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Paediatrics YR > Optometric examination of children part 2 > Flashcards

Optometric examination of children part 2 Flashcards

1
Q

what does an accurate refraction help with in a child

A

establish if child’s visual system is developing normally, which is the first thing you want to ask yourself

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2
Q

what does correcting ametropia allow for in a child and what may it explain

A
  • Allows child to achieve maximum possible VA
  • May explain lack/reduction in BSV
    i. e. give clues about whether their refractive error is normal or not
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3
Q

what are auto refractor readings found to be in children under:
non-cycloplegic conditions
and
cycloplegic conditions

A
  • Under non-cycloplegic conditions, tends to overestimate myopia
  • shown to be accurate under cycloplegia

so use with caution, some clinicians use it to aid their RET results

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4
Q

what is found to be more accurate than an auto refractor

A

retinoscopy by experienced clinician

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5
Q

what are the 3 different available methods for ascertaining refractive error using retinoscopy

A
  • Static (or dry)
  • Mohindra technique
  • Cycloplegic refraction
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6
Q

what is dynamic retinoscopy used to assess in children

A

their accommodative state

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7
Q

what is meant by static or dry retinoscopy
which target needs to be used
how should it be done
which 2 ways can it be done and what can be a drawback to one of these ways

A

= Static = static accommodation i.e. relaxed

  • Use distance fixation target e.g. clown
  • Children’s trial frame
  • Hold lenses in front of both eyes
    Neutralise each meridian separately
  • 50cm working distance may be more appropriate
    Make adjustment for working distance
  • Remember to fog contralateral eye
  • Needs to be quick (due to short attention span)
  • Can be done awake or asleep
  • Bell’s phenomenon may be a problem if asleep as eyes can roll up if sleeping
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8
Q

what is the working distance for static/dry retinoscopy

A

50cm = -2.00D

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9
Q

list 3 things that have been found about refractive error with static/dry retinoscopy on a pre school/young child

A
  • Tends to result in spherical error more negative i.e. less positive (by up to 4DS)
    This can occur into teenage years
  • Little difference between measurements of astigmatism
  • Non-cycloplegic static retinoscopy far less reliable in paediatric subjects
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10
Q

when will it be desirable to do a cycloplegic refraction and give 8 reasons when it is essential to do

A

desirable:
in all new cases, for a baseline measurement

essential:
- reduced stereopsis
- reduced V/VA to get the true refractive error
- suspect or manifest strabismus
- large decompensating esophoria (will tell us if theres any latent hyperphoria or hyperopic element)
- FH strabismus or high hypermetropia
- suspect pseudomyopia
- anisometropia > 1D
- poor accommodation

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11
Q

what is pseudo myopia

A

when the visual state is pretending its myopic, as if its gone into an accommodative spasm, so they’re not really myopic, they just need to relax their accommodation

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12
Q

list 3 advantages of a cycloplegic refraction

A
  • Reveals latent hyperopia
  • More accurate refraction
  • Aids fundus check (as it dilates the pupil)
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13
Q

list 4 disadvantages of a cycloplegic refraction

A
  • Photophobia
  • Distress (sting from drops)
  • Temporary near vision problem
  • Risk of adverse reaction
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14
Q

list 4 adverse reactions to cycloplegia
which 2 affects it has
which group of children have increased sensitivity to cycloplegics

A

“blind as a bat” = vision blurry
“dry as a bone” = thirsty
“red as a beetroot” = flushed cheeks
“mad as a hatter” = sleepy

CNS effects
Local effects

children with Down’s syndrome increased sensitivity to cycloplegics

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15
Q

when will you give Cyclopentolate HCL 1%
when will you give Cyclopentolate HCL 0.5%

what allowance is not made
when does maximal cycloplegia occur
how much residual accommodation is left
what does it not always produce

A

Cyclopentolate HCL 1%:
> 6 months

Cyclopentolate HCL 0.5%:
12 years (if think pseudo myopic)
if light irides

  • No tonus allowance made (don’t tweak rx after drops)
  • Maximal cycloplegia 10 – 55 minutes
  • Residual accommodation 1.00 - 2.50D
  • Does not always produce adequate cycloplegia
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16
Q

what should you do before starting your ret and after instilling cyclopentolate drops

A

check for any residual accommodation

write down the time of putting the drops in

17
Q

which 2 ways is advised to instil the cyclopentolate drops

what do some practitioners use with it and why

A
  • Drop onto lashes of closed eye
  • Use atomiser (spray used in hospitals) (availability limited)

Some use Proxymetacaine HCL 0.5% first

  • Prevents stinging but child may object to cyclo drop
  • Increases absorption
18
Q

when will you use 1% Cyclopentolate AND 1% Tropicamide
why will you choose to use this combination over atropine
what is the residual accommodation with this

A
  • Cycloplegic refraction in African children i.e. very dark iris
  • Less toxic than Atropine
  • Residual accommodation 0.63DS
19
Q

why will you not decide to use 1% atropine
which types of clinicians are more likely to use it
how much residual accommodation is there
what is the tonus allowance

A
  • Severe side-effects; risk of poisoning
  • Additional Supply or Patient Group Direction
  • Residual accommodation 0.04D

Tonus allowance:

  • 1.00DS for low myopes/hyperopes
    0. 00DS for moderate/high myopes
20
Q

what is the mohindra retinoscopy technique also called
how is it done
what is the fixation target
what is the working distance
what will you do differently with the working distance and why

A
  • Also called near (monocular) retinoscopy
  • On one eye at a time (occlude one eye)
  • Carried out in a totally dark room
  • Light of ret used as fixation target
    Assumes eye is in normal resting state
  • 50cm working distance (= 2DS)
  • Mohindra: subtract 1.25DS from findings
  • allowing for 0.75DS accommodation that went on because of light stimulus
21
Q

list 3 rules of thumb when carrying out subjective refractive error on children

A
  • Don’t attempt if child
22
Q

when will you measure accommodation on a child
which children will you do it on
how will you do it if doing subjectively
what can be difficult with this

A
  • Do before instilling cycloplegic drops
  • In older children
  • Check N5 acuity at 5cm
  • Use budgie stick
  • Or RAF rule
  • Push-up method
  • Requires subjective response – unreliable
  • Difficulty interpreting blur point
23
Q

which type of subjective accommodation test will you use on a child
what is it used to assess
what is it useful in
what is it NOT used for
when and how will you do it
what are the normal findings
what does abnormal findings indicate and how may you want to manage them

A
  • Dynamic retinoscopy
  • Used to assess accommodative state
  • Useful if suspected accommodative insufficiency
  • NOT used to assess refractive state
  • After ret
  • With distance Rx
  • Check for symmetry
  • Only need to check along single meridian
  • Child fixates accommodative target in plane of retinoscope (ask what pics they can see)
  • Room lights so child can see targets!
  • In theory, neutral should be found at child’s working distance
  • In reality, small with movement observed
  • +0.25 to +1.00DS lag is normal
  • if more then px has insufficient accommodation
  • may want to prescribe bifocals or try to manage with the refractive error we have found
24
Q

how is the Nott and the MEM method of dynamic retinoscopy carried out

A 
- Nott method
Patient fixes a target in plane of retinoscope
Distance correction in place
With movement noted
Move ret forward until reversal noted
Dioptric distance equals accommodation
  • MEM method (Monocular Estimation Method)
    Movement neutralised with positive lenses
25
Q

why is it important to carry out a visual field assessment in children
how should it be done

A
  • Visual field loss very advanced in children before behaviour changes
  • Confrontation
  • Occlude one eye
  • Bring toy around head
  • Note point at which child looks at toy
26
Q

list 4 things that can be used to assess the ocular health of the external eye
how should it be done

A
  • Pentorch and loupe
  • Ophthalmoscope
  • Burton lamp
  • Slit-lamp
  • Child on parents knee
  • Be quick
  • Encourage
27
Q

which 2 ways can you assess the ocular health by ophthalmoscopy on a child

A

Direct ophthalmoscopy

Indirect ophthalmoscopy

28
Q

what should you do when performing direct ophthalmoscopy on a child
what is easy to view
what is not easy to view and why
what can you do to avoid this problem

A
  • Dilated pupils
  • Macula easy to view
  • Disc hard to find
  • Because child will look at your ophthalmoscope light
  • Play a game with the child that requires them to look at different positions of gaze
29
Q

which 2 ways can you do indirect ophthalmoscopy on a child
what advantage does indirect have
what may the child object to

A
  • Hand held or head set
  • Advantage = binocular view and large FOV so can assess the fundus a lot quicker
  • Objection to light levels
30
Q

when should a child know their primary colours

what may young children not know

A
  • by age 3-4 years

- Young children may not know their numbers

31
Q

list 3 things an ishihara test will have to aid for unlettered persons
and which age children it is suitable for and why not any younger

A
  • Simple pathways
    Lack fine motor control
  • Matching or naming
  • Shapes, circles and squares
  • Suitable age 3 – 6 years
  • Younger children don’t have fine motor skills to trace
  • so can just test when they’re a bit older
32
Q

what affect will a colour defective father and a mother who has normal colour vision have on their sons and daughters

A
  • sons = will not be colour defective

- daughters = all will be carriers

33
Q

what affect will a mother who is a carrier (of the colour defective gene) have on her sons and daughters

A
  • sons = 50% will be colour defective

- daughters = 50% chance of being a carrier

34
Q

what is the prevalence of colour deficiency in males and females
how do boys usually inherit their colour deficiency
how are colour vision defects usually in children

A
  • Prevalence of 8% males and 0.5% females are colour defective
  • Boys usually inherit via a maternal grandfather, not from their father
  • Colour vision defects are usually congenital in children

Paediatrics YR (5 decks)

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