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OD3 (S1&2) > CLM - Paediatric Contact Lens Fitting - Week 11 > Flashcards

CLM - Paediatric Contact Lens Fitting - Week 11 Flashcards

1
Q

List four indications for paediatric contact lens fitting.

A

Infantile aphakia
High myopia (uni/bilateral)
Hyigh hyperopia (uni/bilateral)
Ocular trauma

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2
Q

What percentage of world childhood blindness does infantile cataract account for?

A

10%

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3
Q

What percentage of infantile cataract cases are bilateral? What percentage are idiopathic?

A

65%
?50% idiopathic

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4
Q

Is uni- or bilateral infantile cataract more common? Is it generally hereditary? What is it associated with?

A

Bilateral is more commonly hereditary or associated with systemic disorders

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5
Q

How does a denser cataract affect HVID in infantile cataract? what about K values?

A

Smaller HVID
Steeper K

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6
Q

What is unilateral infantile cataract often associated with? Give three examples.

A

Ocular anomalies
i.e. microphthalmia, aniridia, PHPV

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7
Q

What demographic of infants is infantile cataract associated with (2)?

A

Prematurity
Low birth weight

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8
Q

What is the most common cause of acquired infantile cataract? What is it more likely with?

A

Blunt or penetrating trauma
-more likely with penetrating

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9
Q

Is visual prognosis better or worse with uni- or bilateral infantile cataract? Explain why (2).

A

Better with bilateral cataracts
Amblyopia is inevitable with unilateral, common with bilateral

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10
Q

What is more critical with unilateral infantile cataract vs bilateral?

A

Age of treatment

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11
Q

What is the best treatment for amblyopia after infantile cataracts?

A

Patching

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12
Q

What is a treatment option for amblyopia following bilateral infantile cataract? Comment on effectiveness.

A

Refractive penalisation - no lens in the better eye
Doesnt always work

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13
Q

Is the incidence of strabismus higher in uni- or bilateral infantile cataract or the same?

A

More common in unilateral

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14
Q

What is generally considered once VA of the amblyopic eye is optimised (infantile cataract)?

A

Strabismus surgery

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15
Q

What is the treatment for infantile cataract? What does this increase the risk of and within what timeframe? What should be done immediately following treatment (2)? What is the best option? Comment the use of spectacles and IOLs for bilateral aphakia in infants.

A

Surgical removal ASAP
-extraction <1/12 increases the risk of glaucoma
Immediate visual rehabilitation after
-refractive correction
-any amblyopia therapy
Contact lenses the best option
Can do spectacles for bilateral aphakia
-use of IOLs in infants controversial

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16
Q

List 9 aspects of patient examination for infantile cataracts.

A

Discussion with the parents
Case history
-prematurity, other problems
Ocular alignment
Hand-held slit-lamp
Hand-held keratometry
Retinoscopy
HVID/lid anatomy
EUA

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17
Q

List three types of contact lenses for infantile aphakia.

A

Rigid lenses
Soft lenses
silicone elastomer lenses

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18
Q

Between soft and rigid contact lenses, which causes less mechanical irritation for infants?

A

Soft

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19
Q

Between soft and rigid contact lenses, which is more forgiving in terms of fitting for infants?

A

Soft

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20
Q

Between soft and rigid contact lenses, which is more easily rubbed out by infants?

A

Soft

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21
Q

What is a potnetial problem with hydrogel soft contact lenses in infants?

A

Low Dk/t causing corneal hypoxia

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22
Q

What does soft contact lens dehydration create the need for?

A

May need even higher BVP

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23
Q

Is lens insertion on infants easy or hard with soft contact lenses?

A

Very difficult

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24
Q

Can soft contact lenses for infantile aphakia be used for spherical as well as cyll errors?

A

Spherical only

25
Q

Are silicone elastomer lenses easy or difficult to insert on infants? Do they have a high or low Dk/t?

A

Easy
High Dk/t

26
Q

Do silicon elastomer lenses provide better or worse VA campared with soft lenses? Why is this so?

A

Better VA due to higher modulus

27
Q

Is the cost of silicon eleastomer lenses an advantage or disadvantage?

A

Disadvantage - theyre expensive

28
Q

Do silicon elastomer lenses have a long or short shelf life? Explain why.

A

Short due to lipid deposition

29
Q

Which of the three lens designs for infants is the best option? Explain why (3).

A

Rigid lenses
-easier handling
-less complications
-high Dk

30
Q

Can rigid lenses mask astigmatism in infants?

A

Yes

31
Q

Are rigid lenses more or less commonly rubbed out by infants? Is the lens being rubbed out very painful, or not very?

A

Less commonly rubbed out
-rubbing very painful for infants

32
Q

Is the initial discomfort of rigid lenses more or less of a problem for <6 year olds?

A

Less of a problem

33
Q

What are rigid lenses more prone to (2)?

A

Dust and foreign particles

34
Q

Are rigid lenses more or less forgiving with fit? Explain what this means.

A

Less forgiving
-more staining with ill fitting

35
Q

List fourt types of rigid lenses available for infants.

A

Corneal
Corneo-scleral
Mini-scleral
Scleral

36
Q

Are rigid lenses for infants mainly custom or stock?

A

Custom designed

37
Q

When is EUA done?

A

Only when absolutely necessary

38
Q

What is a problem with infant eyes when fitting for lenses?What does this mean for the lenses?

A

Rapid growth during the first 18 months
Frequent lens changes required

39
Q

Does the growth of the aphakic eye match the normal eye? Explain in terms of K, corneal diameter, and decrease in hyperopia.

A

Not equal
-faster increase in K
-decrease in corneal diamter
-faster decrease in hyperopia

40
Q

When does the greatest K increase occur in infants?

A

3/12

41
Q

When do infants reach adult K levels?

A

By 3 years

42
Q

What is the average Rx for an aphakic eye at 1/12? How does this change over the next year?

A

+30D
Average decrease of 4D during the first year

43
Q

How many peripheral curves do corneal or corneoscleral lenses have for infants?

A

At least 4

44
Q

What is the total diameter of corneal or corneoscleral lenses like for infants?

A

> HVID

45
Q

How is the BOZR generally selected for infants? What is the average?

A

If EUA, use keratometry
Otherwise select according to age
Average is 7mm

46
Q

Is the BOZR flatter or steeper with microphthalmia and prematurity?

A

Steeper

47
Q

Should infants be overcorrected? Explain.

A

Overcorrected in he plus direction and gradually decreased with age (for near)

48
Q

How many times would you expect to modify lens due to ocular growth in the first and second year for infants? What should you be weary of?

A

First - 3-4 times
Second - twice
Be weary of sudden marked change

49
Q

Troubleshoot the following in infants:
Large myopic shift (2)
Large hyperopic shit (1)
Loss of fixation (5)
Unstable lens (steep vs flat)

A

Large myopic shift
-growth spurt
-glaucoma
Large hyperopic shift
-retinal detachment
Loss of fication
-dense amblyopia
-lens in the wrong eyes
-acute pathology
-after-cataract
-lens deposits
Unstable lens
-steep fit ejects
-flat fit mislocates

50
Q

Can high myopia in infants be uni- or bilateral? What magnitude (give range)?

A

Both
-6 to -20

51
Q

What is the first choice for high myopia?

A

Rigid

52
Q

What is often seen with high myopia in infants?

A

Significant corneal cyl

53
Q

Can you use SiH lenses for most high myopic infants?

A

Yes

54
Q

Can high hyperopia in infants be uni- or bilateral? What magnitude (give range)?

A

Both
6 to 12

55
Q

What is the best option for high hyperopia in infants? Is overcorrection required? Explain why.

A

Rigid
Can accommodate - over-correction not required

56
Q

What is K often like with high hyperopia in infants?

A

Steep K

57
Q

What is the major cause of acquired cataract?

A

Ocular trauma

58
Q

Is ocular trauma more common in boys or grils?

A

Boys

59
Q

When are rigid lenses used for ocular truama in children (2)?

A

Corneal scarring and aphakia

OD3 (S1&2) (114 decks)

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