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AOS1 - Week 5 > Soft Contact Lens Complications > Flashcards

Soft Contact Lens Complications Flashcards

1
Q

How does CLs break down normal defence mechanisms?

A
  • damage to the corneal epithelium
  • distribution normal homeostatic surface renewal
  • reduction of tear flow and stagnation of post -lens tear film
  • Breakdown of defence mechanism predispose the cornea to infection
  • Preservatives in MPS can alter the epithelial cell desquamation and further increase the risk of MK
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2
Q

What is the treatment for infections?

A
  • cease lens wear
  • immediate treatment/referral required
  • aggressive antimicrobial treatment
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3
Q

What is bacterial keratitis?

A
  • It is an infection of the cornea
    this requires urgent medical attention due to the serious risk of corneal perforation and sight loss
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4
Q

What is the clinical presentation of bacterial keratitis?

A
  • Slit lamp examination reveals an excavation with underlying infiltrate
  • generally central or paracentral
  • AC reaction may be present
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5
Q

What are the symptoms of bacterial keratitis?

A

severe pain/photophobia, epiphora, conjunctival chemosis, lid oedema

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6
Q

What is inflammation?

A

Accumulation of proteins, lipids or by-products that adhere to the surface of a contact lens can cause inflammation in the cornea or conjunctiva

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7
Q

What is the treatment for inflammation?

A
  • cease lens wear immediately
  • address any causative factors
  • topical steroid +- prophylactic antibiotic, ocular lubricant
  • reduce wear time
  • increase replacement frequency
  • increase lens movement
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8
Q

What is CL associated peripheral ulcer?

A
  • non infectious, infiltrative response to bacteria
    This requires urgent medical attention due to the serious risk of corneal perforation and sight loss
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9
Q

What is the clinical presentation of CL associated ulcer?

A

epithelial excavation or non staining white spot in the peripheral regions of the cornea

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10
Q

What are the symptoms of CL associated peripheral ulcer?

A
  • FB sensation, mild irritation, awareness of redness an infiltrate
  • reduced wear time
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11
Q

What is CL associated Red eye (CLARE)?

A

Related to the overwear of contact lens, toxins under the lens. This requires active mx to prevent reoccurance

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12
Q

What is the clinical presentation of CLARE?

A
  • global conjunctival redness and chemosis
  • watery discharge
  • +- diffuse scattered infiltrates/SPK
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13
Q

What is superior limbic keratitis?

A

Can lead to micropannus, papillary hypertrophy and corneal warpage if left untreated

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14
Q

What is the clinical presentation of SLK?

A
  • Punctate NaFl staining on the superior cornea, associated infiltrates and limbal hyperemia
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15
Q

What are the symptoms of SLK?

A

Irritation/discomfort, increased lens awareness, may develop photophobia

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16
Q

What is hypoxia?

A

Reduced oxygen = change in corneal metabolism - build up of lactic acid - osmotic load = drawing water into the cornea faster than it can be removed = corneal oedema
- Lens induced hypoxia key mediator for microbial invasion by pseudomonas

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17
Q

What is the treatment for hypoxia?

A
  • cease lens wear
  • increase Dk/t
  • reduce wear time
  • change lens type
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18
Q

What is limbal hyperemia?

A
  • swollen limbal vessels
    If left untreated could lead to discomfort, inflammatory response or infection
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19
Q

What is the clinical presentation for limbal hyperemia?

A

Annular or sectoral redness/injection

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20
Q

What are the symptoms of limbal hyperemia?

A
  • pain which suggests corneal involvement
  • asymptomatic suggests conjunctival involvement
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21
Q

What is neovascularisation?

A
  • invasion of new blood vessels in the cornea
    Indication that the cornea is under hypoxic stress, if ignored it has potential to extend to pupil zone = visual loss
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22
Q

What is the clinical presentation of neovascularisation?

A
  • stromal extension of limbal vascular network
  • start superficial at limbus then branch and go deeper into stroma
23
Q

What are the symptoms of neovascularisation?

A

asymptomatic

24
Q

What is stromal oedema?

A

vertical lines visible within the stroma under moderate to high magnification

25
Q

What are the symptoms of stromal oedema?

A
  • asymptomatic if mild
  • reduced wear time, blur and discomfort if more severe
26
Q

What is the clinical impact of stromal oedema?

A

can lead to stromal thinning or opacification in long-term

27
Q

What are microcysts/vacuoles?

A

The sphere of necrotic cells that develop within the epithelial layers and migrate to the surface
- these indicate chronic hypoxia or recovery from hypoxia

28
Q

What is the clinical presentation of microcysts/vacuoles?

A

minute scattered spherical dots observable under high magnification

29
Q

What is toxicity?

A

Combination of chemical preservatives used in lens care produces and specific SiH lens polymers can have adverse impact on the ocular surface

30
Q

What is solution-induced corneal staining?

A

Bilateral mild punctate staining observed, maximum intensity at 2 hr of wear and resolved by 6 hrs
- seen in SCL weares using MPDS

31
Q

What are the symptoms for solution-induced corneal staining?

A

asymptomatic or dryness and discomfort

32
Q

What is the mx of solution-induced corneal staining?

A
  • cease lens wear until staining resolves
  • change away from lens materials or lens care that induces SICS
33
Q

What is dryness?

A

Accumulation of inflammatory molecules, stagnant tear film and less mucins = destruction of tight junctions and sloughing of epithelia

34
Q

What is the mx of dryness?

A
  • ocular lubricants
  • vitamin A, omega 3 and/or omega 6 fatty acid supplementation
  • consider lens design/modality
    -consider care system
35
Q

What is tear film instability?

A

Unstable tear film that has reduced TBUT, increased debris/oily surface

36
Q

What is the clinical impact of tear film instability?

A
  • Leads to conjunctival hyperemia, corneal staining, lid wiper epitheliopathy
  • Lens surface deposits
  • CL may not be very successful in moderate/severe dry eye px
37
Q

What are the symptoms of tear film instability?

A

blur, burning, itching, grittiness, mild photophobia

38
Q

What is CL associated dry eye?

A

conjunctival or limbal redness
- corneal desiccation (corneal not resurfaced with tears)
- poor tear film

39
Q

What are the symptoms of CL associated dry eye?

A
  • asymptomatic with no lens wear
  • develops dry eye symptoms with lens wear: soreness, irritation, burning, redness
  • worse as day progresses
40
Q

What is mechanical impact?

A

Mechanical factors causing irritation to the ocular surface or tarsal conjunctival have an impact on corneal physiology
- factors include: lens material, inappropriate lens design, improper lens fitting

41
Q

What is conjunctival staining?

A

staining result of the lens fit; either tight, little movement or lens edge positive impression
- may be an indication of CL associated dry eye

42
Q

What is the clinical presentation of conjunctival staining ?

A

localised indentation arc- apparent with NaFl and LG staining
- physical trauma from lens edge or excessive movement

43
Q

What are conjunctival folds?

A

chemosis of epithelium leading to folds/flaps
- associated with higher modulus lenses

44
Q

What is the tx for conjunctival folds?

A
  • refit with lower modulus lens
  • reduce wear time
  • ocular lubricants
45
Q

What is CLAPC ?

A

combo allergic reaction to lens adherent proteins/lipids and response to mechanical irritation
- related to extended/over wear

46
Q

What is the clinical presentation CLAPC?

A
  • Usually upper lid, increased redness, localised papillae
  • NaFl exaggerates apperance
47
Q

What is the Mx for CLAPC?

A
  • cease/reduce cl wear
  • refit with alternate lens type
  • reduce wear time/proper care
  • AH/MCS combo for weeks-months. topical steroids (qid for weeks) if mod-severe
48
Q

What is a superior epithelial arcuate lesion?

A
  • progressive in nature, increasing discomfort
  • increased risk of infection
  • will lead to lens discontinuation
49
Q

What is the clinical presentation of a superior arcuate lesion?

A

superior corneal staining parallel to upper limbus
- can cause discomfort

50
Q

What is the mx for a superior arcuate lesion?

A
  • cease lens wear until healed
  • alter lens design
  • prophylactic antibiotics while healing
51
Q

What are foreign body lesions?

A

trapped foreign body that result in epithelial disruption highlighted by NaFl
- this increases risk of infection
- recurrent lesion can indicate poor tear exchange

52
Q

What is the mx for foreign body lesions?

A
  • cease lens wear
  • prophylactic antibiotic (depending on severity)
  • change in lens design
53
Q

What are mucin balls?

A

observed during lens removal, initially immobile round spherical objects

AOS1 - Week 5 (3 decks)

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