The Paediatric Eye examination

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The Paediatric Eye examination

• Dr Julie-Anne Little PhD MCOptom
• Lecturer, University of Ulster, U.K.

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• This presentation summarises the eye examination
  of a child.
• There are several different considerations to
  that of an adult examination.
• In the UK the NHS enables optometrists to provide
  an eye examination to a child at no cost.

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Paediatric eye testing

• While early testing for young children is widely
  advocated, a recent UK paper indicates some
  optometrists do not offer eye examinations to
  children under the age of 3 years.
• Why?
• Lack of confidence in this area?
• Lack of appropriate equipment?

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Paediatric eye testing

• There are challenges to testing young children
• It requires, skill, speed and enthusiasm.
• Also requires some variety of visual acuity
  tests, and binocular function tests
• All these are inexpensive types of equipment

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Visual Development

• Infancy and early childhood is an important time
  in visual development.
• The eyes grow and emmetropise
• Vision improves
• Stereopsis matures
• Accommodation develops
• Etc

Hubel
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Visual problems

• Visual disorders are the leading cause of
  childhood disability.
• Aside from congenital pathology common disorders
  include amblyopia, strabismus and refractive
  errors.
• Early detection means prevention and better
  treatment.
• For example, amblyopia is the most common cause
  of monocular visual loss in young people in the
  western world. It has been found to have
  repercussions on general educational development
  and reading skills

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Amblyopia

• It is defined as a reduction in vision in one or
  both eyes which has no organic pathology.
• It is a cortical phenomenon, caused by unequal
  competitive inputs from the two eyes into the
  primary visual cortex.
• Classically considered as a difference in vision
  of 2 lines on an acuity chart.
• Treated by refractive correction, and perhaps
  occlusion of the good eye

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Amblyopia

• Main types are
• Anisometropic a refractive difference between 2
  eyes, approximately 1.00D or more
• Strabismic A strabismus causing amblyopia in
  that strabismic eye
• Deprivation e.g. a cataract causing an
  obstruction to developing vision
• Amblyopia can be binocular as well as uniocular

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Strabismus

• Strabismus could be described as a deviation of
  an eye such that both eyes do not have parallel
  lines of sight.
• General incidence of strabismus in the population
  is approximately 4.
• The likelihood of strabismus increases
  dramatically with family history.

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Refractive Errors

• Refractive errors are not common in early
  childhood the majority of children will
  emmetropise.
• This is shown in the following graph where a
  level of hypermetropia (average 2.50DS) is found
  in infancy, and this changes to a normal
  distribution with the majority (80) of children
  demonstrating emmetropia.
• This usually occurs by 1 year of age.

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Refractive Error

• Green line cycloplegic refraction on infants
  (0-6mths)
• Blue line non-cycloplegic refraction on infants
  (0-6mths)
• Red line Refraction in older children

Adapted from Gwiazda et al 1993
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Prematurity

• Prematurity increases the risk of visual
  conditions, and any infant with neurological or
  developmental disorder has approx a 40 chance of
  developing a visual problem (Mackie 1995).
• Also note that a premature infant is more likely
  to have myopia and astigmatism.

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Paediatric eye examination

• Now, I want to take you through the different
  considerations and important aspects of testing
  young children.
• For any parent, a first eye examination generally
  arises because
• - they have concerns regarding the childs eyes
  or vision,
• - there is a family history of an eye condition,
• - or they have been informed that there child may
  have an eye problem , for example, by a health
  care professional

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History Symptoms

• So, it is very important to get a thorough
  history from the parent
• Reason for visit any concerns?
• Family history of amblyopia, strabismus, high
  refractive errors?
• Birth history full term, normal delivery?
• Visual behaviour of the child clumsy?, visually
  inattentive? Close viewing distance?

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Preliminary tests

• Begin with a general observation of the child
• Hirschberg test gross check of eye alignment
• Pupil reactions round and equal
• Ocular motility

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Tests of binocular function

• Cover test near usually easier to obtain!
• Use a detailed target.
• Stereopsis
• Choose an age-appropriate test, e.g. Lang, Titmus
  fly, Frisby
• 20 dioptre base out prism test for motor fusion
• Good for infants and young children to check
  motor fusion

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Vision

• Very important to get a measure of vision.
• Monocular if possible sticky occluders and
  occluding glasses useful.
• Child should do the most sophisticated test of
  visual acuity they can perform.

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• In visual development, visual acuity improves
  rapidly during the first year of life and then
  matures more gradually to adult levels at
  approximately 5-6 years of age.

Adapted from Mayer et al 1995
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Preferential looking tests of vision

• Keeler/Teller cards for infants
• Cardiff acuity cards for
• toddlers

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Picture tests of vision

• Kay pictures
• Lea symbols
• Both LogMAR scoring

• Naming or matching can be done by the child.

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Letter tests of vision

• Letters LogMAR acuity cards
• Snellen type chart

Again, child can match or name letters
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Effects of Crowding

• Crowding phenomenon process where single letter
  acuity better than that measured by crowded
  letters.
• Crowding more sensitive measure
• Amblyopia more susceptible to crowding effects

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Vision

• To correctly interpret a childs visual results
  one needs to know the normal range of vision for
  that age.
• If a difference in acuity is found between eyes,
  one should relate this to other findings, i.e.
  refractive error, binocular function, stereopsis,
  ophthalmoscopy etc

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Normal levels of vision

• Preferential looking tests (Mayer et al 1995)
• 1 cpd at newborn
• 6-13 cpd at 1 yr
• Cardiff acuity test (Monocular Adoh Woodhouse
  1994)
• 12-18 months 0.4 to 0.8 LogMAR
• 18- 24 months 0.1 to 0.7 LogMAR
• 24-30 months 0.1 to 0.5 LogMAR
• 30-36 months 0.0 to 0.3 LogMAR

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Normal levels of vision

• Kay pictures (singles) (Binocular Deves et al
  1996)
• 24 mths 0.24 to - 0.28
• 3 years 0.14 to - 0.28
• LogMAR letter acuity (Monocular Sonksen et al
  2007)
• 3yrs 0.450 to - 0.025 LogMAR
• 4yrs 0.250 to - 0.100 LogMAR
• 5 yrs 0.175 to - 0.150 LogMAR
• 6 yrs 0.175 to - 0.200 LogMAR
• 7 yrs 0.175 to - 0.225 LogMAR

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Repeatability of visual measure

• What is a significant difference between eyes or
  between visits?
• It depends on how youve tested vision...

• Keeler cards 2 cards
• Cardiff acuity test 2 cards
• Kay pictures 2 lines
• Snellen acuity 3 lines
• LogMAR acuity test 4 letters
• (Saunders et al 2002)

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Co-operation

• It is often useful to note the level of
  co-operation of the child. This helps in
  comparing results found in future tests.
• Note whether the child is tiring or not.
• Often you get good co-operation for one eye and
  then the child gets bored.
• You may not get everything at the one visit, so
  getting the child back to test the other eye is
  feasible.

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Measurement of Refractive error

• There are several ways of assessing refractive
  error
• Cycloplegic retinoscopy
• Mohindra retinoscopy
• Distance static retinoscopy

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Cycloplegic refraction

• Often referred to as the gold standard method
• Paralyses accommodation allows full
  hypermetropia to be measured
• Some may argue all children should have a
  cycloplegic refraction.
• Definitely indicated where unexplained reduction
  in VA (in one or both eyes), strabismus or large
  phoria, poor stereopsis, first examination.
• Workshop on cycloplegic later today

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Mohindra retinoscopy

• Also a useful method. Utilises fact that in a
  totally dark room your (dim) retinoscope light is
  not an accommodative target.
• Work distance is 50cm. However, subtract -1.25DS
  from the result.
• However, children often dont like the dark!
• Again, workshop on this later

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Distance static retinoscopy

• Useful in older children.
• Relies on the childs co-operation to fixate on a
  distant target.
• Can be used in subsequent visits if child has a
  stable prescription.

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What is a significant refractive error?

• It depends on
• Age
• Binocular status
• Visions
• Anisometropia found

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Hypermetropia prescribing guidelines

• Infants are born hypermetropic.
• Correction in the first year could interfere with
  emmetropisation.
• Only correct refractive error in infancy if
  hypermetropia is high.
• Uncommon for hypermetropia to persist after 2
  years.
• Amount of correction depends on other factors,
  i.e. presence of strabismus, amblyopia etc.

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Astigmatism prescribing guidelines

• It is common to find amounts of astigmatism in
  infancy.
• This tends to resolve by the age of 1-2 years.
• Large amounts of astigmatism (gt2.50DC) over the
  age of 1 year should be corrected
• Persistent astigmatism (gt 1.50DC) at 2 years and
  older should be corrected.

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Anisometropia prescribing guidelines

• Anisometropia is a difference in prescription
  between the two eyes.
• It is usually defined as difference of
• /- 1.00D or more.
• Consider with other findings - If anisometropia
  is found in conjunction with amblyopia and/or
  strabismus, correction of refractive error will
  likely help treat this.
• If not prescribing full correction, one needs to
  keep the anisometropic difference constant

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Myopia prescribing guidelines

• Myopia is uncommon in infancy.
• Small amounts of myopia tend to be left
  uncorrected initially as a childs world is near.
• As a child get older, some develop myopia. A lot
  of research into why myopia prevalence is
  increasing.
• Ethnicity plays an important role.

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Strabismus

• In the UK, if a strabismus is found, the
  community optometrist can begin the process of
  correcting any significant refractive error.
• The child is then usually referred for
  ophthalmological/orthoptic treatment in a
  hospital setting.
• Treatment may include correction of refractive
  error, patching and/or surgical correction

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Fundus examination

• Important to examine the fundus
• to ensure no pathology.
• Abnormal findings could explain poorer than
  expected vision.
• Direct ophthalmoscopy can be difficult with young
  children due to the proximity required. They also
  have a tendency to keep looking at the
  ophthalmoscope light.
• Indirect methods can be more successful!

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Dispensing

• Commonly spectacles are dispensed, however
  contact lenses may also be indicated if the level
  of anisometropia is high, or the refractive error
  is very high.
• Important to provide appropriate fit of
  spectacles often the most troublesome part!
• Need to consider the thickness and weight of
  lenses.

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Conclusions

• Paediatric testing a really worthwhile aspect of
  optometry.
• Chance to aid development of a child.
• Challenging and worthwhile aspect of optometry.
  Need skill, confidence and speed.
• Dont forget you may not get all done in one
  visit.
• Potential to really benefit your patient.
• Grateful parents if a problem is detected and
  dealt with.