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Contact lenses year 3 > Contact lens and dry eye management > Flashcards

Contact lens and dry eye management Flashcards

1
Q

what is the incidence of dry eye in contact lens wearers

A

52.7%

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2
Q

what is the incidence of dry eye in the general population

A

14-33%

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3
Q

what time of day do contact lens wearers tend to get dry eyes

A

at the end of the day with soft contact lenses when their lenses have dried out

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4
Q

what structure of the eye does a contact lens divide, and what are these divided structures called

A
  • it divides the pre corneal tear film into the:

Prelens tear film (PLTF) and the post-lens tear film (PoLTF)

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5
Q

what is the pre lens tear film (PLTF) associated with

A

comfort-needs to protect lens from drying or getting deposits

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6
Q

what is the post lens tear film associated with

A

lens fit and movement

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7
Q

what will happen to which ocular structure if a contact lens dries out in the eye

A

it will scratch the cornea when blinking

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8
Q

when should you assess the tear film and what should you see in slit lamp

A
  • assess the tear film before and after putting the lens in

- on slit lamp, do specular reflection to check the tear film for purkinje image 1 with the lens in

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9
Q

which layer of the tear film does the contact lens sit on

A

the aqueous layer of the teat film

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10
Q

Lipid layer __________ and

sometimes _________ in PLTF

A

Lipid layer thinner and

sometimes absent in PLTF

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11
Q

as a result of a thinner or sometimes non existent lipid layer in the pre lens tear film, what happens to RGP and soft contact lenses

A
  • RGP - lipid layer is almost non-existent therefore get deposits on the lens as theres no tears to wash them away
  • SCL - get spots on the lens
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12
Q

what does the post lens tear film help with, and what function is important for a post lens tear film and why

A 
- helps posterior lens
lubrication 
- Tears must not
be static, tear exchange is
important for removal of tear
debris and metabolic by products
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13
Q

which type of lens does RGP lenses have more tear mixing than

A

hydrogel lenses

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14
Q

list 4 effects that contact lenses have on the tear film

A
  • Changes in tear production?
  • Tear film instability and evaporation
    – Related to lipid layer and initial tear film thickness
    – Visual acuity may fluctuate
  • Effect on tear film mucins, electrolytes and increased osmolarity
    – Reduced mucin, increased friction
    – Higher osmolarity associated with dry eyes
  • blinking
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15
Q

explain the 2 effects of tear film instability caused by contact lens wear

A
  • Related to lipid layer and initial tear film thickness
    = the lens dehydrates and dry sports are formed on the lens
  • Visual acuity may fluctuate
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16
Q

as well as the visual acuity which may fluctuate, what other acuity is also affected by contact lens use

A

contrast sensitivity also declines whilst wearing the contact lenses

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17
Q

explain the 2 effects on tear film mucins, electrolytes and

increased osmolarity caused by contact lens wear

A

– Reduced mucin = increased friction

– Higher osmolarity associated with dry eyes, as this reflects the concentration of proteins and electrolytes

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18
Q

what does a higher osmolarity in the tears reflect

A

the concentration of proteins and electrolytes in the tears

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19
Q

how is the effect of contact lens on the tear film related to blinking

A

initially the patient blinks a lot (reflex tearing), but afterwards they start to blink less, however this doesn’t stop the lens from dehydrating

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20
Q

reflex tearing doesn’t….

A

stop the lens from dehydrating

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21
Q

list the 5 different factors of the multifactorial condition of contact lens related dry eye

A
  • patient characteristics
  • lens material
  • environment
  • lens fitting
  • lens solution
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22
Q

name 2 clinical ocular signs of contact lens related dry eye (CLDE)

A
  • Lid wiper epitheliopathy (LWE)

- Lid parallel conjunctival folds (LIPCOF)

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23
Q

where is and what is the job of the lid wiper

A
  • the portion of the marginal conjunctiva of the upper eyelid
  • its job is to wipe the ocular surface during blinking
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24
Q

what happens during lid wiper epitheliopathy and what is the consequence

A
  • The dry anterior surface of lens rubs against the underside
    of eyelids, particularly the area near the eyelid margin
  • Tear film thickness too thin to separate ocular surface
    and lid wiper

As a consequence, this causes an alteration in epithelium due to friction

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25
Q

what may you do to look for lid wiper epitheliopathy

A

Staining:

  • May stain with NaFl, but more so with lissamine green
  • Will need to evert lids
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26
Q

which eyelids is the staining found from lid wiper epitheliopathy most commonly found

A

Usually staining on upper lids, but can also affect lower lid

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27
Q

although lid wiper epitheliopathy may be asymptomatic, name 3 symptoms that can occur

A
  • May have increased lens awareness
  • Irritation on blinking
  • Reduced wear time

as the patient blinks, they will feel the lens rubbing as the pre lens tear film is not thick enough

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28
Q

list the 4 signs of lid parallel conjunctival folds (LIPCOF)

A
  • Breakdown/decrease in elastic fibres in the loose conjunctiva
  • Conjunctival looseness
  • Ageing or mechanical forces
    between conjunctiva and lower lid
  • Tear deficiency and inflammation of the conjunctiva
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29
Q

what happens as a result of ageing or mechanical forces

between conjunctiva and lower lid and what will a patient who has this also have

A
  • it is conjunctival looseness and folding of the conjunctiva
  • if the patient has this, then they will have lid wiper epitheliopathy
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30
Q

what is lid parallel conjunctival folds (LIPCOF) graded according to

A

the number and the height of the folds

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31
Q

describe grade 1 of lid parallel conjunctiva folds (LIPCOF)

A

one permanent and clear parallel fold

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32
Q

describe grade 2 of lid parallel conjunctiva folds (LIPCOF)

A

two permanent and clear parallel folds which are normally less than 0.2mm

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33
Q

describe grade 3 of lid parallel conjunctiva folds (LIPCOF)

A

more than 2 permanent and clear parallel folds normally > 0.2mm

34
Q

list 3 things that can be done to manage lid parallel conjunctiva folds (LIPCOF)

A
  • Change lens type or wearing schedule
  • Manage any tear quality issues
  • Consider rewetting drops
35
Q

what is the condition called for patients who have a lifestyle of prolonged computer, tablet or phone use, which can cause dry eyes

A

computer vision syndrome (CVS)

36
Q

list 5 symptoms of computer vision syndrome (CVS)

A

eye discomfort and visual problems including:

  • Dry eyes…related to blinking
  • Eyestrain
  • Headaches
  • Blurred vision
  • Neck and shoulder pain
37
Q

what is value for resting blink rate

A

12x a minute

38
Q

when may blink rate change depending on

A
  • activity, on cognitive or emotional function

- some diseases and medication

39
Q

what can cause a blink rate to increase

A

when engaged in conversation

40
Q

what can cause blink rate to decrease and to what value can this decrease down to

A

when focussing on a specific visual task

can drop to an average of 4.5x per min when reading

41
Q

what diseases can blink rate be affected by

A
  • parkinson’s
    and
  • schizophrenia
42
Q

what does a reduced blink rate mean for the tear film

A

it is replenished less frequently and evaporates quicker causing ocular discomfort

43
Q

what is computer vision syndrome associated with

A

a reduced blink rate

44
Q

by how much does a patient with computer vision syndrome blink less

A

by 60% less blinking

45
Q

as well as reduced blink rate in computer vision syndrome, what is also reduced

A

the completeness of a blink

46
Q

what is described as a full/complete blink

A

when the top lid touches the bottom lid

47
Q

what is increased with computer vision syndrome

A

increased teat break up time

48
Q

list 5 things that can be done for managing the symptoms of dry eye

A
  • Lens changes
  • Changes to environment
  • Eye drops: lubricants, lipid specific products
  • Lid hygiene: lid cleansing, heat
  • Diet
49
Q

what should you start off with in order to diagnose/manage your patient with contact lens related dry eye

A

a thorough history and symptoms

50
Q

list 3 things/questions a thorough history and symptoms should consist of

A
  • Use of dry eye questionnaires
  • Is wear time all comfortable wear time?
  • When do symptoms begin/end?
    How often do symptoms occur?
    Are they present even without
    the lens? (work out if its the lens or the eye thats the cause)
51
Q

list 7 ideal characteristics of a contact lens which has the minimum effect of causing dry eye

A
  • Good hydration
  • Low surface friction
  • High wettability
  • Low levels of deposition
  • DK/t
  • Fit and lens design
  • Replacement frequency
52
Q

how do you check that a lens has a low surface friction

A

it is measured by the coefficient or friction

the lens should be smooth when blinking

53
Q

what do you want to avoid with a lens design in order to avoid dry eyes

A

don’t want the lens to be too steep as we don’t want the edges to pinch in

54
Q

what 7 causative factors requires a management of the patients environment as it increases contact lens discomfort

A
  • Low humidity
  • Increased airflow
  • Computer use
  • Temperature
  • Allergies such as hay fever, pollen, dust and pets
  • Air pollution
  • Smoking, which can build up on reusable lenses
55
Q

list the 5 ideal features of eye drops

A
  • Immediate relief
  • Prolonged effect
  • Non-toxic
  • Doesn’t blur vision
  • Inexpensive
56
Q

what 3 things must you check before prescribing eye drops to a contact lens dry eye patient

A 
- Check compatibility with
contact lenses
- Preservative free ?
- Ensure no other cause of
symptoms…e.g. poor lens
fit
57
Q

what is viscosity

A

the measurement of a fluid’s internal resistance to flow

58
Q

what does a higher artificial teat viscosity means for tear retention time

A

tear retention time is increased and might help protect the ocular surface

59
Q

what are the 3 aims of viscosity agents

A
  • Aim is to try and increase
    retention time
  • Reduce friction
  • Soothe irritated membranes
60
Q

what type of ocular lubricants is reserved for more severe dry eye

A

gels and ointments

61
Q

what is associated with the use of ointments

A

blurred vision

62
Q

what are the 3 rules of lubricating ointments

A
  • avoid with CL wearers
  • for use at night
  • note recent product recall
63
Q

Increased ___________ and
____________ indicates
dry eye

A

Increased osmolarity and
inflammation indicates
dry eye

64
Q

Some say osmolarity

which ________ osmolarity of normal tears is ______, others suggest ___________ artificial tears are _______

A

Some say osmolarity which mimics osmolarity of normal tears is ideal, others suggest hypoosmolar artificial tears
are better

65
Q

what do hypotonic artificial tears do to the tears

A

reduces the osmolarity of the tears and also reduces salt levels

66
Q

Products which mimic the _________ composition of _______ tears are available

A

Products which mimic the
electrolyte composition of natural
tears are available

67
Q

which 2 electrolytes seem to be important for tears

A
  • potassium

- bicarbonate

68
Q

what is electrolyte balance in the tears important for

A

the maintenance of conjunctival goblet cells

69
Q

what is the property of conjunctival goblet cells

A

to act as a natural lubricant

70
Q

what 4 things must you do before issuing someone with lubricating eye drops

A
  • Spend time discussing condition with patient and explaining management plan
  • Demonstrate use (do not just issue product samples)
  • Instruct how often patient should use drops
  • Book a follow-up/review: e.g. after a month, to make sure what we have prescribed works
71
Q

what are the instructions for maintaining lid hygiene

A
  • Diluted baby shampoo, sodium bicarbonate solution or lid cleaning solution with a cotton bud
  • Clean lid margins (not beyond the mucocutaneous junction)
  • 2x daily; reduce to 1x daily as condition improves
  • Use firm pressure with cotton bud to express glands
  • Warm compresses to loosen collarettes and crusts
  • Avoid use of cosmetics, especially eye liner and mascara
72
Q

what three things can be used for lid hygiene

A
  • diluted baby shampoo
  • sodium bicarbonate solution
  • lid cleaning solution
73
Q

what is the aim of warm compress therapy

A

Aim of therapy is to melt the meibum to allow it to be expressed and to prevent obstruction of the terminal ducts

74
Q

what should be monitored when doing warm compresses

A

temperature

you don’t want to burn the eyes, you just want the temperature to be warm enough to melt the meibum within the glands

75
Q

name a heating device that can be used as a warm compress therapy

A

the Eyebag - which is a silk and cotton device which is filled with flaxseed (linseed)

76
Q

how long does a Eyebag take to heat up and how does the heat last for

A
  • 30-40 seconds to heat

- 10 minutes heat is retained

77
Q

what is required in our diet that our body cannot make itself

A

essential fatty acids

which have to come from our diet

78
Q

what are essential fatty acids understood to enhance

A

the lipid layer of our tear film, reducing evaporation

79
Q

name 2 essential fatty acids and what each of their properties are and hence the implications this may have

A

Omega 3 – anti-inflammatory properties
Omega 6 - pro-inflammatory properties?

Too much consumption of omega 6 may negate the effects of omega 3

80
Q

what 2 types of liquid will generally dehydrate the body

A

caffeine and alcohol

81
Q

why is drinking water a weak management plan for dry eyes

A

because there is not a big enough study to prove that it’s effects work

82
Q

list all the 7 possible management routes that can be taken to treat dry eyes

A
  • environment changes
  • eye drops/gels/ointments
  • osmolarity agents
  • lid hygiene/scrubs
  • warm compresses/heating devices
  • essential fatty acids in the diet
  • drinking water?

Contact lenses year 3 (15 decks)

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