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Created on behalf of NHS NES as supplement to workshops on binocular vision and additional techniques. Acuity Testing in Children and how to cope with hysterical vision . Observations. Navigation in clinic / reaching for quiet small toys Holding new toys close for inspection

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Presentation Transcript
observations
Observations
  • Navigation in clinic / reaching for quiet small toys
  • Holding new toys close for inspection
  • Eye contact – often avoided in autistic spectrum
  • Photophobia
observations1
Observations
  • Obvious squint
  • Alternating – VA equal
  • Fixation preference – suspect amblyopia
  • Infantile esotropia – amblyopia rare
  • Intermittent exotropia –amblyopia rare
  • Accommodative esotropia – VA may be good but hypermetropia may prevent habitual clear VA
  • Squint may be secondary to poor unilateral VA e.g cataract or retinoblastoma
    • Infants → esotropia
    • Older children / adults → exotropia
qualitative tests
Qualitative Tests
  • Fixation & following both eyes together
  • Infants prefer their mother’s face
  • Illuminated / moving small toys
  • Do not use noisy toys to assess VA
  • Smooth pursuit should be tested slowly
  • Jerky smooth pursuit does not mean low VA
observations2
Observations
  • Nystagmus
  • VA rarely better than 6/12 – often much worse
  • Amplitude of nystagmus not related to VA
  • Test VA uniocularly AND both eyes open
  • Use +6.0D lens as occluder if significant latent element
  • Near VA much better than distance
    • Test reading acuity at 1/3m and habitual near distance (even if 10cm)
  • Allow to adopt head posture during testing (usually face turn to fixing eye)
observations3
Observations
  • Ptosis
  • Lid ever obscuring pupil?
  • Using chin ↑ head posture
  • Using chin ↑ head posture on upgaze
qualitative tests1
Qualitative Tests
  • Fixation
  • Fixation of deviating eye in manifest squint
  • Fixation should be brisk and accurate
  • Slow / delayed fixation often means low VA
  • Unsteady / no movement to fix indicates eccentric fixation and very low VA
qualitative tests2
Qualitative Tests
  • Fixation preference
  • Spontaneous alternation
  • Alternation after initial occlusion
  • Hold fixation through blink
  • Hold fixation up to blink
  • Hold fixation for few seconds
  • Hold fixation momentarily
  • Immediately return to originally fixing eye
  • Slow to fix
  • Unable to fix

EQUAL VA

DENSE AMBLYOPIA

qualitative tests3
Qualitative Tests
  • Cross fixation if squinting
qualitative tests4
Qualitative Tests
  • Cross fixation if squinting
qualitative tests5
Qualitative Tests
  • Cross fixation if squinting
qualitative tests6
Qualitative Tests
  • Cross fixation if squinting

Tripartite field of fixation

slide13

Right eye fixing looking left 

Left eye fixing looking right 

qualitative tests7
Qualitative Tests
  • Objection to occlusion
  • Look around an occluder / hand
  • Not significant if object to both eyes occluded
  • Different behaviour when occluded
qualitative tests8
Qualitative Tests
  • Daylight / darkroom comparisons
  • Useful in delayed visual maturation / severe disability
qualitative tests9
Qualitative Tests
  • 100’s & 1000’s
qualitative tests10
Qualitative Tests
  • 10 vertical prism
  • Either alternate to look at diplopia or always fix with
  • uncovered eye if VA equal
  • Always fix with same eye if amblyopic
qualitative tests11
Qualitative Tests
  • 10 vertical prism
  • Either alternate to look at diplopia or always fix with
  • uncovered eye if VA equal
  • Always fix with same eye if amblyopic
qualitative tests12
Qualitative Tests
  • 10 vertical prism
  • Either alternate to look at diplopia or always fix with
  • uncovered eye if VA equal
  • Always fix with same eye if amblyopic
qualitative tests13
Qualitative Tests
  • 10 vertical prism
  • Either alternate to look at diplopia or always fix with
  • uncovered eye if VA equal
  • Always fix with same eye if amblyopic
qualitative tests14
Qualitative Tests
  • 10 vertical prism
  • Either alternate to look at diplopia or always fix with
  • uncovered eye if VA equal
  • Always fix with same eye if amblyopic
slide22

Qualitative Tests

  • Optokineticnystagmus
  • Asymmetrical monocular in infants under 4m and infantile esotropia
  • Rotate SLOWLY
  • Lab methods using different frequency gratings overestimate acuity
preferential looking pl tests
Preferential Looking (PL) Tests
  • Keeler /Teller Cards (with/without “puppet screen”)
  • Cardiff Acuity Cards
  • 100s & 1000s / crumbs against light/dark backgrounds
single optotypes
Single Optotypes
  • logMAR single letters
  • Sheridan Gardiner singles (not logMAR)
  • Kay pictures
  • Easier but overestimate VA in amblyopia
  • Make decision-making in young amblyopes difficult
logmar tests
LogMAR Tests
  • More consistent than Snellen notation
  • 6/60 = 1.0

6/6 = 0.0

  • Each line and letter difference standard over chart
  • Letters equally difficult
  • “Crowded”
crowded logmar tests
Crowded LogMAR Tests
  • Bailey-Lovie chart
  • Glasgow Acuity Test (Keeler) - at 3 metres
  • (Cambridge Crowding Cards)
  • LogMAR Kay Pictures - at 3 metres
  • LEA symbols
  • Sonksen test

replacing Snellen & Sheridan Gardiner linear tests at 6 metres

near tests
Near Tests
  • Reduced Snellen
  • Maclure Bar Reading Book
  • Reduced linear Kay pictures
  • Reduced LEA symbols

With most VI children test at 1/3m and wherever they prefer to hold text

refraction
Refraction
  • Cycloplegic refraction
  • Undilated retinoscopy – gross refractive error
    • media opacities
    • Bruckner reflex
    • Anisometropia
    • Gross astigmatism
  • “Mohindra” retinoscopy in dark
crowding separation difficulties
Crowding / Separation Difficulties
  • Present at threshold in everyone
  • Characteristics
    • Ends of rows clearer
    • Letters correct but jumbled up
  • Exaggerated ++ in amblyopia
  • ?Worse if initial VA very low
  • Occlusion may improve singles acuity, but less for linear
  • VA may regress at end of occlusion
  • Record more details of VA e.g. 6/12, but crowding from 6/36
electro diagnostic tests
Electro-diagnostic tests
  • VEP, ERG,
  • Indicated when VA appears to be, or is suspected of being, reduced despite normal appearance on conventional examination e.g. Inherited retinal conditions
  • VEP acuity overestimates recognition acuity
  • Generally used in diagnosis
  • Occasionally used to monitor progress in children with congenital cataracts
practical tips
Practical Tips
  • If occlusion likely to be difficult, do all both eyes open tests first
  • On first visit test likely better eye first
  • On subsequent visits test amblyopic eye first before co-operation lost
  • When moving on to more difficult test, try to do “old,” easier one, on same visit – especially if being occluded
functional hysterical loss of vision
Functional /”Hysterical” loss of vision
  • Children with genuine low VA are cautious in new situation of clinic, while these children enter normally
  • Relatively untroubled by apparently severe symptoms
  • Running their lives normally most of time
functional hysterical loss of vision1
Functional /”Hysterical” loss of vision
  • Read VA chart very slowly from the top, not just from near threshold
  • Tricks
    • Cancelling + / - lenses – put up plus first
    • Testing VA at different distances
    • Use Bagolini glasses
    • If claiming unilateral loss use prisms to give diplopia
  • Watch pupil reactions for near – may dilate for text
  • Dynamic retinoscopy
  • Compare “tested” vs natural accommodation
  • Need good VA to get good stereoacuity – say TNO is a colour test
  • Check fundi and media carefully & refer for ophthalmologist opinion or scans if cannot improve VA
functional hysterical loss of vision2
Functional /”Hysterical” loss of vision
  • Do not accuse of malingering / lying
  • Take it seriously
  • It “happens” to children and is common
  • Reassure child that their eyes are normal and it will get better with time
  • Speak to parents alone
  • Reassure, but ask parents to think about whether any cause they can think of
    • Bullying, dyslexia, anxiety, abuse
    • Offer a range of severity of causes
  • Be mindful of formal reporting procedures for child abuse