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Contact Lenses > RGP Complications > Flashcards

RGP Complications Flashcards

1
Q

What are the areas effected with RGP?

A
  1. Conjunctiva : Bublar, palpebral
  2. Cornea : Epithelium, Stroma and Ednothelium
  3. Tear film
  4. Lids
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2
Q

What are the 4 diffrent complications of GP?

A
  1. Hypoxia
  2. Drying
  3. Mechanical
  4. Toxic / hypersensitivity
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3
Q

What are the 3 consequences of Hypoxia?

A
  1. Oedma
  2. Polymegetheism
  3. Neovascularisation
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4
Q

What is endothelial polymegthism and what is it caused by in relation to rgps?

A
  • Structural damage/ change of shape and size of endothelial cells
  • Caused by long term hypoxia
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5
Q

What are three associations for corneal neovasc?

A
  • Poor lens fit
  • Chronic irritation
  • Poor tear exchange
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6
Q

What causes vascularised Limbal keratitis? + what type of reaction can it lead to?

A

not enough lubrication and low edge lift which causes chronic induced irritation—> leads to an inflammatory reaction

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7
Q

What are signs of vascularised Limbal keratitis?

A

Corneal nodule called Pseudopterygium= coalesced localised superficial staining and stromal vascularisation along side it

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8
Q

What causes 3 and 9 o clock staining?

A

Mechanical/ drying, impression from lens edge

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9
Q

What are causes of 3 and 9 o clock staining (there are 8)?

A
  • Poor or incomplete blinking
  • Poor tear film
  • Large eye (wide palpebral aperture)
  • RGP material
  • Excessive edge clearance
  • Edges to thick
  • TD too big
  • TD too small
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10
Q

What are eight solutions to 3 and 9 o clock staining?

A
  • Break from lens wear
  • Correct blinking (blinking training)
  • change care regime, ocular lubricants
  • Refit with different material
  • Refit with a soft cl
  • Refit with lid attachment design
  • Different TD
  • Different peripheral design
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11
Q

What are seven signs which mechanical issues with RGPs can causes?

A
  • Corneal shape changes
  • Lens binding
  • Dimple staining
  • Foreign body tracks
  • Ptosis
  • Contact lens associated palpebral changes
  • 3 and 9 o clock staining
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12
Q

What technique is good for monitoring and measuring corneal changes?

A

Corneal topography

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13
Q

Describe Fischer-Schweitzer pattern? + what it indicates?

A
  • RARE - Poly mosaic wrinkling of bowman’s membrane, localised or cover whole cornea
  • will disappear on lens removal
  • stress indicator!!
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14
Q

Which condition out of Fischer-sweitzer or epithelial wrinkling will a px feel pain?

A

Epithelial wrinkling

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15
Q

What is epithelial wrinkling?

A

Small lines or furrows at any angle and it effects vision, Scl associated

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16
Q

If a px is showing signs of hypoxia and they have a small lens movement and low Dk?

A

Alter lens fit to increase mobility and cease wear temporarily

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17
Q

What is dimple staining ?

A

Small bubbles that mechanically compress and cause indentations in the epithelium and is caused

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18
Q

What is foreign body tracks?

A

Linear staining indicating the path taken by FB

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19
Q

How would you manage foreign body tracks?

A
  • Assess depth and extent
  • Remove lens for couple days
  • address cause
  • maybe replace the lens
  • may need to address cleaning regime
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20
Q

What is thought to be the cause of Ptosis in contact lens wearers?

A

stress due to removing the lens there is pressure put on the levator muscle through pulling on the eyelid and over time this begins to weaken it causing Ptosis

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21
Q

Where is a mechanically caused CLAPC associated with rgps? (Papillae)

A

Towards lash margin

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22
Q

What causes CLAPC due to proteins?

A

Build up of protein deposits which denature and leads to an Ige mediated inflammatory response which leads to pappliae to develop

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23
Q

What is the management of clapc?

A
  • Stop lens wear for couple weeks
  • advise them to use lubricating drops x3 a day
  • refit
  • discuss protein removable tablets
  • more frequent replacement
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24
Q

What is solution toxicity reaction ?

A

Px responds to preservative in solution which leads to localised epithelial reaction, conjunctiva hyperaemia and burning sensation

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25
Q

What are the four types of RGP complications?

A
  • Hypoxia
  • Drying
  • Mechanical
  • Toxic/hypersensitivity
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26
Q

What are three ways corneal oedema be caused?

A
  1. ill fitting PMMA lenses
  2. Low Dk
  3. tight fitting lenses due to restricted tear exchange
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27
Q

How can hypoxia effected the cornea and stroma? + effects on vision

A
  • Oedema of stroma –> contrast + light scatter
  • corneal clouding
  • corneal steepening —> myopic shift (EXTREME CASE)
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28
Q

How is corneal oedema caused?

A
  • CLs restricts O2creates hypoxic environment
  • Epithelium begins to respire anaerobically to conserve energy producing lactate
  • Lactate conc increases & moves into stroma
  • Endothelial pump cannot remove water from stroma at same rate it is entering stroma
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29
Q

What three signs you would see from corneal odema?

A

Striae, fold, haze

30
Q

What are striae? and what cases it?

A
  • fine verticals lines in posterior stroma
  • increases as oedema increases
  • caused by fluid separation of collagen fibrils
31
Q

What are folds?

A

Buckling of the stroma with depressed grooves and raised ridges

32
Q

What is haze of the cornea?

A

Milky appearance caused by gross separation of collagen fibres

33
Q

is corneal oedema a long term or short term issue?

A

long term

34
Q

what can long term endothelial polymegethism lead to?

A

corneal exhaustion syndrome–> problems for future surgery

35
Q

what slit lamp technique do you use to examine endothelial cells in endothelial polymegethism?

A

specular reflection

36
Q

is polymegethism curable?

A

no

37
Q

where is 3 and 9 o clock staining normally located?

A

nasal and temporal

38
Q

what is dellen? + what is is associated with?

A

small area of cornea that dries out that leads to thinning as it is exposed + associated with 3 and 9 o clock staining

39
Q

what may occur of you leave 3 & 9 o clock staining untreated?

A

vessel encroachment + opacification of tissue

40
Q

what would you do to assess what has caused 9 and 3 o clock staining?

A
  • assess tear film
  • assess fit of the lens

you would then adjust the management accordingly

40
Q

what would you do to assess what has caused 9 and 3 o clock staining?

A
  • assess tear film
  • assess fit of the lens

you would then adjust the management accordingly

41
Q

what are 7 signs of mechanical issues?

A
  • corneal shape changes
  • lens binding
  • dimple staining
  • FB tracks
  • ptosis
  • contact lens associated palpebral changes
  • 3 and 9 o clock staining
42
Q

apart from mechanical cause, what is another cause of contact lens associated palpebral changes?

A

allergic

43
Q

using corneal topography, what do red areas indicate?

A

steeper cornea

44
Q

can PMMA cause corneal warpage (irregular shaped cornea)?

A

yes- no o2 due to PMMA= corneal oedema = more prevalent warpage

45
Q

what will the px experience due to corneal warpage?

A

distortion in vision

46
Q

how would you monitor corneal warpage?

A

corneal topography

47
Q

What is a disadvantage of keratometry?

A

it only assess central cornea and cannot asssess periphery

48
Q

how would you manage corneal warpage?

A
  • cease lens wear
  • wait until corneal oedema settled (couple weeks)
  • then consider rx stability
49
Q

what kind of surgery can be contraindicated for someone with an irregular cornea?

A

refractive surgery

50
Q

if you see fischer-schweitzer pattern, what should you do?

A

as it dissapears on removal it is not and issue BUT big indicator that the RGP is not appropriate (due to fit)

51
Q

how do you differentially diagnose between epithelial wrinkling and fischer-schweitzer pattern?

A

epithelial wrinkling is v painful, scl associated, vision affected

52
Q

what is lens binding?

A
  • immobile and decentred which due to eyelid pressure causes indenting of cornea from lens edge –> leads to suction effect + hard to remove lens
53
Q

what eye condition can be noted with lens binding?

A

superficial punctate keratitis

54
Q

how would you be able to tell if someone has lens binding?

A

indentation staining on removal

55
Q

what is at an increased risk due to lens binding (think- immobile decentred bound lens on the cornea)?

A

HYPOXIA

56
Q

how do you manage lens binding?

A
  • re-fit lens for increase mobility (wait a little while before doing Ks incase cornea changes shape)
  • cease wear temp
57
Q

what can dimple staining indicate?

A

poor lens fit between cornea and lens (can occur with flat and steep fit lens)

58
Q

would dimple staining in centre of cornea (rather than peripheral) would be due to a flat or steep fit RGP?

A

steep- if a v steep fit lens they will have a centre air bubble which squashed cornea

59
Q

how would dimple staining due to a flat fitting RGP lens present?

A

peripherally

60
Q

how is dimple staining managed?

A
  • remove lens
  • modify fit
61
Q

can you get dimple veil staining in soft lenses?

A

yes - due to air bubbles

62
Q

what symptoms may you see with someone with foreign body track?

A
  • lacrimation
  • discomfort
63
Q

what must you check when you suspect contact lens-related ptosis?

A

neurological causes

64
Q

how do you manage contact lens related ptosis?

A
  • exclude neurological cause
  • could try soft cl
  • cease lens wear totally maybe
65
Q

what are two ways a mechanical CLAPC can be caused by in relation to lens fit?

A
  • excessive lens movement from loose lens
  • good lens fit but edge lift too larger
66
Q

is CLAPC due to protein deposits more prevelant in RGP or Soft cl wearers and why?

A

rgp because they are generally kept longer = more time for protein deposits to accumulate

67
Q

where is CLAPC due to protein deposits on the everted lid found?

A

near the fold of everted lid

68
Q

what sx would a px with toxicity reaction experience?

A

burning

69
Q

what is the management for solution toxicity reaction?

A
  • cease lens wear
  • lubricant drops
  • review in 3-4 days
  • resume lens + address cause accordingly
70
Q

what are two causes of solution toxicity reaction?

A
  • reaction to preservatives
  • peroxide in eye from hydrogen peroxide solution
71
Q

is CLIP reversible?

A

YES!!

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