contact lenses 4 - complications and aftercare

Question 1

in what 3 moments is contact lens dropout most likely to occur?

Answer 1

-when first fitted with contact lenses
-once becoming an established contact lens wearer
-when reaching presbyopia

most common reasons for these are discomfort and poor vision

Question 2

what are the main problems new spherical lens wearers have to overcome?

Answer 2

handling and discomfort

Question 3

what are the main problems new toric and multifocal lens wearers have to overcome?

Answer 3

visual problems

Question 4

how can you make sure patients are happy with vision aspect of CLs when they are first fitted with them?

Answer 4

• Personalised prescribing for initial lens selection
• Ensure patient is happy with vision at fitting, especially torics and multifocals
• Match lens features to patient requirements (visual task analysis)

Question 5

how can you make sure patients are happy with the handling aspect of CLs when they are first fitted with them?

Answer 5

• Teach experience
• Follow-up call to check progress and reassure
• Offer additional support, change lens brand, increase modulus

Question 6

what is contact lens discomfort (CLD)? How is it different to CL related dry eye or CL induced dry eye?

Answer 6

-episodic or persistent adverse ocular sensations related to lens wear, may or may not affect vision and lead to decreased wearing time and CL dropout
-as CLD describes px with pre-existing dry
eye, which may be exaggerated by CL wear whereas the others did not have dry eye before but after having worn the lenses for a while, they now do

Question 7

how can you manage a patient with CLD?

Answer 7

1. determine the most likely cause
2. identify corresponding treatment strategy
3. stepwise application of treatments to achieve the maximum effect e.g.

-adjust replacement frequency
-change the lens material and/ or design
-tear supplementation
-dietary supplementation
-improve the environment

Question 8

what are the signs contact lens wear has affected the tear film?

Answer 8

-reduced tear film stability due to thinner/absent lipid layer so increased evaporation
-increased osmolarity
-increased inflammatory mediators where sub clinical inflammation was found in even asymptomatic patients
-ocular surface temperature
-deposition of tear film protein and lipid onto the lens surface only take minutes

Question 9

what aspects of CLs affects meibomian gland morphology and function?

Answer 9

• Duration of wear
• Type of lens
• Modulus

Question 10

how do you manage establish lens wearers to prevent them from dropping out?

Answer 10

• Offer convenient options to meet patients changing needs
• Choose products for optimum comfort
• Proactively manage MGD and dry eye
• Offer new lens options

Question 11

why can presbyopia cause CL dropout?

Answer 11

as increasing prevalence of dry eye with age is likely to impact CL comfort

Question 12

how do you clinically manage patients with presbyopia who are CL wearers to prevent dropout?

Answer 12

• Inform patients 40 years+ that near vision changes over time and presbyopic contact lens options are available
• Personalised prescribing - tailor vision correction to individual patient requirements (visual task analysis)
• Choose products for optimum comfort
• Use the fitting guide when fitting multifocals
• Set realistic expectations & explain adaptation issues
• Provide both contact lenses and spectacles to meet the spectrum of
  patient needs

Question 13

what are the 3 dyes that can be used to check corneal staining?

Answer 13

-sodium fluorescein
-rose bengal
-lissamine green

Question 14

what are the types of sodium fluorescein dyes?

Answer 14

• 1 or 2% solution (minim)
• Fluoret (fluorescein impregnated paper strips)
• High molecular weight Fluoresoft (fluorexon)

Question 15

when may you use high molecular weight fluoresoft fluorescein?

Answer 15

may be used in specialist cl fitting where you need fluorescein to aid the fit of the lens without dying the CL like other forms of fluorescein would

otherwise not commonly used as it doesn’t fluoresce well

Question 16

why is rose bengal stain not used much anymore?

Answer 16

t is very painful and this can be made worse with UV lights as well

Question 17

what is lissamine green stain good for?

Answer 17

great for dry eye assessment but not used often as it’s difficult to get a hold of

Question 18

how do you observe corneal staining? how do you set up the slit lamp? What mag should you use?

Answer 18

-in a z shape so scan from bottom to top
-Direct illumination, ~2mm wide beam,
beam 45º angle, max illumination
-Start at 16x, increase for greater detail

Question 19

how can you assess corneal staining?

Answer 19

-using grading scales - CCLRU and effron (grade 1-5 based on which the staining looks most similar to)
-the best way being to draw what you see on record & indicate depth one reason being a small amount of deep staining is more serious than large amounts of superficial staining (this is especially true for effron)

Question 20

how does CCLRU grading for corneal staining work?

Answer 20

you can grade the staining in each of the 3 categories being:
-corneal staining type
-corneal staining depth
-corneal staining extent

Question 21

why can patients sometimes not be able to tell they have a foreign body in their soft CL?

Answer 21

because the soft CL can sometimes act as a bandage where it depresses the scratch created on the cornea as soft CLs generally do not move.

Question 22

what are the three types of corneal staining?

Answer 22

-punctates = most common usually seen as small superficial dots
-diffuse - a vast array of closely separated punctates
-coalescent/ patch which is confluent patch of diffuse staining

Question 23

what are the categories of things that can cause corneal staining?

Answer 23

• Mechanical
• Exposure
• Metabolic
• Toxic
• Allergic
• Infectious

Question 24

how do you manage foreign body staining?

Answer 24

• Remove lens
• Check FB has gone, evert lid
• Replace lens if damaged
  *Use lubricants/ artificial tears to promote healing and reduce discomfort while blinking
• Monitor until resolved

Question 25

how do you differentiate between toxicity staining caused by rgp cleaner / peroxide vs cl solution?

Answer 25

-rgp cleaner/ peroxide is unilateral ( usually unilateral as people usually don’t do it to both eyes) and cl solution is usually bilateral and symmetrical

Question 26

what are signs of toxicity staining caused by cl solution?

Answer 26

-bilateral and symmetrical
-diffuse SPEE (superficial punctate epithelial erosion) across the whole cornea
-stinging on lens insertion
-cl intolerance
-takes weeks/ months to develop

Question 27

how do you manage acute toxicity staining?

Answer 27

acute = peroxide/ RGP cleaner
* Remove lens
* Irrigate
* Monitor
* Educate patient

Question 28

how do you manage chronic toxicity staining?

Answer 28

• Replace lenses
• Trial alternative solution
• Monitor

Question 29

for SICS, what solution lens combos is it associated with?

Answer 29

Polyhexanide (PHMB) preserved lens care solutions & Group II lenses

Question 30

what is SICS staining?

Answer 30

solution induced corneal staining - asymptomatic, transient and reversible staining and sometimes considered benign as initially thought to be a response to preservative interaction with lens deposits

Question 31

how can you manage SICS staining?

Answer 31

-rub and rinse RGPs before overnight soaking
-always teach and remind patients to rub and rinse their lenses on removal
-change to a PHMB free solution
-change to a peroxide preservative free solution
-change to daily disposables

Question 32

what is 3 and 9 o’clock staining?

Answer 32

in RGP wearers where sometimes the lens lift causes areas of the cornea to not get wet and this sometimes. This can sometimes be triggered by incomplete/ infrequent blinking

Question 33

how can you manage 3 and 9 o’clock staining?

Answer 33

-refit of the lenses with a bigger diameter- changing the lens to one with an amended diameter due to it being too flat or too steep
-recommend lubricant drops to help the corneal heal.

Question 34

what is seal staining?

Answer 34

-superior epithelial arcuate lesion and is usually missed as it’s found on the top of the cornea
-typically more common when RGPs were very stiff as this combined with the force of the eyelid caused mechanical chaffing of the cornea but now has a mechanical aetiology in soft lens wearers

Question 35

how do you manage SEAL staining?

Answer 35

• Lenses out initially
• Recommence lens wear &
  monitor
• Refit with tighter lens
• Refit with lower modulus lens

Question 36

what is a smile stain? What is it caused by?

Answer 36

-inferior and arcuate so looks like a smile
-Caused because of dehydration (dessication) of the inferior cornea as the lens causes teg tear film to evaporate Fairly common and can be caused by incomplete blink or dry eye (poor humidity)

Question 37

how do you manage smile staining?

Answer 37

• Incomplete blinking- give
  exercises
• Lens drying- refit
• Dry environment- increase
  humidity

Question 38

what is an epithelial plug? How do you manage it?

Answer 38

staining caused by full thickness epithelial loss due to severe and prolonged hypoxia e.g. sleeping in CLs so you need to refer urgently as has ability to impair vision and cause scarring due to it being in the central cornea

Question 39

what is clpu?

Answer 39

contact lens peripheral ulcer and causes stromal degeneration and overlying epithelial defect - usually caused by non compliance

Question 40

how do you manage CLPU?

Answer 40

remove the lens (this greatly improves the comfort) and monitor carefully

Question 41

what is indentation/ musin ball staining?

Answer 41

not true staining but occurs when something has pushed back into the epithelium (e.g. air bubbles) causing an indent which the fluorescein pools into but is not actual staining

Question 42

how do you manage indentation staining?

Answer 42

• irrigate and if it goes away, then you know it’s not actual staining
  -otherwise refit the lens