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III. Contact Lenses I > Final > Flashcards

Final Flashcards

1
Q

What is the GP fitting method in which you order the patient’s first lens based on measurements alone?

A

empirical

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2
Q

What is the GP fitting method in which you have the patient try on trial lenses to determine the best fit then order in appropriate power?

A

diagnostic

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3
Q

What are the main categories of things to evaluate with GP lens fitting?

A 
 Centration
 Lid Attached or IP*
 Central fluorescein pattern*
 Peripheral fluorescein pattern*
 Power (Over-refraction)
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4
Q

When should an over refraction be vertexed?

A

if exceeds +/-4.00

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5
Q

What is the GP wear schedule in which the lens is worn when awake only?

A

daily wear

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6
Q

What is the GP wear schedule in which the lens is worn for up to 6+ consecutive days and nights before overnight removal?

A

extended wear

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7
Q

What is the GP wear schedule in which the lens is worn for up to 20+ consecutive days and nights before overnight removal?

A

continuous wear

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8
Q

What is the neophyte follow up schedule for GP daily wear?

A 
 Baseline (fitting) examination
 Dispensing (3-10 days)
 1-2 week follow-up
 1-3 month follow-up
 6 month follow-up visit (as needed)
 Yearly examination (& re-fitting)
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9
Q

What is the neophyte follow up schedule for GP extended/continuous wear?

A 
 Monitor more closely…
 Day 1 (must be am visit)
 1-2 week
 1-3 months
 6 months
 Yearly exam
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10
Q

What is the veteran follow up schedule for GP daily wear?

A

 Dispensing (3-10 days)
 1-2 week follow-up
 3-6 month follow-up (as needed)
 Yearly exam (& re-fitting)

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11
Q

What are some things that you should definitely avoid while wearing GP CLs?

A
  1. swimming and showering

2. cosmetics that aren’t oilfree

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12
Q

What class of medical devices are CL’s?

A

class 2

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13
Q

What should be told to neophyte GP CL wears about adaptive signs and symptoms?

A
  1. expected during first few days to weeks
  2. diminishes with each day
  3. discomfort
  4. tearing, FB sensation
  5. increased blinking
  6. intermittent blurry vision
  7. redness
  8. light sensitivity
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14
Q

What is the tear fluid that is trapped between a GP lens and the front surface of the cornea called?

A

lacrimal lens

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15
Q

What is the equation to find the lacrimal lens value in an empirical fit? 1. Contact lens power in empirical fit? 2

A
  1. LL = BCR - Ks

2. CLP = SpecRx - LL

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16
Q

What is the astigmatism that remains after placing the GP CL on the eye? 1. What are the two type? 2

A
  1. residual astigmatism

2. regular and irregular

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17
Q

What is the equation for the predicted GP residual astigmatism?

A

Predicted = Total ocular astig - corneal astig = spectacle cyl - corneal cyl

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18
Q

What neutralizes corneal astigmatism in GP lenses?

A

lacrimal lens

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19
Q

What are the formaulae used for the optical cross calculation?

A
  1. LL = BCR - Ks

2. SpecRx = LL + CLP + Residual astig (or over refraction)

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20
Q

For the have versus need evaluation of GP lenses what is the need? 1. The have? 2. What does it find? 3

A
  1. spectacle cylinder measured by refraction
  2. corneal cylinder corrected by lacrimal lens
  3. residual astigmatism
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21
Q

Using the have versus need method, if the spectacle cylinder is the same axis as the corneal cylinder and greater in magnitude, will the patient need (more or less) than they have? 1. Will they be over or under corrected? 2. Will the RA axis be the same or off? 3

A
  1. more
  2. under
  3. same
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22
Q

Using the have versus need method, if the spectacle cylinder is the same axis as the corneal cylinder and lesser in magnitude, will the patient need (more or less) than they have? 1. Will they be over or under corrected? 2. Will the RA axis be the same or off? 3

A
  1. less
  2. over
  3. 90deg away from spectacle axis
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23
Q

For a WTR cornea, if the spectacle cylinder is WTR and equal to the corneal cylinder, what’s the RA? 1. If the spectacle cylinder is WTR and greater than the corneal cylinder? 2. If the spectacle cylinder is WTR and less than the corneal cylinder? 3

A
  1. 0
  2. WTR
  3. ATR
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24
Q

For a ATR cornea, if the spectacle cylinder is ATR and equal to the corneal cylinder, what’s the RA? 1. If the spectacle cylinder is ATR and greater than the corneal cylinder? 2. If the spectacle cylinder is ATR and less than the corneal cylinder? 3

A
  1. 0
  2. ATR
  3. WTR
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25
Q

What are the deposition issues involved in contacts?

A
  1. protein deposits
  2. lipid deposits
  3. surface damage
  4. caliculi, jelly bumps
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26
Q

With a non contact lens wearer, are the bacterial infections mostly gram positive or negative? 1. CL wearer? 2

A
  1. gram +

2. gram -

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27
Q

What are the four major functions of CL solutions?

A
  1. disinfect/clean (preservatives kill and inhibit)
  2. enhance surface wetability (optics and comfort)
  3. keep lens hydrated
  4. mechanical buffer between lens and cornea
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28
Q

What are the types of disinfection substances in CL solutions?

A
  1. Benzalkonium Chloride (BAK)
  2. Chlorhexidine (limited yeast/fungi, only GP)
  3. Ethylenediamine Tetraacetate (EDTA)
  4. Ployaminopropyl Biguanide (PAPB)
  5. Polyquaternium-1
  6. Benzyl Alcohol
  7. Hydrogen Peroxide
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29
Q

What are the different levels of efficacy of disinfectants (and whether it is bactericidal or bacteriostatic)?

A
  1. sterilization (bactericidal)
  2. disinfection (bactericidal and bacteriostatic)
  3. preservation (bacteriostatic)
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30
Q

What is the exposure time to kill 90% of an organism called?

A

D value

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31
Q

What is the solution type that requires rinse, rub, and soak called?

A

regimen solution

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32
Q

What is the solution type that does not require rinse, rub, and soak called?

A

disinfecting solution

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33
Q

What are detergents that solubilize debris from a lens and change the charge of the surface called?

A

surfactants

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34
Q

What are the different types of surfactants?

A
  1. Poloxamer (Pluronic F87 (AMO); Pluronic F127 (CIBA))
  2. Poloxamine (Tetronic 1304 (Alcon); Tetronic 1107 (B&L))
  3. CP-ED3A (OptiFree RepleniSH)
  4. Isopropyl Alcohol (Miraflow)
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35
Q

What is the substance whose function is to act synergistically with other agents to improve disinfection and cleaning?

A

chelating agents

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36
Q

What are examples of chelating agents?

A
  1. EDTA
  2. Citrate (OptiFree products)
  3. Hydroxyalkylphosphonate (Hydranate, B&L)
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37
Q

What are the different types of wetting agents?

A
  1. Polyvinyl alcohol (PVA)

2. Methylcellulose (Increase viscosity)

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38
Q

What is the water soluble polymer used to lubricate mucous membranes and improve comfort? 1. What are names of other lubricating agents? 2

A
  1. demulcents
  2. HPMC & Propylene Glycol (Complete
    MoisturePLUS) and Dexpant-5 (dexpanthenol & Sorbitol)
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39
Q

What is the GP solution that is the best at removing things?

A

optimum

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40
Q

What are the non-abrasive GP solutions?

A
  1. menicon progent

2. unique pH

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41
Q

Which soft CL solutions have polyquad preservatives?

A
  1. revitalens ocutec
  2. opti-free express/pure mosit/ replenish
  3. biotrue
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42
Q

Which soft CL solutions have biguanides preservatives?

A
  1. biotrue
  2. ReNu fresh, ReNu sensitive
  3. complete MPS easy rub
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43
Q

Which soft CL solutions have hydrogen peroxide preservatives?

A
  1. ClearCare

2. PeroxiClear

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44
Q

What are aspheric contact lenses good for?

A

patients who want a multifocal

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45
Q

How does a spheric GP lens align on the cornea of an aspheric cornea? 1. What does this result in? 2

A
  1. along flat meridian

2. excessive clearance in steep meridian with tear pooling there

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46
Q

What are the indications for spherical soft contact lenses?

A 
 Good tear quality and quantity
 Low astigmatism
 Athletes or others where GPs will be dislodged
 Unable to adapt to GPs
 Complications with GPs
 Motivated
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47
Q

What are the contraindications for spherical soft contact lenses?

A 
 Inflammation or Anterior Segment Disease
 Poor hygiene
 Not motivated
 Chronic allergies/antihistamine use
 Autoimmune disease/immunocompromised
 Dry eye
 Irregular astigmatism
 Radial Keratotomy
 Dry, dusty environments
 Giant Papillary Conjunctivitis (GPC) / Contact Lens Papillary Conjunctivitis
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48
Q

What are the advantages of soft CL’s?

A 
 Excellent initial comfort
 Minimal adaptation
 Part-time wear possible
 Corneal distortion minimal
 Minimal spectacle blur
 Dislocation uncommon
 Fit and dispense from inventory
 Change/enhance eye color
 Simple to fit
 Disposable/frequent replacement possible
 Therapeutic use possible
49
Q

What are the disadvantages of soft CL’s?

A 
 Reduced VA with uncorrected cyl
 Limited durability
 Poor O2 transmission with hydrogels
 Deposit formation/GPC/CLPC
 Increased risk of bacterial infection
 More difficult to verify
 Limited parameters available
50
Q

What are the main contact lens reference guides?

A
  1. Tyler’s Quarterly

2. Contact Lenses and Solutions Summary (CLASS)

51
Q

What are the soft CL diameter parameters? 1. power (BVP)? 2. Center thickness (-)? 3. Center thickness (+)? 4. Back surface? 5. Front surface? 6

A
  1. 12.0 to 16.0mm
  2. +/- 20.00D
  3. 0.03 to 0.18mm
  4. 0.20 to 0.70mm
  5. monocurve, bicurve or aspheric
  6. lenticulated
52
Q

Is the base curve K for soft CL’s steeper or flatter than GP’s? 1. What is the range? 2

A
  1. flatter

2. 8.00 to 9.20

53
Q

What does the larger overall diameter of soft CL’s lead to?

A
  1. inc stability and comfort
  2. inc sag depth, resulting in need for flatter BCRs
  3. dec tear exchange
54
Q

How do you steepen a soft CL?

A
  1. dec (in mm) BCR (inc in D)

2. inc OAD

55
Q

How do you flatten a soft CL?

A
  1. inc (in mm) BCR (dec in D)

2. dec OAD

56
Q

What are the different types of soft CL colored lens tint types?

A
  1. handling tint
  2. enhancing tint
  3. opaque tint
  4. prothetic masking tint
57
Q

What is the brand of cosmetic colored soft CL sold?

A

Acuvue Define

58
Q

What are the brands of prosthetic tint colored soft CL sold?

A
  1. Alden Optical
  2. CIBA Special Eyes program
  3. CooperVision prosthetic lenses
  4. Adventure in Colors
  5. Crystal Reflections
59
Q

What are the ideal factors for a soft CL?

A

 Centered & conformed to eye.
 Move adequately with the blink.
 Cover the cornea in all positions of gaze

60
Q

What are the fitting procedures for soft CL’s?

A

 Step 1: Prefitting Exam
 Step 2: Select OAD
 Step 3: Select BC
 Step 4: Select power
 Step 5: Select trial lens (specific material)
 Step 6: Assess fitting characteristics (Coverage, Centration, Movement)

61
Q

What is the typical OAD range if the corneal diameter is less than 10.0mm? 1. For 10.5 to 11.5mm (normal)? 2. Over 11.5mm? 3

A
  1. 13.0 to 13.7mm
  2. 13.8 to 14.2mm
  3. 14.3 to 16.0mm
62
Q

What is the minimum amount of time for the settling period for soft CL?

A

10 min

63
Q

What is the acceptable amount of movement in mm for a soft CL in primary gaze? 1. Upgaze or sidegaze? 2. What are the clinical terms to describe the movement? 3

A
  1. 0.30 to 1.00mm
  2. up to 1.5mm
  3. adequate, minimal, excessive
64
Q

What does movement of a soft CL depend on?

A
  1. rigidity/flexibility
  2. water content
  3. sagittal depth
65
Q

How does increasing the sagittal depth of a soft CL impact the movement of the lens?

A

decrease

66
Q

What are the ways to increase the sagittal depth of a soft CL?

A
  1. Increase OAD & hold BCR constant
  2. Steepen BCR & hold OAD constant
  3. Increase OAD & steepen BCR
67
Q

What are the benefits of daily disposable CL’s?

A
  1. lowest rate of overall complications

2. lowest level deposition

68
Q

What are the factors to consider when choosing which soft CL’s to use for a patient?

A
  1. wearing schedule
  2. oxygen needs
  3. replacement schedule
69
Q

What are the monthly disposable silicone soft CLs?

A 
 Air Optix Night & Day Aqua
 Air Optix Aqua (4 weeks)
 Purevision2 HD
 Purevision
 Biofinity
 B+L Ultra
 Acuvue Vita
70
Q

What are the 2 week disposable silicone soft CLs?

A

 Avaira (UV)

 Acuvue Oasys (UV, therapeutic)

71
Q

What are the daily disposable silicone soft CLs?

A 
 1 Day Acuvue Trueye (UV)
 Acuvue Oasys 1 Day (UV)
 Clariti (UV)
 Dailies Total 1 (Water gradient)
 MyDay (UV)
72
Q

What are the monthly disposable hydrogel soft CLs?

A

Proclear (indicated for dry eye)

73
Q

What are the daily disposable hydrogel soft CLs?

A 
 Soflens Daily
 Dailies Aqua Comfort Plus
 Proclear 1-Day
 Acuvue 1-Day Moist
 B+L BIOTRUE One Day
74
Q

What are the strategies to increase Dk in soft CL’s?

A
  1. inc water content (first)

2. inc silicone content

75
Q

What is the equation for %water content? 1. What is the desired value? 2

A
  1. (wet weight - dry weight)/wet weight

2. over 50%

76
Q

What is the percent water content of hydrogel soft CL’s? 1. Does the Dk increase or decrease when the water content is increased? 2

A
  1. 25 to 80%

2. increase

77
Q

What is the percent water content of silicone soft CL’s? 1. Does the Dk increase or decrease when the water content is increased? 2

A
  1. lower water content

2. decrease

78
Q

What are the exceptions when it comes to water content in soft CL’s?

A
  1. BIOTRUE One Day

2. Dailies Total 1

79
Q

What are the characteristics of high water content (over 50%) non silicone soft CL’s?

A 
 Increased Dk
 Increased thickness
 Less Stable(dimensionally): Difficult care
 More flexible
 Increased dehydration
 More deposition
 More difficult care
80
Q

What are the characteristics of low water content (under 50%) non silicone soft CL’s?

A 
 Low Dk
 Decreased thickness
 More stable: Easier care
 More rigid
 Less dehydration
 Less deposition
 Less difficult care
81
Q

What are the advantages of silicone hydrogels?

A

dec hypoxic complications

82
Q

What are the disadvantages of silicone hydrogels?

A

inc mechanical complications

83
Q

What are the 5 material groups of soft CL’s?

A
  1. Group 1 = Low Water (less than 50%), Non-Ionic
  2. Group 2 = high water (more than 50%), non-ionic
  3. Group 3 = Low Water (less than 50%), Ionic
  4. Group 4 = high water (more than 50%), ionic
  5. Group 5 = Silicone Hydrogels
84
Q

What is the deposition type on group IV lenses? 1. Group II lenses? 2

A
  1. 17x more protein

2. 2x more lipid

85
Q

What determines the modulus of a soft CL?

A

polymer chemistry

86
Q

What does doubling the thickness from 0.035 to 0.07mm increase the rigidity by?

A

8x

87
Q

What are used on silicone hydrogels to improve wettability?

A
  1. plasma

2. internal wetting agents

88
Q

Which monomer making up soft CL’s is similar to the lipid bilayer of cells and binds to water well?

A

phosphorylcholine

89
Q

What was the first soft lens material? 1. What were the advantages? 2. Disadvantages? 3

A
  1. polyHEMA
  2. Cheap, Easily machinable, Long life, Dimensionally stable
  3. Low Dk: ↑ edema, vascularization, etc and Reduced thickness = Poor handling
90
Q

What are the disadvantages of standard hydrogel materials compared to original?

A
  1. dehydration
  2. hypoxia complications
  3. protein deposition
91
Q

What are the advantages of silicone hydrogel materials?

A
  1. improve Dk
  2. reduced hypoxic complications
  3. less dehydration
92
Q

What are the disadvantages of silicone hydrogel materials?

A
  1. more mechanical complications

2. still deposition

93
Q

What are the CL for pediatric aphakia?

A

silicone elastomers

94
Q

What were the first FDA soft CL’s?

A

spin cast

95
Q

What are the two modern methods of manufacturing soft CL’s?

A
  1. molding (most common)

2. lathe cut and polish (specialty)

96
Q

What is the advantage of lathe cutting and polishing soft CLs? 1. Disadvantages? 2

A
  1. any design possible

2. high cost, less reproducibility, lower volume

97
Q

What are the two types of molding of soft CLs?

A
  1. cast molding

2. injection molding

98
Q

What are the advantages of molding soft CLs?

A

 high volume
 low cost per lens (after initial large investment)
 highly reproducible

99
Q

What are the disadvantages of molding soft CLs?

A

 limited parameters

 high cost to get started

100
Q

What is the extra step involved in manufacturing silicone lenses?

A

molded then surface treated with plasma

101
Q

What is the illumination type that occurs when the refractive index is higher than surrounding tissue? 1. Where is the reflection compared to light shining on it? 2

A
  1. reversed illumination

2. opposite to the light

102
Q

What is the illumination type that occurs when the refractive index is lower than surrounding tissue? 1. Where is the reflection compared to light shining on it? 2

A
  1. non reversed illumination

2. same side to light

103
Q

What are the non-CL lid issues?

A

 Internal/External Hordeolum

 Anterior Blepharitis

104
Q

What type of lens can create CL-induced ptosis?

A

GP lens

105
Q

What are conjunctival folds parallel to lower lid margin from agin, inflammation and mechanical forces called?

A

LIPCOF

106
Q

If a patient resents with pinguecula you think are CL related what should be done?

A
  1. smaller diameter lens

2. lower modulus

107
Q

What is the staph-related limbal disorder associated with blepharitis? 1. What is the treatment? 2

A
  1. phlyctenulosis

2. discontinue CL wear

108
Q

What portion of the limbus is affected by VLK? 1. What causes it? 2. What is Tx? 3

A
  1. 3 and 9 o’clock
  2. GP’s (edge lift problem)
  3. grades 3 and 4 need pharm tx
109
Q

What are the causes of limbal SLK if related to CLs?

A
  1. mechanical
  2. deposits
  3. hypoxia
  4. thimerosal
110
Q

What are the corneal staining types that can come from GP’s?

A
  1. 3 and 9 staining
  2. dimple veiling
  3. foreign body tracks
111
Q

What are the corneal staining types that can come from soft CL’s?

A
  1. SEAL
  2. SMILE
  3. epithelial plugs
112
Q

What are the intraepithelial lesions that have central negative staining and typically white eyes that is not CL related?

A

Thygeson’s SPK

113
Q

What are the types of lenses that can create corneal stroma wrinkling?

A

highly elastic lenses (group 4)

114
Q

What are the signs of CL Associated Infiltrative Keratitis (CLAIK)?

A

 Mild to moderate discomfort
 Mild diffuse injection rather than sectoral
 Bilateral
 Scattered grainy infiltrates (Gram − ?)
 Silicone hydrogel material
 Mild diffuse stromal edema

115
Q

What did the Manchester Keratitis Study show?

A
  1. No relationship between location of CIE and severity
  2. 50% of severe keratitis cases were culture negative
  3. extended wear increases incidence of CIEs
116
Q

What are the criteria that need to be met to be a corneal infiltrate event (CIE)?

A
  1. Wearing Cl’s
  2. Patient presents with discomfort that is not resolving or becoming worse
  3. CIE is in the eye(s) that is uncomfrotable
117
Q

What are the signs of corneal exhaustion syndrome?

A 
 CL intolerance
 Edema
 Polymegathism
 Discomfort
 Due to low Dk lenses
118
Q

What are good practitioner factors to avoid CL complications?

A 
 Make sure the contact lens fits well
 Look for dry eye, lid issues, other ocular disorders BEFORE you fit
 Prescribe an APPROVED wearing schedule
 Prescribe a care/cleaning regimen
 Educate at every visit
119
Q

What are important tips regarding CL cases to give to the patient?

A
  1. replace every 3 to 6 months
  2. wipe with tissue
  3. store caps upside down

III. Contact Lenses I (2 decks)

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