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Contact Lenses 3 > unit 2 cont.. (quiz 3) > Flashcards

unit 2 cont.. (quiz 3) Flashcards

1
Q

what is lens surface crazing

A

-surface cracks in the GP
-appear as multple cracks or a mesh-like lattice

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2
Q

symptoms of lens surface crazing

A

poor or fluctuating vision

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3
Q

causes of lens surface crazing

A

-matierial related problems
–weakness in the structure of the lens material or surface stress induced lens manufacture
-patient use of alcohol based cleaners

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4
Q

treatment for lens surface crazing

A

-it is not possible to remove the surface cracks
-GP lenses must be replaced

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5
Q

dimple veiling

A

-trapped air bubbles underneath the GP lens -> causes pits to form in the cornea
-Not true staining
-DO NOT move with the tear film when blinking
-appear as bright green dots
-once CL is moved it goes away

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6
Q

symptoms of dimple veiling

A

sometimes reduced vision
-reduces the corneas optics

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7
Q

causes of dimple veiling

A

steep fitting GP CL

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8
Q

treatment for dimple veiling

A

flatten the lens
-flatten the BC or decrease diameter

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9
Q

why does wettability matter?

A
  • a non-wet surface allows lens depostis to attach to the lens easily
    -A non-wet surface decreases a pxs VA
    -a non-wet surface increases friction with the inner eyelid which can cause discomfort
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10
Q

how does poor surface wettability appear?

A

-appears as “beads” of liquid on the lens surface
-can also have a filmy or deposit like apperance

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11
Q

Causes of poor wettability

A

-matieral or manufacturing problem of the GP
-Lenses may have a waxy residue from the production proccess
-px related issues..
-improper cleaning
-dry eye disease
-use of lanolin-containing soap/lotion

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12
Q

treatment options for poor wettability for CL issues

A

-pre soak the lens overnight prior to dispense
-use a solvent followed by reconditioning with wetting solution
-plasma treatment to remove waxy residue
-refit to a diff lens matieral

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13
Q

treatment causes for poor wettability in respect to px cause

A

-make sure the px learns proper technique for care including rubbing lenses and using the solution properly
-avoid lanolin creams and soap prior to handling lens
-treat dry eye desease

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14
Q

5 layers of cornea

A

-epithelium
-bowmans layer
-stroma
-descemets membrane
-endothelium

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15
Q

how corneal infection develops

A
  1. corneal epithelium is damaged
  2. microbes invade cornea
  3. immune response activated
  4. cornea becomes inflamed
  5. microbes penetrate deeper and cause scaring
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16
Q

The avascular cornea

A

-the cornea is avascular (without blood vessels)
-when a px wears CLs, oxygen flow to the cornea is reduced
-can lead to cornea hypoxia (lack of oxygen to cornea)

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17
Q

corneal hypoxia

A

-primarily caused by CL wear
-causes a series of events to occur which impacts corneal health

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18
Q

how to reduce risk of corneal hypoxia

A

-using contact lens materials with high oxygen transmisibility (DK/t)
-avoid over wear of extended wear of CLs

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19
Q

corneal neovasularization

A

-happens when the cornea continues to receive limited oxygen, this can cause new blood vessels to grow from the conjunctiva into the cornea

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20
Q

symptoms of corneal neovascularization

A

-sometimes no symptoms (if mild)
-cloudy/hazy vision (if severe)
-from damage to the clear corneal tissue (loss of transparency)
-from blood veseels blocking or bending light entering the eyes

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21
Q

treatment options for neovascularization

A

-refit to a more breathable lens
-discontinue CL wear until resolved
-px education

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22
Q

Limbal vessel encroachment

A

-Precursor or ‘warning sign’ of future neovascularization
-increase in limbal vasculature and extension into the hazy zone of the limbus

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23
Q

what is corneal infiltrates

A

-inflammatory cells in the corneal tissue
-grey or white in apperance
-Indicates that white blood cells have migrated to the stroma

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24
Q

symptoms of corneal infiltrates

A

-sometimes asymptomatic
-irritated, watery eyes

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25
Q

types of corneal infiltrates

A
  1. Infectious -> Bacteria, viruses
  2. Sterile-> means NOT infectious
    -CL wear is the most common cause of sterile infiltrates
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26
Q

what is a corneal ulcer

A

-an open sore in the outer layer of the cornea
-most commonly caused by an infection
-other causes .. severe dry eyes, abrasions or burns
-ulcer is best visualized with fluorescein (appear green)

27
Q

apperance of a corneal ulcer

A

white spot or mark on the cornea that stains with fluroscien

28
Q

Main risk factor of corneal ulcer

A

CL wear is the #1 risk factor
-in contact lens wearers, ulcers can cause permanent vision loss
-treat quickly to avoid corneal staining
-URGENT REFERRAL

29
Q

difference between infiltrate and ulcer

A

-Infiltrate= white blood cells in corneal stroma, hazy/white with no fluroscein stain
-ulcer= loss of stromal tissue, causing a divot, can also be hazy but ALWAYS stains with fluroscein

30
Q

can infiltrates sometimes later turn into an ulcer?

A

yes, but not always

31
Q

do infiltrates and ulcers represent a sign of another disease?

A

yes, they can exist as their own conditino but also represent a sign of another disease state such as
-contact lens specific conditions
-keratits

32
Q

CLARE - contact lens acute red eye

A

-inflammation of the outer surface of the eye
-only occurs in pxs wearing CLs (most common from extended wear)
-inflammation results from lack of oxygen, contamination of the CL with bacteria or protein deposits
NOT A TRUE CORNEAL INFECTION

33
Q

what do you see when someone has CLARE

A

-corneal infiltrates
-conjuctival redness

34
Q

signs of CLARE

A

-360 degrees red eye, often worse near the limbus
-infiltrates, often multiple
-ususally unilateral
-NO staining w/ fluroscein

35
Q

symptoms of CLARE

A

-Typically in extended wear CL pxs who wake up with red and painful eye (after sleeping in CL)
-watery
-irritated

36
Q

treatment of CLARE

A

-discontinue CL wear until resolved
-Refer - might need medicated eye gtts like a steroid
-prescribe new CLs: daily, or lenses with higher Dk/t
-improve px habits

37
Q

CLPU - contact lens peripheral ulcer

A

-inflammatory condition causing loss of epithelial and stromal tissue
-a sterial ulcer (NOT INFECTIOUS)

38
Q

apperance of CLPU

A

-infiltrate with fluroscein stain in peripheral location
-small
-circular
-well defined

39
Q

how to reduce bacterial sources to prevent reocurrence

A

-lid hygiene
-increase CL replacement
-chance care system/solution

40
Q

what happens when you discontinue CL wear when you have CLPU

A

typically heals is 3-4 days
-faint scar may persist for several months

41
Q

what is Keratits

A

-inflammation of the cornea
-may or may not be associated with an infection
-generally affects one eye
-all cases require an urgent referral to prevent permanent vision loss

42
Q

2 types of keratits

A

-Non infectious keratits
-infectious keratits

43
Q

Types of noninfectious keratits

A
  1. Toxic keratits
  2. Vascularized limbal keratits
    -caused by an eye injury (scratch or damage to corneal surface)
44
Q

types of infectious keratits

A
  1. bacterial keratits
  2. fungal keratitis
  3. acanthamoeba keratits
  4. viral keratitis
45
Q

symptom of keratitis

A
  • red eye
    -eye pain
    -blurry vision
    -watery eyes
46
Q

Keratitis signs

A

-Possible infiltrate
-possible ulcer

47
Q

toxic keratitis

A

-direct contact of hydrogen peroxide cleaning solutions with the eye
-appear as small dot-like opacities on the cornea that stain w/ fluroscein

48
Q

treatment for toxic keratitis

A

-irrigate eyes
-artifical tears
-no CLs until resolved
-px education

49
Q

Vascularixed limbal keratitis (VLK)

A

-rare complication of GP lens wear
-most commonly from extended wear of GP lenses which damage the limbal stem cells
-chronic 3 and 9 staining can lead to the development of VLK

50
Q

3 clinical signs associated with VLK

A
  1. severe 3 and 9 staining
  2. raised, inflamed, semi-opaque epithelial lesion
  3. localized vascularization of conrea
51
Q

symptoms of VLK

A

-lens awareness
-localized ocular pain
-red eye w/ elevated corneal mass upon self inspection in mirror

52
Q

treatment of VLK

A

-ATs
-evaluate lens and fit
-evaluate lens diameter
(consider smaller diameter to decrease mechanical irritation to limbus and cornea)

53
Q

CL related risk factors for developing infectious keratits

A

-sleeping in CLs
-swimming/showering in CLs
-poor CL hygeine habits
-improper CL solution use
-not disposing of CLs as directed

54
Q

How common is infectious keratitis

A

-approx 2-20 cases per 10,000 contact lens wearers each year
-90% of cases were in soft CL
-10% of cases were in GP

55
Q

Bacterial keratitis

A

-most common form of keratitis (90% of cases)
-develops rapidly (2-3 days)
-In CL wearers, bacterial keratitis is most commonly caused by a bacterial called pseudomonas aeruginosa
-round/oval white lesions

56
Q

what do pseudomonas do

A

easily attach to the surface of CLs and survive in ocular enviroments

57
Q

signs and symptoms of bacterial keratitis

A

-eye pain
-blurry vision
-red eye
-mucopurulent discharge
-eyelid swelling
-hazy cornea (infiltrate)
-hypopyon
-anteriror chamber reaction

58
Q

treatment of bacterial keratitis

A

-emergency referral
-antibiotic eye drops (depending on severity. may use gtts as frequently as every 30mins)
-possibly oral antibiotics
-no CL wear until resolved
-can use eye gtts to control pain (cycloplegic)

59
Q

viral keratitis

A

-history of cold sores
-dendritic ulcer (branching epithelial defect)

60
Q

fungal keratitis

A

-trauma, vegetative/outdoor
-infiltrate with feathery edges
-grey-white lesion

61
Q

protozoal keratitis AKA acanthamoeba

A

-contact lenses (poor hygeine)
-ring shaped infiltrate

62
Q

how thick is the cornea?

A

540um

63
Q

corneal anatomy

A

-no blood vessels to supply nutrients or protect against infection
-Nutrients via diffusion
~tear film/air
~aqueous humor
~closed eyelids
-robust limbal blood supply
-transparent
~nonvascular
~dehydrated

Contact Lenses 3 (5 decks)

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