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
2
Q
what are the 2 types of lens deposits associated with RGP lenses
A
- lipids
- proteins
3
Q
what are the 4 types of lens damage associated with RGP lenses
A
- Scratches
- Crazing
- Chips
- Manufacturing issues
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
5
Q
what are the 5 types of lens deposits associated with soft contact lenses
A
- Lipids
- Protein deposits
- Calcium
- Jelly bumps
- Fungal
6
Q
what are the 3 places lens debris on a RGP come from
A
- biological
- microbiological
- environmental
7
Q
name examples of biological lens debris found on RGP lenses
A
- tear film/bits in tears
- skin cells
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
9
Q
name examples of environmental debris found on RGP lenses
A
- make up
- aerosols
10
Q
which 2 locations can lens debris be found on a RGP lens
A
- central
or - edge
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
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
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
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
15
Q
what may mask lens drying on a RGP lens
A
rapid blinking
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
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
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
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
20
Q
what is a symptom of poor wetting of an RGP lens
A
reduced lens tolerance/wear times
21
Q
what does the action of treating poor wetting of an RGP lens depend on
A
the aetiology
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?
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
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
25
which type of RGP cleaner is designed to repel lens deposits
surfactant cleaner
26
what is the appearance of lipid RGP lens deposits
- colour fringes
| - glossy appearance which is greasy and shiny
27
what 3 actions can you take on an RGP lens that has lipid deposits
- 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
28
where does the lipid deposits on RGP lenses come from and which type of slit lamp technique allows you to detect these deposits
- they come from the meibomian glands
| - use specular reflection to detect
29
what is the appearance of protein RGP lens deposits
- matt
- opaque/white
- diffuse film
30
what may be affected with protein deposits on RGP lenses
VA
31
what can protein deposits on RGP lenses lead to
induced papillary conjunctivitis
32
what 4 actions can you take on RGP protein lens deposits
- 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
33
name three types of protein deposits found on RGP lenses
- lysozyme
- albumin
- globulin
34
which type of protein deposit makes up 40% go tears
lysozymes
35
how do you pick up on scratches on a RGP lens
by viewing it on the eye with the white light on the slit lamp
36
what do you need to observe when assessing scratches on an RGP lens
is it one or both lenses scratched
37
what is the severity range of scratches on RGP lenses
mild to deep
38
what can deep scratches in RGP lenses cause potential for
- microbes to accumulate
| - infection
39
what can be indicated if one RGP lens is scratched
the px may have just dropped the lens
40
what can be indicated if both RGP lenses are scratched
it could be down to the handling of the lens which can be found out in history and symptoms
41
which type of RGP lenses does surface crazing occur in
usually with softer materials
42
what can cause an RGP lens to have surface crazing
handling and flexure which can cause a break down of material
43
what are the 2 actions can you take on RGP lens crazing
- replace with different material i.e. firmer
| - watch how the patient puts their lenses in and re-educate if need be
44
what symptom will a patient with surface crazing on their RGP lens have and why
they can't see well through their lenses as light will be reflecting everywhere
45
how will you check for chips on RGP lenses
by checking all edges of the lens
46
where can chips on an RGP lens be found
front of lens or back of lens
47
what will happen if the chip is on the back of the RGP lens
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
what will happen if the chip is on the front of the RGP lens
the patient won't notice it and the eye is less vulnerable to breaks
49
what can be the cause of chips on a RGP lens
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
what action is required if chips are found on an RGP lens
replace the lens
51
how will you check for chips on a lens whilst in the patient's eye
- check with white light on the slit lamp
| - once the lens is taken out, check for staining with flourescein
52
what is the sign of a manufacturing issue of the RGP lens
there will be a steaming effect
53
what 2 things can a manufacturing issue of a RGP lens be due to
- heat
or
- a solvent
54
what is done to new RGP lenses before given to the patient to avoid manufacturing issue
New lenses soaked for at
least 24 hours prior to
collection and parameters
verified
55
what action needs to be taken with RGP lenses that have a manufacturing issue
replace the lens
56
what will be the signs of dehydration on a SCL
- always usually inferior
| - might see SMILE stain on the cornea if dehydration is excessive
57
what is the cause of dehydration related staining on a SCL
the blink pattern being incomplete, a lack of blinking
58
what 3 actions can be taken for patients who have dehydration of their SCL
```
- Rehydration-break from
lens wear, put lenses
back in case
- Change material
- Blink!
```
59
which type of SCLs is lipid deposits associated with
FDA group 2 and silicone hydrogel lenses
60
what are the three causes of lipid deposits on SCLs
- tear lipids
- cosmetics
- MGD?
61
what are the 2 signs/symptoms of lipid deposits on SCLs
- smeary vision
| - colour fringes
62
what can happen to toric soft lenses which has lipid deposits on them and why
- they can destabilise
| - it weighs the lens down and rotates it
63
what 4 actions can be taken on lipid deposits on SCLs
- Review care routine
- Increase lens replacement frequency (if they're monthlies, switch to dailies)
- Change material
- Treat any MGD
64
which type of SCLs is protein deposits more common in
FDA group 4
65
where to the protein deposits on SCLs come from
from the tear proteins
66
what is the appearance of protein deposits found on SCLs
Film/sheet or can be deposits
67
what can denatured proteins on SCLs lead to
palpebral conjunctival problems
68
what symptom can a patient with protein deposits on their SCL have
increased lens awareness
69
what 3 actions can be taken for protein deposits on SCLs
- 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
which SCL deposit is easy to pick up on
jelly bumps
71
what are jelly bumps found on SCLs
Focal, gelatinous lumps
72
what 3 things are jelly bumps found on SCLs made up of
Mucous, lipid protein and calcium build up
73
which SCLs is jelly bumps common in
FDA group 2 lenses
74
what can the symptoms of jelly bumps found on SCLs range from and wha does this depend on
- no discomfort to moderate discomfort
| - depends on the size and amount of the deposits
75
what 3 actions an be taken on jelly bumps found on SCLs
- Review care routine
- Increase lens replacement
frequency (switch to dailies)
- Change material-to LWC
76
which type of SCL deposit is rare
fungal
77
what causes fungal deposits on SCLs
- Contamination of lens by fungus
| - Areas of growth over lens
78
what 2 things is fungal deposits on SCLs associated with
- 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
what 4 actions is required for fungal deposits on SCLs
- Need to replace lens
- Review hygiene
- Care regimen
- Dailies may be better (as fungus cannot grow on them)
80
what are rust spots in SCLs
a metallic particle found on the SCL
81
when will a patient not notice a rust spot on their SCL
if its on the front surface
82
when will a patient notice a rust spot on their SCL
if its on the back surface
83
where can rust spots found on SCLs come from
the atmosphere
84
what acton is required if a rust spot is found on a SCL
replace the lens
85
what will you do as precaution when detecting a rust spot
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
what 3 things can be the cause of lens damage of a SCL
- Poor handling e.g. long nails
- Lens trapped in case
- New wearers?
87
what can be a sign on lens damage of a SCL
may have staining
88
name 2 examples of types of lens damage of SCLs
- lens splitting
| - chipped edge
89
what 2 actions can be taken for lens damage of a SCL
- Replace lens
- Review handling of
lens, storage, I and R
90
what 3 colours can a SCL discolour to
- brown
- pink
- white
91
how will you investigate SCL discolouration
off the eye
92
list 5 possible causes of SCL discolouration
```
- Nicotine, other fumes,
sprays
- Hormones
- Reaction with tears
- Topical medications
- Ageing of lens (don't change lens when supposed to)
```
93
what will you recommend for someone who has lens discolouration due to nicotine from smoking
stick to daily lenses
94
what is a common problem of silicone hydrogel SCLs
lipid deposits
| produces greasy smeary vision
95
what 4 actions can be taken for silicone hydrogel lenses that has lipid deposits
- Change lens
- Review cleaning
- Changing lens modality may help (change more frequently)
- May need to refit with different material
96
how are lipid on silicone hydrogel lenses prevented
there is now a coating on silicone hydrogel lenses to prevent this
97
when can makeup on a lens be an issue
particularly if lens is not a daily disposable
98
what can makeup on a lens cause and in particular which type of make up
it can cause infections whereby the source comes from mascara which is not replaced regularly
99
what 2 things can you do to prevent makeup on a lens
- Re-educate patient
| - Advise, lenses first, make up after
100
what must a px do if they get an infection due to their mascara
they must throw it and any other eye makeup used on the eye away in the bin
101
lens conditions may be....
graded
102
name 2 examples of grading systems used for and associated with contact lens
- Contact lens opacity grading system (CLOGS)
| - The RUDKO/modified RUDKO scale
