Apex is the junction between the anterior and posterior zones. This junction must be well rounded to minimize lid awareness during the blink.

141
Q

Cornea

A

The cornea is the clear surface on the front of the eye that covers the iris and pupil. It lets light into the eye.

142
Q

What is the radius of curvature of the anterior surface of the cornea ?

A

7.7 mm

143
Q

What is the radius of curvature of back surface of the cornea ?

A

6.8 mm

144
Q

The center of thickness of the cornea is ?

A

.5mm

145
Q

The is the edge thickness of the cornea ?

A

1.0 mm

146
Q

What is the average diameter of the cornea horizontally ?

A

11.5 mm

147
Q

What is the average diameter of the cornea

vertically ?

A

11.2 mm

148
Q

What is the average dioptric power of the cornea ?

A

43.00 D or 70% of the total amount of refraction.

149
Q

What is the most powerful refractive surface of the eye ?

A

Cornea

150
Q

what is the anterior surface refractive power and the posterior surface power ?

A

Anterior: +48.8 D

Posterior: -5.8 D

151
Q

The longer the radius of curvature the _______ the lens

A

Flatter or looser the lens

152
Q

The shorter the radius of curvature the __________ the lens

A

The steeper or tighter the lens

153
Q

What is the corneal cap ?

A

is the central portion of the cornea with a constant radius of curvature AKA apical zone of the cornea

154
Q

Apical mean what ?

A

Apex or at the top

155
Q

What is the index of refraction of the cornea ?

A

1.376

156
Q

The cornea can receive nutrients from that ?

A

oxygen by the aqueous humor
tears
vascular blood vessels in the limbus.

157
Q

Where does the anterior aspect of the cornea get is oxygen from ?

A

Air diffused by tears

158
Q

Where does the posterior aspect of the cornea get its oxygen from ?

A

Aqueous Humor

159
Q

When there is not enough oxygen in the eye this is called ?

A

Hypoxia

160
Q

Epithelium makes up ____ % of the corneal thickness

A

10 %

161
Q

Cornea epithelial cells can In the first 24 hours they cells slide and migrate to cover any open area, then the epithelium will begin to generate new cells over the damaged area.

True or false ?

A

True

162
Q

Stroma comprises who much of the cornea ?

A

90%

163
Q

The stroma has ______ kind of of collagen fibers that are woven together at right angles.

A

Lamellae

164
Q

Endothelium is made up of what kinds of cells ?

A

one layer of hexagon-shaped cells; it makes up 10% of the thickness of the cornea.

165
Q

How long is a BUT (Break Up Time)

A

10-12 seconds

166
Q

What is a schemer’s Test for ?

A

evaluates aqueous tear production

It is used in the assessment of patients with signs and/or symptoms of dry eye. It can determine whether surface dryness is due to reduced tear production from the lacrimal glands as opposed to some other cause, such as blepharitis, meibomitis, or exposure.

167
Q

How do you perform a Schirmer’s test ?

A

a special filter paper is used which is 5mm wide and 35mm long in an eye that has not been anaesthetized. A normal tear output should wet at least 15 mm of filter paper in 5 minutes.

168
Q

What is the difference between Schirmer 1 and Schemer 2 test ?

A

Shirmer 1 test Has anesthetic and Shirmer 2 test does not have any anesthetic ( measures baseline plus reflex secretion)

169
Q

What is a nevus

A

a benign growth; shape is small and flat, color is pigmented (tan, brown, or skin color)

170
Q

Pinguecula

A

benign growth; shape is small, roundish, color is yellowish or yellowish brown.

171
Q

Pterygium:

A

an abnormal growth on the medial bulbar conjunctiva; shape is triangular; possibly caused from irritation from the sun. This condition may cause scarring in the cornea and eventually may cause vision impairment or vision loss.

172
Q

Subconjunctival hemorrhage:

A

this is when a blood vessel breaks under the conjunctiva; symptoms include a bright red eye that usually lasts a week to ten days and does not actually harm the eye. This can be caused by trauma, sneezing, coughing, high blood pressure, or other causes.

173
Q

Fornix

A

is between the lid and the globe, and you can see it on yourself if you pull down your bottom eyelid.

174
Q

The crystalline lens is ___ mm across and 3.5 mm thick

A

10mm across and 3.5 mm thick

175
Q

What is the total power of the eye is _____ diopters.

A

60 Diopters

Cornea supplies about 70% of that power and most of the remaining power is supplied by the crystalline lens.

176
Q

That is the Amplitude of Accommodation

A

the maximum amount that the eye’s crystalline lens can accommodate (change shape), in diopters (D).

177
Q

presbyopia is

A

A loss of the flexibility in focus is inevitable as we get older due to stiffening of the lens

178
Q

senile cataract

A

The most common type of cataract is caused by the aging of the crystalline lens

179
Q

Factors that cause cataracts

A

heredity

injury

disease

toxicity

radiation.

180
Q

What is Aniridia ?

A

is a partial or complete loss of the iris. This is a congenital disorder.

181
Q

What is Ocular albinism

A

where there is no pigment in the iris or retina.

182
Q

What is Bullous Keratopathy

A

is damage or disease in the endothelial region which results in bullae (swollen) appearing. The patient may experience sharp pain, light sensitivity, and a feeling of tearing or having foreign matter in the eyes.

183
Q

What is a keratometer for ?

A

also called the ophthalmometer, measures the curve of the cornea.

184
Q

What is Transient keratometric

A

mire distortion can be caused by pre-ocular tear film, and can be cleared up by asking the patient to blink.

185
Q

What is refraction ?

A

As light comes into different mediums, the speed slows downs and bends.

186
Q

How much prismatic effect is there with contract lenses ?

A

None

The lenses are right on the eye, so the optical center is always directly in front of the visual axis.

187
Q

Will accommodation be easier or harder for a hyperopic person ?

A

a person with hyperopia will have an easier time accommodating to close range vision than with glasses. They will have less accommodating to do.

188
Q

Will accommodation be easier or harder for a myopic person ?

A

a person with myopia will need to accommodate more with their contact lenses then with their eyeglasses.

f a person is over 30 and is also a strong myope, they might find it hard to read with contact lenses. That is because contacts in a strong myope create a need for more accommodation at the reading level. Reading glasses might become necessary along with the contacts.

189
Q

What two kinds of hyperopia are there ?

A 
Axial hyperopia (length of eye is too small)
refractive hyperopia (crystalline power is too weak)
190
Q

Contraindications for bandage lenses

A

Very dry eyes
Bad hygiene
infections are also contraindications to bandage lenses.

191
Q

What is 3 and 9 o’clock staining ?

A

seen on a patient with a rigid lens due to lack of hydration or exposure, can happen if the patient does not blink often enough,if the person is wearing the lenses too long at a time, if the edges are too thick

192
Q

What is Arcuate Staining ?

A

shaped like an arch on the edge of the lens and It happens because the blend between the junctures of the posterior curves is inferior.

193
Q

What tools can be used to evaluate the overall diameter ?

A

diameter gauges,

measuring magnifiers, or projection magnifiers

194
Q

What tools can be used to evaluate the Posterior Optical Zone Diameter?

A

measuring magnifiers or shadowgraphs

195
Q

What tools can be used to see the Peripheral Curves:

A

measuring magnifiers or shadowgraphs

196
Q

What tools can be used to see Blends ?

A

profile analyzers or fluorescent light bulbs

197
Q

what tools can be used to see Center and Edge Thickness:

A

thickness gauges

198
Q

what can be used for Checking Edges:

A

hand-held magnifier, measuring magnifier, shadowgraphs or slit lamps (be sure to include the profile, shape and apex)

199
Q

What are the 3 layers of the cornea ?

A

lipid layer

aqueous layer

mucoid layer

200
Q

Where do the oils that make up the lipid layer come from ?

A

It consists of oils that come from the meibomian and Zeis glands

201
Q

What is the main function of the lipid layer ?

A

It functions primarily to prevent rapid evaporation which would result in dry areas on the cornea and subsequent discomfort and corneal damage.

202
Q

What is the index of refraction of tears ?

A

1.3375

203
Q

How long is a BUT test ?

A

10-12 seconds .

A BUT of less than 10 seconds may contraindicate contact lens wear.

204
Q

What is dacryoadenitis

A

Inflammation of the lacrimal glands

205
Q

what is dacryosystitis

A

an inflamed lacrimal sac

206
Q

what is epiphora

A

blocked drainage system, causing tears to drain down the face

207
Q

what is keratitis sicca

A

tear deficiency, causing dry eyes and an inflamed cornea

208
Q

The conjunctiva is typically divided into three parts what are they ?

A

Palpebral or tarsal conjunctiva - lines the eyelids. It is tight over the tarsal region and less tight over the orbital region

Bulbar or ocular conjunctiva - Covers the eyeball, over the anterior sclera. It is the part that lines from the globe to the limbus, and it is tight in that area

Fornix conjunctiva - Forms the junction between the bulbar and palpebral conjunctivas. It is loose and flexible, allowing the free movement of the lids and eyeball

209
Q

What are the horizontal and vertical measurements of the palpebral fissure

A

Vertical: 10mm high.
Horizontal: 30mm across

210
Q

What is Blepharoptosis ?

A

(ptosis): this is when the upper eyelid is droopy

211
Q

What is a Chalazion ?

A

this is when the meibomian gland in the eyelid becomes inflamed and blocked, creating a bump on the lid.

212
Q

What is a Hordeolum

A

(stye) this is a swollen bump that is usually on the base of the eyelashes; an infection on a Zeis gland; common in babies
Bacteria related

213
Q

What is the Tolerance of a Contact Lens CPC or Base?

A

+/- .025mm or .12D

214
Q

What device do you use to inspect the base curve of CPC of a contact lens ?

A

Radiuscope

215
Q

What is the Tolerance of contact Lens Power ?

A

+/- .12D if it is less then 10 D

+/- .25D if it is more then 10D

216
Q

How do you check Contact lens power ?

A

Lensometer

217
Q

What is the tolerance of the Center of Thickness of a Contact Lens ?

A

+/- .02mm

218
Q

How do you check the thickness of a contact lens ?

A

Dial Gauge (aka) Thickness gauge

219
Q

How do you check the total diameter of a contact lens ?

A

Measuring Magnifier
Projector Magnifier
V channel
Slip or Slot Gauge

220
Q

What is the tolerance for Total Diameter of a contact lens ?

A

+/- .05mm

221
Q

If a soft Contact Lens Rx has less then 1.00D of Cyl what kind of lens can be fit ?

A

Sphere

222
Q

If a soft contact Lens Rx has more then 1.00D of Cly what kind of lens can be fit ?

A

Toric Lens

223
Q

When do you use a front surface toric design on a RGP Lens ?

A

When there is more then 1.00D of residual/Lenticular (difference in corneal and rx astigm) in the Rx. This makes an optical problem?

224
Q

When do you use a back surface toric or bitoric design on a RGP Lens ?

A

When the corneal astigmatism is more then 3.00 D ( fitting Problem)

225
Q

When do you do vertex compensation for a contact lens ?

A

-/+ 4.00D sphere power

226
Q

When do you use a toric design for a soft contact ?

A

When the cylinder is more then 1.00D or when the sphere is 3 x more then the cyl.

Sam's Club Optical Test (2 decks)

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