Contact lens surface changes Flashcards
list 5 contact lens surface changes associated with RGP lenses
- Lens debris
- Lens drying
- Poor wetting
- Lens deposits
- Lipids
- Proteins
- Lens damage:
- Scratches
- Crazing
- Chips
- Manufacturing issues
what are the 2 types of lens deposits associated with RGP lenses
- lipids
- proteins
what are the 4 types of lens damage associated with RGP lenses
- Scratches
- Crazing
- Chips
- Manufacturing issues
what 5 contact lens surface changes are associated with SCL
- Dehydration
- Lens deposits
- Lipids
- Protein deposits
- Calcium
- Jelly bumps
- Fungal
- Rust spots
- Lens damage
- Lens discolouration
what are the 5 types of lens deposits associated with soft contact lenses
- Lipids
- Protein deposits
- Calcium
- Jelly bumps
- Fungal
what are the 3 places lens debris on a RGP come from
- biological
- microbiological
- environmental
name examples of biological lens debris found on RGP lenses
- tear film/bits in tears
- skin cells
name examples of microbiological debris found on RGP lenses and the cause of this
- bacteria
- fungi
- viruses
from not cleaning the lenses well enough or not washing hands before handling lenses
name examples of environmental debris found on RGP lenses
- make up
- aerosols
which 2 locations can lens debris be found on a RGP lens
- central
or - edge
if lens debris on a RGP lens is found centrally, what can this indicate
that something has just happened recently and has attached itself on the front surface of the lens
if lens debris on a RGP lens is found around the edge, what can this indicate
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
what can you do in practice to pick up on lens debris on a RGP lens and what will be your management
- do a flourescein staining check as it will attach to the lens debris
- if this occurs, just replace the RGP lens
what can happen to the RGP lens if too much debris is found on its surface
it can weigh down the lens
what may mask lens drying on a RGP lens
rapid blinking
what may a patient not report with RGP lens drying
any symptoms
as they will just blink more rapidly without realising
they may just say their vision isn’t very clear
how will you assess lens drying of an RGP on the slit lamp
- 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
for what 4 reasons can poor wetting of an RGP lens be caused by
- if the lens is too old, it might not wet
- a build up of deposits: can hinder its wetting
- poor tear film quality
- MGD
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
the inter-palpebral blink rate
what is a symptom of poor wetting of an RGP lens
reduced lens tolerance/wear times
what does the action of treating poor wetting of an RGP lens depend on
the aetiology
list 3 actions that can be done for a poor RGP lens wetting
- Review material/cleaning/care
regimen - Rewetting drops
- Replace lens?
which type of cleaning solution can be used to improve the wettability of an RGP lens and why
cleaning solutions such as boston advance, as it has friction enhancers that can rub off most of the deposits
what affects the type of deposition found on a lens and explain how
- 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
which type of RGP cleaner is designed to repel lens deposits
surfactant cleaner
what is the appearance of lipid RGP lens deposits
- colour fringes
- glossy appearance which is greasy and shiny
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
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
what is the appearance of protein RGP lens deposits
- matt
- opaque/white
- diffuse film
what may be affected with protein deposits on RGP lenses
VA
what can protein deposits on RGP lenses lead to
induced papillary conjunctivitis
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
name three types of protein deposits found on RGP lenses
- lysozyme
- albumin
- globulin
which type of protein deposit makes up 40% go tears
lysozymes
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
what do you need to observe when assessing scratches on an RGP lens
is it one or both lenses scratched
what is the severity range of scratches on RGP lenses
mild to deep
what can deep scratches in RGP lenses cause potential for
- microbes to accumulate
- infection
what can be indicated if one RGP lens is scratched
the px may have just dropped the lens
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
which type of RGP lenses does surface crazing occur in
usually with softer materials
what can cause an RGP lens to have surface crazing
handling and flexure which can cause a break down of material
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
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
how will you check for chips on RGP lenses
by checking all edges of the lens
where can chips on an RGP lens be found
front of lens or back of lens
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
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
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
what action is required if chips are found on an RGP lens
replace the lens
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
what is the sign of a manufacturing issue of the RGP lens
there will be a steaming effect
what 2 things can a manufacturing issue of a RGP lens be due to
- heat
or - a solvent
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
what action needs to be taken with RGP lenses that have a manufacturing issue
replace the lens
what will be the signs of dehydration on a SCL
- always usually inferior
- might see SMILE stain on the cornea if dehydration is excessive
what is the cause of dehydration related staining on a SCL
the blink pattern being incomplete, a lack of blinking
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!
which type of SCLs is lipid deposits associated with
FDA group 2 and silicone hydrogel lenses
what are the three causes of lipid deposits on SCLs
- tear lipids
- cosmetics
- MGD?
what are the 2 signs/symptoms of lipid deposits on SCLs
- smeary vision
- colour fringes
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
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
which type of SCLs is protein deposits more common in
FDA group 4
where to the protein deposits on SCLs come from
from the tear proteins
what is the appearance of protein deposits found on SCLs
Film/sheet or can be deposits
what can denatured proteins on SCLs lead to
palpebral conjunctival problems
what symptom can a patient with protein deposits on their SCL have
increased lens awareness
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
which SCL deposit is easy to pick up on
jelly bumps
what are jelly bumps found on SCLs
Focal, gelatinous lumps
what 3 things are jelly bumps found on SCLs made up of
Mucous, lipid protein and calcium build up
which SCLs is jelly bumps common in
FDA group 2 lenses
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
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
which type of SCL deposit is rare
fungal
what causes fungal deposits on SCLs
- Contamination of lens by fungus
- Areas of growth over lens
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
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)
what are rust spots in SCLs
a metallic particle found on the SCL
when will a patient not notice a rust spot on their SCL
if its on the front surface
when will a patient notice a rust spot on their SCL
if its on the back surface
where can rust spots found on SCLs come from
the atmosphere
what acton is required if a rust spot is found on a SCL
replace the lens
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
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?
what can be a sign on lens damage of a SCL
may have staining
name 2 examples of types of lens damage of SCLs
- lens splitting
- chipped edge
what 2 actions can be taken for lens damage of a SCL
- Replace lens
- Review handling of
lens, storage, I and R
what 3 colours can a SCL discolour to
- brown
- pink
- white
how will you investigate SCL discolouration
off the eye
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)
what will you recommend for someone who has lens discolouration due to nicotine from smoking
stick to daily lenses
what is a common problem of silicone hydrogel SCLs
lipid deposits
produces greasy smeary vision
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
how are lipid on silicone hydrogel lenses prevented
there is now a coating on silicone hydrogel lenses to prevent this
when can makeup on a lens be an issue
particularly if lens is not a daily disposable
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
what 2 things can you do to prevent makeup on a lens
- Re-educate patient
- Advise, lenses first, make up after
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
lens conditions may be….
graded
name 2 examples of grading systems used for and associated with contact lens
- Contact lens opacity grading system (CLOGS)
- The RUDKO/modified RUDKO scale
