CLM - Contact Lens Complications - PAP Week 3 Flashcards
Are contact lens complications a major problem?
Yes, up to 50% of patients will experience at least one complication
What is the largest risk factor for microbial keratitis?
Contact lens wear
What are the four main factors that contribute to contact lens complications?
Inflammation, allergy, sensitisation
Mechanical rubbing / poor fit
Microbiological agents
Hypoxia
Between male and female, which is at higher risk of contact lens complications?
Male
List 5 risk multipliers for contact lens complications.
Dry eye
Male
Smoker
Extended wear
Lifestyle
What percentage of patients wearing contact lenses report at least one hygiene habit that puts them at risk of infection?
99%
Does a significant portion of contact lens wearers (RGP included) replace their lenses at an interval longer than recommended?
Yes, up to 90%
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
What are the most common presenting complaints for contact lens complications (4)?
VA
Photophobia
Pain (quantify /10)
Red/itchy eye
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
What can a wratten filter reveal and how?
It enhances NaFl visibility and reveals subtle staining
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).
What is the purpose ofa grading scale (2)?
Allows monitoring over time
Allows monitoring between clinicians
Should decimals be used in grading scales?
Daryl says no, but this one said yes for more sensitivity in monitor change so idk
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
What is the recommended management for hypoxia related contact lens complications (2)?
Increase Dk/t or decrease WT
Maybe consider daily disposables
Why does epithelial loss cause pain?
It exposes nerve endings
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)
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
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
If there are satellite lesions, what does it decrease the likelihood of the diagnosis being?
Bacterial MK
What are most cases of microbial keratitis caused by?
Pseudomonas sp.
What are two characteristics of an acanthamoeba infection?
Ring infiltrate and extreme pain
When is acanthamoeba infection generally diagnosed?
When bacterial management isnt working
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?
No
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
