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Contact lenses year 3 > Contact lens surface changes > Flashcards

Contact lens surface changes Flashcards

1
Q

list 5 contact lens surface changes associated with RGP lenses

A
  • Lens debris
  • Lens drying
  • Poor wetting
  • Lens deposits
    • Lipids
    • Proteins
  • Lens damage:
    • Scratches
    • Crazing
    • Chips
    • Manufacturing issues
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2
Q

what are the 2 types of lens deposits associated with RGP lenses

A
  • lipids

- proteins

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3
Q

what are the 4 types of lens damage associated with RGP lenses

A
  • Scratches
  • Crazing
  • Chips
  • Manufacturing issues
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4
Q

what 5 contact lens surface changes are associated with SCL

A
  • Dehydration
  • Lens deposits
    • Lipids
    • Protein deposits
    • Calcium
    • Jelly bumps
    • Fungal
  • Rust spots
  • Lens damage
  • Lens discolouration
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5
Q

what are the 5 types of lens deposits associated with soft contact lenses

A
  • Lipids
  • Protein deposits
  • Calcium
  • Jelly bumps
  • Fungal
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6
Q

what are the 3 places lens debris on a RGP come from

A
  • biological
  • microbiological
  • environmental
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7
Q

name examples of biological lens debris found on RGP lenses

A
  • tear film/bits in tears

- skin cells

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8
Q

name examples of microbiological debris found on RGP lenses and the cause of this

A
  • bacteria
  • fungi
  • viruses

from not cleaning the lenses well enough or not washing hands before handling lenses

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9
Q

name examples of environmental debris found on RGP lenses

A
  • make up

- aerosols

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10
Q

which 2 locations can lens debris be found on a RGP lens

A
  • central
    or
  • edge
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11
Q

if lens debris on a RGP lens is found centrally, what can this indicate

A

that something has just happened recently and has attached itself on the front surface of the lens

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12
Q

if lens debris on a RGP lens is found around the edge, what can this indicate

A

the px is cleaning the lens in the middle, but not along the edge, causing a build up of debris around the edge of the lens

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13
Q

what can you do in practice to pick up on lens debris on a RGP lens and what will be your management

A
  • do a flourescein staining check as it will attach to the lens debris
  • if this occurs, just replace the RGP lens
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14
Q

what can happen to the RGP lens if too much debris is found on its surface

A

it can weigh down the lens

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15
Q

what may mask lens drying on a RGP lens

A

rapid blinking

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16
Q

what may a patient not report with RGP lens drying

A

any symptoms
as they will just blink more rapidly without realising
they may just say their vision isn’t very clear

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17
Q

how will you assess lens drying of an RGP on the slit lamp

A
  • use white light specular reflection of the tear film/front surface of cornea
  • hold the lids apart and look at the surface changes because then the patient doesn’t have to blink and so the windscreen wiper effect won’t occur and replenish the front surface of the lens i.e. the tear film
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18
Q

for what 4 reasons can poor wetting of an RGP lens be caused by

A
  • if the lens is too old, it might not wet
  • a build up of deposits: can hinder its wetting
  • poor tear film quality
  • MGD
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19
Q

what does the pre lens tear film break up time need to be higher than in order to prevent poor wetting of an RGP lens

A

the inter-palpebral blink rate

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20
Q

what is a symptom of poor wetting of an RGP lens

A

reduced lens tolerance/wear times

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21
Q

what does the action of treating poor wetting of an RGP lens depend on

A

the aetiology

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22
Q

list 3 actions that can be done for a poor RGP lens wetting

A
  • Review material/cleaning/care
    regimen
  • Rewetting drops
  • Replace lens?
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23
Q

which type of cleaning solution can be used to improve the wettability of an RGP lens and why

A

cleaning solutions such as boston advance, as it has friction enhancers that can rub off most of the deposits

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24
Q

what affects the type of deposition found on a lens and explain how

A
  • the lens material
  • each lens type has its own electrical charge, or it can be neutral
  • this depends on the material and the grouping of between 1-4
  • this means it attracts different types of deposits
  • ionic materials which are mostly -ve charged attract +ve charged deposits e.g. lysozyme
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25
Q

which type of RGP cleaner is designed to repel lens deposits

A

surfactant cleaner

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26
Q

what is the appearance of lipid RGP lens deposits

A
  • colour fringes

- glossy appearance which is greasy and shiny

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27
Q

what 3 actions can you take on an RGP lens that has lipid deposits

A
  • change to an alcohol based cleaner as this dissolves the deposits
  • change the lens material to one that attracts less lipid deposits
  • make sure the patient is cleaning the lens properly, so review their care regime
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28
Q

where does the lipid deposits on RGP lenses come from and which type of slit lamp technique allows you to detect these deposits

A
  • they come from the meibomian glands

- use specular reflection to detect

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29
Q

what is the appearance of protein RGP lens deposits

A
  • matt
  • opaque/white
  • diffuse film
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30
Q

what may be affected with protein deposits on RGP lenses

A

VA

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31
Q

what can protein deposits on RGP lenses lead to

A

induced papillary conjunctivitis

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32
Q

what 4 actions can you take on RGP protein lens deposits

A
  • Use separate cleaner,
  • Maybe protein removal tablets
  • Switch to fluropolymers or daily lenses
  • see how the patient cleans the lenses and if it still doesn’t come off then may need to switch to the Boston Advance cleaner
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33
Q

name three types of protein deposits found on RGP lenses

A
  • lysozyme
  • albumin
  • globulin
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34
Q

which type of protein deposit makes up 40% go tears

A

lysozymes

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35
Q

how do you pick up on scratches on a RGP lens

A

by viewing it on the eye with the white light on the slit lamp

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36
Q

what do you need to observe when assessing scratches on an RGP lens

A

is it one or both lenses scratched

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37
Q

what is the severity range of scratches on RGP lenses

A

mild to deep

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38
Q

what can deep scratches in RGP lenses cause potential for

A
  • microbes to accumulate

- infection

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39
Q

what can be indicated if one RGP lens is scratched

A

the px may have just dropped the lens

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40
Q

what can be indicated if both RGP lenses are scratched

A

it could be down to the handling of the lens which can be found out in history and symptoms

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41
Q

which type of RGP lenses does surface crazing occur in

A

usually with softer materials

42
Q

what can cause an RGP lens to have surface crazing

A

handling and flexure which can cause a break down of material

43
Q

what are the 2 actions can you take on RGP lens crazing

A
  • replace with different material i.e. firmer

- watch how the patient puts their lenses in and re-educate if need be

44
Q

what symptom will a patient with surface crazing on their RGP lens have and why

A

they can’t see well through their lenses as light will be reflecting everywhere

45
Q

how will you check for chips on RGP lenses

A

by checking all edges of the lens

46
Q

where can chips on an RGP lens be found

A

front of lens or back of lens

47
Q

what will happen if the chip is on the back of the RGP lens

A

the chipped RGP will rub on the cornea and abrade it, therefore the px will feel this and will be more vulnerable to breaks in the eye

48
Q

what will happen if the chip is on the front of the RGP lens

A

the patient won’t notice it and the eye is less vulnerable to breaks

49
Q

what can be the cause of chips on a RGP lens

A

handling
this can happen when the patient puts the lens in the edge of the case, so they therefore should switch to a barrel type of cases to avoid chipping

50
Q

what action is required if chips are found on an RGP lens

A

replace the lens

51
Q

how will you check for chips on a lens whilst in the patient’s eye

A
  • check with white light on the slit lamp

- once the lens is taken out, check for staining with flourescein

52
Q

what is the sign of a manufacturing issue of the RGP lens

A

there will be a steaming effect

53
Q

what 2 things can a manufacturing issue of a RGP lens be due to

A
  • heat
    or
  • a solvent
54
Q

what is done to new RGP lenses before given to the patient to avoid manufacturing issue

A

New lenses soaked for at
least 24 hours prior to
collection and parameters
verified

55
Q

what action needs to be taken with RGP lenses that have a manufacturing issue

A

replace the lens

56
Q

what will be the signs of dehydration on a SCL

A
  • always usually inferior

- might see SMILE stain on the cornea if dehydration is excessive

57
Q

what is the cause of dehydration related staining on a SCL

A

the blink pattern being incomplete, a lack of blinking

58
Q

what 3 actions can be taken for patients who have dehydration of their SCL

A 
- Rehydration-break from
lens wear, put lenses
back in case
- Change material
- Blink!
59
Q

which type of SCLs is lipid deposits associated with

A

FDA group 2 and silicone hydrogel lenses

60
Q

what are the three causes of lipid deposits on SCLs

A
  • tear lipids
  • cosmetics
  • MGD?
61
Q

what are the 2 signs/symptoms of lipid deposits on SCLs

A
  • smeary vision

- colour fringes

62
Q

what can happen to toric soft lenses which has lipid deposits on them and why

A
  • they can destabilise

- it weighs the lens down and rotates it

63
Q

what 4 actions can be taken on lipid deposits on SCLs

A
  • Review care routine
  • Increase lens replacement frequency (if they’re monthlies, switch to dailies)
  • Change material
  • Treat any MGD
64
Q

which type of SCLs is protein deposits more common in

A

FDA group 4

65
Q

where to the protein deposits on SCLs come from

A

from the tear proteins

66
Q

what is the appearance of protein deposits found on SCLs

A

Film/sheet or can be deposits

67
Q

what can denatured proteins on SCLs lead to

A

palpebral conjunctival problems

68
Q

what symptom can a patient with protein deposits on their SCL have

A

increased lens awareness

69
Q

what 3 actions can be taken for protein deposits on SCLs

A
  • Review care routine: rub and rinse
  • Increase lens replacement
    frequency (if wearing monthlies, make sure they’re changing their lenses every 30 days)
  • Change material
70
Q

which SCL deposit is easy to pick up on

A

jelly bumps

71
Q

what are jelly bumps found on SCLs

A

Focal, gelatinous lumps

72
Q

what 3 things are jelly bumps found on SCLs made up of

A

Mucous, lipid protein and calcium build up

73
Q

which SCLs is jelly bumps common in

A

FDA group 2 lenses

74
Q

what can the symptoms of jelly bumps found on SCLs range from and wha does this depend on

A
  • no discomfort to moderate discomfort

- depends on the size and amount of the deposits

75
Q

what 3 actions an be taken on jelly bumps found on SCLs

A
  • Review care routine
  • Increase lens replacement
    frequency (switch to dailies)
  • Change material-to LWC
76
Q

which type of SCL deposit is rare

A

fungal

77
Q

what causes fungal deposits on SCLs

A
  • Contamination of lens by fungus

- Areas of growth over lens

78
Q

what 2 things is fungal deposits on SCLs associated with

A
  • intermittent wearers and long-term lens storage
    e. g. someone who doesn’t wear lenses as much so the fungus can grow on the lens whilst then and did not clean them in-between
  • poor hygiene
79
Q

what 4 actions is required for fungal deposits on SCLs

A
  • Need to replace lens
  • Review hygiene
  • Care regimen
  • Dailies may be better (as fungus cannot grow on them)
80
Q

what are rust spots in SCLs

A

a metallic particle found on the SCL

81
Q

when will a patient not notice a rust spot on their SCL

A

if its on the front surface

82
Q

when will a patient notice a rust spot on their SCL

A

if its on the back surface

83
Q

where can rust spots found on SCLs come from

A

the atmosphere

84
Q

what acton is required if a rust spot is found on a SCL

A

replace the lens

85
Q

what will you do as precaution when detecting a rust spot

A

take the lens out and do a staining check to check that no other foreign body is in the eye and also evert the eyelid and check

86
Q

what 3 things can be the cause of lens damage of a SCL

A
  • Poor handling e.g. long nails
  • Lens trapped in case
  • New wearers?
87
Q

what can be a sign on lens damage of a SCL

A

may have staining

88
Q

name 2 examples of types of lens damage of SCLs

A
  • lens splitting

- chipped edge

89
Q

what 2 actions can be taken for lens damage of a SCL

A
  • Replace lens
  • Review handling of
    lens, storage, I and R
90
Q

what 3 colours can a SCL discolour to

A
  • brown
  • pink
  • white
91
Q

how will you investigate SCL discolouration

A

off the eye

92
Q

list 5 possible causes of SCL discolouration

A 
- Nicotine, other fumes,
sprays
- Hormones
- Reaction with tears
- Topical medications
- Ageing of lens (don't change lens when supposed to)
93
Q

what will you recommend for someone who has lens discolouration due to nicotine from smoking

A

stick to daily lenses

94
Q

what is a common problem of silicone hydrogel SCLs

A

lipid deposits

produces greasy smeary vision

95
Q

what 4 actions can be taken for silicone hydrogel lenses that has lipid deposits

A
  • Change lens
  • Review cleaning
  • Changing lens modality may help (change more frequently)
  • May need to refit with different material
96
Q

how are lipid on silicone hydrogel lenses prevented

A

there is now a coating on silicone hydrogel lenses to prevent this

97
Q

when can makeup on a lens be an issue

A

particularly if lens is not a daily disposable

98
Q

what can makeup on a lens cause and in particular which type of make up

A

it can cause infections whereby the source comes from mascara which is not replaced regularly

99
Q

what 2 things can you do to prevent makeup on a lens

A
  • Re-educate patient

- Advise, lenses first, make up after

100
Q

what must a px do if they get an infection due to their mascara

A

they must throw it and any other eye makeup used on the eye away in the bin

101
Q

lens conditions may be….

A

graded

102
Q

name 2 examples of grading systems used for and associated with contact lens

A
  • Contact lens opacity grading system (CLOGS)

- The RUDKO/modified RUDKO scale

Contact lenses year 3 (15 decks)

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