CLM - Contact Lens Complications - PAP Week 3 Flashcards by B H

Are contact lens complications a major problem?

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

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What is the largest risk factor for microbial keratitis?

Contact lens wear

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

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

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

Male

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List 5 risk multipliers for contact lens complications.

Dry eye
Male
Smoker
Extended wear
Lifestyle

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

99%

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

Yes, up to 90%

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

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

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

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

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

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

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What can a wratten filter reveal and how?

It enhances NaFl visibility and reveals subtle staining

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

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

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What is the purpose ofa grading scale (2)?

Allows monitoring over time
Allows monitoring between clinicians

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Should decimals be used in grading scales?

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

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

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

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

Increase Dk/t or decrease WT
Maybe consider daily disposables

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Why does epithelial loss cause pain?

It exposes nerve endings

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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?

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

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

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In what five ways does the eye prevent bacterial colonisation?

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

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

Bacterial MK

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What are most cases of microbial keratitis caused by?

Pseudomonas sp.

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What are two characteristics of an acanthamoeba infection?

Ring infiltrate and extreme pain

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When is acanthamoeba infection generally diagnosed?

When bacterial management isnt working

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

Yes

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

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

Significantly associated with better visual outcomes

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

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

List three possible causes of infiltrates.

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

List four management options for infiltrates.

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

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

Review in 24h

Can infiltrates lead to scarring?

Yes

What is the cause of CLARE (2)?

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

In what modality is CLARE common?

Extended wear

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

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

What gram type bacteria are often the cause of CLARE?

Negative

List 10 signs of CLARE.

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

List three possible management options for CLARE.

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

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

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

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

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

Compare the histology of follicles to papillae.

Follicles are hyperplasic lymphoid tissue Papillae are hyperplasic conjunctival epithelium

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

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

Where do papillae first appear?

At the margin of the tarsal plate

What are the two major causes of papillae?

CLPC Vernal conjunctivitis

What are the two major causes of follicles?

Viral infections and hypersensitivity to solutions

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

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)

List 6 mechanical complications of contact lenses.

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

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

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

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

Depressions caused by trapped bubbles Mostly affects keratoconics

Are dimple veilings actual staining? Explain.

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

List two signs and a symptom of SEALs.

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

List three possible causes of SEALs.

Lens thickness Modulus Lid force (tight lids)

What kind of lens are SEALs more common with?

SiHy

List three treatment options for SEALs.

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

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.

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

List three consequences of hypoxia to the corneal epithelium.

Cell loss Microcysts Vacuoles

List three consequences of hypoxia to the corneal stroma.

Transparency Striae Folds

List four consequences of hypoxia to the corneal endothelium.

Blebs Polymegathism Pleomorphism Bedewing

List three general consequences of hypoxia to the cornea.

Neovascularisation Corneal exhaustion syndrome Superior limbic keratoconjunctivitis

List four aetiologies of neovascularisation.

Chronic oedema Stromal softening Mechanical irritation Inflammatory response

Is no vessel ingrowth acceptable with modern contact lenses?

Yes

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

Depth Associated pannus Location Presence of leucocytes

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

Pockets of cellular debris in the epithelium

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

Hypoxia Now almost only seen in extended wear

Do microcysts migrate or stay put?

Migrate with the surrounding cells

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

A few are normal

Do microcysts always stain with NaFl?

Small NaFl stain only when it reaches the surface

How do microcysts appear?

Seen as small inclusions in the epithelium at 40x

List a symptom of microcysts.

None khe

List three management options for microcysts.

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

How can vacuoles and microcysts be distinguished?

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

List four stromal signs of swelling.

Minor loss of transparency Striae Significant loss of transparency Folds

Are stromal swelling signs acute or chronic?

Acute and develop within minutes or hours

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

Blebs Bedewing

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

Polymegathism and pleomorphism

List three management options for hypoxia.

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

List two ways Dk/L can be increased.

Increase Dk Decrease average thickness

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

Daily - 24 Extended - 87