Week 8 - Cl Lenses in children

Question 1

Anatomical considerations

Answer 1

• Small palpebral aperture size (PAS)
• Strong orbicularis oculi muscle tone
• Decreased blink frequency
• Tear volume (low in neonates, 1 with age)
• Development of tear reflex (when is this?)
• Steep anterior corneal curvature
• Changing corneal shape & Rx

Question 2

Why bother with Cls in children?

Answer 2

• ^ field-of-view cf. spectacles
• Enhanced normal visual development
• Children are more tolerant of CLs than adults
• Better aqueous layer in the tear film

Question 3

Potential problems/obstacles

Answer 3

• Risk of corneal infection (other complications)
• Difficulty in lens handling
• Expense involved
• Parent counselling
• Communications with other relevant practitioner (S)
• CL intolerance
• Levels of motivation
- parents &/or family
- child if old enough
• Contraindications due to systemic or ocular conditions

Question 4

When would we use Cls for children?

Answer 4

• Aphakia, myopia, hyperopia, astigmatism, & anisometropia
• Accommodative esotropia
• Patching for amblyopia
• Bandage, photophobia, nystagmus, or albinism
• Cosmetic
• When spectacles are inappropriate/disliked (intensely)
• Craniofacial abnormalities
• Myopia control - will be covered in a separate lecture

Question 5

Refractive assessment for CLS:

Answer 5

• Retinoscopy
- static
- dynamic
• Cycloplegic assessment
• Auto-refraction
• Where possible, full refraction based on:
- level of comprehension
- age
- interaction with practitioner

Question 6

Keratometry in children:

Answer 6

• In non-traumatized corneas, it is possible to use age norms for corneal curvature as a starting point for CL fitting.
• The central corneal curvature of infants is usually steep:

• 47.00 D (7.18 mm) to 50.00 D (6.75 mm) in the first 1 to 2 months.
• By 3 to 4 years of age, the cornea flattens to between 43.00 D (7.85 mm) & 44.00 D (7.67 mm)
• Age 5 onwards may manage normal keratometry or topography.

Question 7

HVID and PAS/WID

Answer 7

• As normal with a ruler
• Patience and assistance from parents/carers may be required

Question 8

Refractive error

Answer 8

• Cycloplegic refraction essential
• Prescribe if >2.50 D Cyl @ 15 months, sooner if astigmatism is oblique or VA is reduced
• Significant spherical RX - what is significant?

Question 9

Refractive error - Aphakia

Answer 9

• Aphakia - congenital, surgical, trauma
• Note that contact lenses can be used from 3 weeks old for aphakia, these are usually placed by the surgeon to encourage normal visual development

• Contact lenses are the only option in unilateral aphakia - why?
• Good optical correction
• Significantly decrease distortion
• decrease image magnification
• Normal binocular development
• Easy to adjust Rx as required
• Better tolerated than spectacles

Question 10

Refractive error - Aphakia: Cls available

Answer 10

Rigid gas-permeable CLs (GP CLs)
Soft contact lenses (SCLs)

• Age: 6 weeks Suitable BVP: +34.00D
• Age: 6 months Suitable BVP: +28.00D
• Age: 12 months Suitable BVP: +24.00D

Question 11

Paediatric Amblyopia CL treatment:

Answer 11

• Opaque tint (black, occlusive)
• Monocular occlusion of the better eye
• Tolerated better than patching
• Better cosmetic effect
• Optical defocus with high plus power
• Quicker adaption with soft CL
• This could also be done for photophobia, nystagmus, or albinism

Question 12

Cosmetic cls used for:

Answer 12

• Albinism - also helps with symptoms
• Aniridia
• Microphthalmos
• Corneal scars/opacities
• Inoperable cataracts

Question 13

Type of CLs:

Answer 13

• SCLs (hydrogel CLs)
• Silicone hydrogel CLs (SiHy CLs)
• Rigid gas permeable (GP CLS)
• Hybrid CLs
• Scleral mini-scleral CLS

Question 14

Which type of CL to pick?

Answer 14

• Nature of the ocular problem i.e. Eyes with ocular albinism require darker therapeutic tints, aniridia may need an artificial pupil
• RX
• O2 transmission
• Required wearing schedule (part-time or full-time, DW or EW)
• Cost

Question 15

Extended wear with children:

Answer 15

• EW carries a significant risk of complications, & the child should therefore be monitored carefully, especially for asymptomatic changes such as neovascularization.
• Another disadvantage of an EW schedule is that the patient does not become as proficient in handling their CLs.
• It is advisable to have spare set of CLs available in case of CL loss or breakage, especially in young infants with high refractive errors.

BUT eliminates the need for daily CL insertion & removal, regular handling of the CLs, & CL care procedures

Question 16

Hydrogel lenses:

Answer 16

• Good initial comfort
• Easy to fit
• Stock & custom designs readily available
• Fewer deposit-related problems with low water materials
• Some physiological concerns due to low Dk/t
• Low water materials -> 1 rigidity
• Tints & UV blocking available

Question 17

Silicone Hydrogel

Answer 17

• -> high oxygen transmission
• Ease of handling
• Ease of lens replacement
• Parameter range is as category matures
• Good extended wear capability

Question 18

RGPs

Answer 18

• Physiological advantages (comparable with SiHY CLs)
• Handle well
• Ease of care & maintenance
• Custom fitting requires skill & knowledge

• Tints or handling tints available
• UV blocker available in some materials
• CL TDs: 8.0 to 10.5 mm
• Risk of mislocation & dislodgement from the eye

Question 19

Hybrids

Answer 19

• Astigmatism, irregular corneas, & keratoconus
• Intolerance of GP CLs
• High ametropias
• Absence of limbal impingement
• Patient comfort

Question 20

Scleral CLs

Answer 20

• Required in a small % of paediatric patients
• More difficult to insert & remove
• May experience some discomfort
• Minimal lens loss or accidental removal

Question 21

CL insertion

Answer 21

• A challenge!!
• In the case of infants or very young children, it is sometimes necessary for one or two people to hold the child’s arms & shoulders down, while another person pulls the lids apart & inserts the CL.
• It is therefore a good idea to involve both parents where possible.
• The child can also be wrapped in a towel to restrain the limbs
• Or when they are asleep!

•Try to have the child involved as early as possible, this can be from the age of 5/6

Question 22

CL Removal

Answer 22

• Teaching child/parents
• Breaking the ‘suction’ (letting air under the CL)
• Using the lid margins
• Slide & squeeze
• If unsuccessful, wait, then try again

Question 23

CL in older children:

Answer 23

• Dislike of wearing spectacles
• Bullied at school/internet social events
- 35% of young (8.5 yr) spec wearers
• Sport/cosmetic appearance are strong motivating factors
• However, a fear of the unknown can also deter potential CL wearers.
- Need to be very patient with children.

Question 24

Older children - hygiene and parent involvement

Answer 24

• Child & parent motivation required
• Child (at least) needs to be hygienic
• Engage the parents in monitoring hygiene & CL care
• Understand CL care & maintenance
• Understand the importance of CL after-care

Question 25

CLI&R - older children

Answer 25

• Can be a struggle sometimes
• Will take time
• Position their head against head rest (prevents backing away)
• Suggest a suitable fixation target
• Have them sit on their hands
• Rather than demand fixation, ‘chase’ the cornea

Question 26

CLI&R - older children: before next visit

Answer 26

• Get parents to instil artificial tears
• Get child to touch conjunctiva with clean finger
• These steps will increase relaxation at this & subsequent visits

Question 27

CL Care

Answer 27

• Same as for adults (CLs are identical in most cases)
• Education of child & guardian(s)
• Degree of involvement with the child
• increase the level of responsibility of the child