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OD3 (S1&2) > CLM - Contact Lens Complications - PAP Week 3 > Flashcards

CLM - Contact Lens Complications - PAP Week 3 Flashcards

1
Q

Are contact lens complications a major problem?

A

Yes, up to 50% of patients will experience at least one complication

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2
Q

What is the largest risk factor for microbial keratitis?

A

Contact lens wear

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3
Q

What are the four main factors that contribute to contact lens complications?

A

Inflammation, allergy, sensitisation
Mechanical rubbing / poor fit
Microbiological agents
Hypoxia

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4
Q

Between male and female, which is at higher risk of contact lens complications?

A

Male

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5
Q

List 5 risk multipliers for contact lens complications.

A

Dry eye
Male
Smoker
Extended wear
Lifestyle

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6
Q

What percentage of patients wearing contact lenses report at least one hygiene habit that puts them at risk of infection?

A

99%

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7
Q

Does a significant portion of contact lens wearers (RGP included) replace their lenses at an interval longer than recommended?

A

Yes, up to 90%

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8
Q

Compare the proportion of individuals storing or rinsing their lenses in tap water in soft vs rigid lens wearers.

A

Much higher in those wearing rigid lenses to use tap water vs soft lens wearers

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9
Q

What are the most common presenting complaints for contact lens complications (4)?

A

VA
Photophobia
Pain (quantify /10)
Red/itchy eye

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10
Q

What 9 things should be ruled out when evaluating a suspected contact lens complication case?

A

Viral
HSV/HZV keratitis
Chlamydia
Rosacea
Atopy
Episcleritis/scleritis
Oclar surface disease
Corneal dystrophy/degeneration
Autoimmune disease

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11
Q

What can a wratten filter reveal and how?

A

It enhances NaFl visibility and reveals subtle staining

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12
Q

Is rose bengal toxic to the ocular surface or is it like NaFl? Do either of these dyes sting? What about lissamine green?

A

Rose bengal is toxic and therefore stings.
NaFl does not.
Lissamine green is less toxic and irritating (vs rose bengal).

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13
Q

What is the purpose ofa grading scale (2)?

A

Allows monitoring over time
Allows monitoring between clinicians

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14
Q

Should decimals be used in grading scales?

A

Daryl says no, but this one said yes for more sensitivity in monitor change so idk

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15
Q

For the following grades, describe if action is usually taken (for contact lens complications):
Normal (0)
Trace (1)
Mild (2)
Moderate (3)
Severe (4)

A

Normal - not required
Trace - rarely required
Mild - may be required
Moderate - usually required
Severe - definitely required

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16
Q

What is the recommended management for hypoxia related contact lens complications (2)?

A

Increase Dk/t or decrease WT
Maybe consider daily disposables

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17
Q

Why does epithelial loss cause pain?

A

It exposes nerve endings

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18
Q

How long does it take for superficial vs deep staining to heal? If the patient has superficial staining, can they still wear their lenses? What about deep staining?

A

Superifical - within 24h
-Patient can continue wearing lenses
Deep - within 1-2 days
-best id patient stops wearing lenses for 2-4 days (treat the cause in the meantime)

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19
Q

What should be considered if there is a defect to the corneal stroma (2)?

A

Consider prophylactic antibiotics
-0.5% chlorsig
-aminoglycoside for better gram negative coverage

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20
Q

In what five ways does the eye prevent bacterial colonisation?

A

Cell shedding
Wiping action of blinking
Irrigation by lacrimal secretions
Antimicrobials in tears
Competition by resident microbes

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21
Q

If there are satellite lesions, what does it decrease the likelihood of the diagnosis being?

A

Bacterial MK

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22
Q

What are most cases of microbial keratitis caused by?

A

Pseudomonas sp.

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23
Q

What are two characteristics of an acanthamoeba infection?

A

Ring infiltrate and extreme pain

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24
Q

When is acanthamoeba infection generally diagnosed?

A

When bacterial management isnt working

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25
Q

Should you refer if there are any lesions on the visual axis?

A

Yes

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26
Q

Are there any safety concerns with adjunctive corticosteroid therapy for bacterial corneal ulcers?

A

No

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27
Q

What is the association between visual outcomes in individuals with bacterial keratitis and high-dose steroid treatment?

A

Significantly associated with better visual outcomes

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28
Q

List 5 factors that are significantly associated with visual outcomes in keratitis.

A

High dose steroid treatment
Visual acuity on presentation
Age group
Cause of keratitis
Infiltrate size/location

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29
Q

List three possible causes of infiltrates.

A

Poor compliance
MGD / blepharitis
Hypersensitivity
-lens
-solution
-bacteria

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30
Q

List four management options for infiltrates.

A

Cease lens wear
Steroid/antibiotic
Change lens type/modality/WT
If infection suspected, treat as infectious

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31
Q

When should an infiltrate case be reviewed after initial assessment and management?

A

Review in 24h

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32
Q

Can infiltrates lead to scarring?

A

Yes

33
Q

What is the cause of CLARE (2)?

A

Immune response to acute or chronic hypoxia
There may be the presence of high bacterial load on the contact lens, being trapped in close proximity to the ocular surface

34
Q

In what modality is CLARE common?

A

Extended wear

35
Q

What fit of soft lenses can often lead to CLARE and why?

A

Tight lenses due to the lack of tear exchange to flush out bacterial toxins

36
Q

What gram type bacteria are often the cause of CLARE?

A

Negative

37
Q

List 10 signs of CLARE.

A

Painful red eye, may or may not have photophobia
Diffuse and focal infiltration
Corneal epithelial and stromal oedema
Conjunctival and limbal oedema and injection
Peripheral, multiple culture negative infiltrates

38
Q

List three possible management options for CLARE.

A

Cease contact lens wear
Consider steroids
Consider prophylactic antibiotics or if infection is suspected

39
Q

Does mechanical irritation occur more often in soft or rigid lenses?

A

Soft (5-10%), while rigid is lower (3-5%)

40
Q

List 5 factors associated with mechanical irritation/inflammation/allergic response.

A

Soft (5-10%)/RGP (3-5%) lenses
Prosthetic devices
Exposed sutures
Glaucoma filtering blebs
Corneal scars

41
Q

Compare the histology of follicles to papillae.

A

Follicles are hyperplasic lymphoid tissue
Papillae are hyperplasic conjunctival epithelium

42
Q

Are follicles mostly found in the upper or lower lid? What about papillae?

A

Follicles - inferior (forniceal conj)
Papillae - superior (palpebral conj)

43
Q

Where do papillae first appear?

A

At the margin of the tarsal plate

44
Q

What are the two major causes of papillae?

A

CLPC
Vernal conjunctivitis

45
Q

What are the two major causes of follicles?

A

Viral infections and hypersensitivity to solutions

46
Q

How is contact-lens associated papillary conjunctivitis (CLPC) treated? How long can it take? What can it lead to if untreated?

A

At grade 3-4, may need to cease lens wear and use therapeutics until resolved
May take 1-6 months of treatment
If untreated for years, may lead to conjunctival scarring (possibly corneal scarring)

47
Q

List 6 mechanical complications of contact lenses.

A

FB staining
RGP and SCL binding
Epithelial wrinkling
Bubble indentations
Mucin balls
Superior epithelial arcuate lesions

48
Q

How Does FB staining appear on examination and how is it caused?

A

When a foreign body gets stuck behind the lens and as the patient blinks, it moves around behind the lens and damages the cornea.

49
Q

What is dimple veiling, what is it caused by, and individuals with what disease are most affected by this?

A

Depressions caused by trapped bubbles
Mostly affects keratoconics

50
Q

Are dimple veilings actual staining? Explain.

A

No, it is just a pooling of NaFl in indentations made by bubbles

51
Q

List two signs and a symptom of SEALs.

A

Signs
-epithelial split
-stains with NaFl
Symptoms
-discomfort to severe pain

52
Q

List three possible causes of SEALs.

A

Lens thickness
Modulus
Lid force (tight lids)

53
Q

What kind of lens are SEALs more common with?

A

SiHy

54
Q

List three treatment options for SEALs.

A

Discontinue wear until resolved ~1-2 weeks
Change SCL design to softer modulus
Change to RGPs

55
Q

In what kind of modulus lenses do mucin balls tend to occur and how? Explain why the staining appears the way it does and whether or not it is true staining.

A

Higher modulus lenses
Occurs due to the interaction of the lens surface and corneal epithelium
Not punctate staining, they are indentations

56
Q

List three consequences of hypoxia to the corneal epithelium.

A

Cell loss
Microcysts
Vacuoles

57
Q

List three consequences of hypoxia to the corneal stroma.

A

Transparency
Striae
Folds

58
Q

List four consequences of hypoxia to the corneal endothelium.

A

Blebs
Polymegathism
Pleomorphism
Bedewing

59
Q

List three general consequences of hypoxia to the cornea.

A

Neovascularisation
Corneal exhaustion syndrome
Superior limbic keratoconjunctivitis

60
Q

List four aetiologies of neovascularisation.

A

Chronic oedema
Stromal softening
Mechanical irritation
Inflammatory response

61
Q

Is no vessel ingrowth acceptable with modern contact lenses?

A

Yes

62
Q

List four characteristics of neovascularisation that should be assessed on examination.

A

Depth
Associated pannus
Location
Presence of leucocytes

63
Q

What are microcysts and what layer of the cornea are they in?

A

Pockets of cellular debris in the epithelium

64
Q

What are microcysts associated with? In what modality are they typically only seen now?

A

Hypoxia
Now almost only seen in extended wear

65
Q

Do microcysts migrate or stay put?

A

Migrate with the surrounding cells

66
Q

Is the presence of a few microcysts normal or is this a sign of some level of hypoxia?

A

A few are normal

67
Q

Do microcysts always stain with NaFl?

A

Small NaFl stain only when it reaches the surface

68
Q

How do microcysts appear?

A

Seen as small inclusions in the epithelium at 40x

69
Q

List a symptom of microcysts.

A

None khe

70
Q

List three management options for microcysts.

A

Improve Dk/L
Decrease wear time
Reduce or cease extended wear

71
Q

How can vacuoles and microcysts be distinguished?

A

Microcysts generally appear darker with direct illumination - reversed illumination
Vacuoles tend to light up with direct illumination - unreversed illumination

72
Q

List four stromal signs of swelling.

A

Minor loss of transparency
Striae
Significant loss of transparency
Folds

73
Q

Are stromal swelling signs acute or chronic?

A

Acute and develop within minutes or hours

74
Q

What is the acute response of the endothelium to hypoxia (2)?

A

Blebs
Bedewing

75
Q

What is the chronic response of the endothelium to hypoxia (2)?

A

Polymegathism and pleomorphism

76
Q

List three management options for hypoxia.

A

Increased Dk/L
Improved tear exchange (RGPs)
Reduced wearing time

77
Q

List two ways Dk/L can be increased.

A

Increase Dk
Decrease average thickness

78
Q

What is the minimum Dk according to the Holden-Mertz criteria for daily and extended wear lenses?

A

Daily - 24
Extended - 87

OD3 (S1&2) (114 decks)

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