The Ophthalmology of
Childhood Vision Impairment
Alistair Fielder
City University, London
This version probably has little stand-alone value but is meant as an
accompaniement to the lecture
Topics
• Role of clinician
• Assessment of visual functions
• Causes and epidemiology of VI
• VI issues specific to children
• Patterns of presentation & development
• Impact of VI
• Clinical role
“Ophthalmologists tell me what I can see,
but it has nothing to do with what I can do”
Role of Clinician in VIOrthopist, Optometrist & Ophthalmologist
• Diagnosis & quantification• Treatment• Involve & link other agencies• Communication
– Client & family, others
• Registration• Monitor• Research• Maintain contact - be amenable
Through the ages
What does he see?
How do I measure?
Approximation or precision?
& when can I do this?
How long for parents to wait?
Paediatric OphthalmologyVision tests
• Visibilitysweets, fixation patterns, Catford drum
• Resolutionpreferential looking, acuity card procedure, Cardiff cards
• RecognitionSnellen, logMAR
• Sensitivity to detect vision impairment
amblyopia
Vision Assessment - Infancy
• Birth– Fix & follow
• 6 weeks– Smile
• 4 months– Reach
• Anytime– Grating response– History
Babies have an innate preference to look at patterns, such as a face
This is the basis of visiontesting in infancy
& why parents are such good historians
What Visual Functions?Their development
• Visual acuity
• Contrast sensitivity
• Colour
• Binocular vision
• Visual field
• Movement
Causes of VI in Working Years
• Diabetes mellitus• Retinitis pigmentosa• Glaucoma• Trauma• Macular degeneration
Survival
Childhood Visual Impairment
• Prenatal 60%genetic 50%
intrauterine 10%
• Perinatal 23%ROP 5-10%
asphyxia 13%
• Childhood 13%male preponderance
• Prevalencedeveloped countries 0.3/1000developing countries 0.6 to 1.1/1000
• Additional disability in 40-70%Preterm birth
Impact of Low Birth Weight on the Visual Pathway
• Severe visual impairment (VI)– all births - 1.25/1000– <1500 g BW - 25.9/1000 births
• 1% of all live births, BUT 17.5% childhood VI• X 26 for babies 2500-3499 g BW
• Associated impairments with VI– <1500 g BW 72%– >3500 g BW 44%
Categories of VI
• Preventableinfections - trauma - cataract - ROP
anterior segment
• Partially preventableDR - glaucoma - ROP - ARMD - cataract
anterior & posterior segment
• Non-preventablemalformations - genetic - ROP - ARMD glaucoma - cataract
anterior & posterior segment
Child Who Cannot See Classification
• Obvious ocular abnormality– Anterior & posterior segment
• Cataract• Optic atrophy• ROP +
• No obvious ocular abnormality– Mainly posterior segment or cerebral
• Optic nerve abnormalities– Atrophy - hypoplasia
• Delayed visual maturation• Cortical vision impairment• Retinal anomalies
– Retinoschisis, achromatopsia– Lebers amaurosis– Albinism
• Nystagmus
Delayed Visual Maturation
• Type 1 - isolated abnormality– A Normal perinatal period– B Perinatal problems
• Type 2 - obvious & permanant neurodevelopmental delay
• Type 3 - nystagmus(albinism)
• Type 4 - severe developmental, structural ocular abnormalities
(not albinism)
Cerebral Vision Impairment
• Reduced vision• Normal eye examination & pupil
responses• Absence of nystagmus• Natural history
– <75% show some improvement– Early improvement more likely to be
complete
CVI – Aetiology
Stage 3: Severe ROP
Problems with Screening & Treatment
• CRYO-ROP study: intervention @ “threshold” (5 continuous or 8 cumulative clock hours of stage 3+)
• 1988
• Cryotherapy or laser
• Treatment “destroys evidence”
ROP- End Stage
Evaluation I
• History• Overview assessment• Full ophthalmic examination including
– Vision assessment– Ophthalmic examination
• Paediatric assessment• Investigations
– Ophthalmic– Paediatric
Children need referring
Evaluation II
• Ophthalmic tests– Electrophysiology
• VEP• ERG• EOG
– Ultrasound– EUA
• Other tests - biochemical, etc• Neuroimaging• Referral(s)
Electrophysiological test&
Neuroimaging
Nystagmus
Is the pattern of nystagmus informative?• Vision• Localisation
– Anterior – Posterior
• Aetiology– Ocular– Neurological
Patterns of Presentation
• Sudden & dramatic
• Insidious
• Masked
effect of attending an ophthalmic unit
Predictive Value of Vision Tests
Patterns of visual development
Patterns of Visual Development
Patterns of Visual Development
Vision deficit resulting from any obstacle to visual development
SquintBlurred vision Refractive
Opacity
Especially of 1 eye
Impact of VI on the Child
• Visual functions• Cognitive
– Perception of objects in their totality & in environment– Spatial and intermodal interaction impaired
• Motor development - complex• Language• Social play, social interaction• Poor self-concept & low self-esteem• Other behaviours - eg sleep
Education, leisure, social, health
Sleeping patterns of visually impaired
Impact of VI on the Family
• Diagnosis generated– Phases of grief, anger, loss & fear
• More care required for daily living tasks
• Lack of responsiveness by child– Loneliness, anxiety, depression in parents
• Behavioural problems in siblings
• Marital stress
“Ophthalmologists tell me what I can see,
but it has nothing to do with what I can do”
VI - Impact on Child & Family
The 5 senses interact & are interdependent, so VI has widespread &
cumulative impact on development
In most instances -
VI is not stable during childhood,
thus its impact on life’s activities varies
Impact of VI on the Child
• Visual functions• Cognitive
– Perception of objects in their totality & in environment– Spatial and intermodal interaction impaired
• Motor development - complex• Language• Social play, social interaction• Poor self-concept & low self-esteem• Other behaviours - eg sleep
Disability & Divergence from Full Function
Impact of VI on the Family
• Diagnosis generated– Phases of grief, anger, loss & fear
• More care required for daily living tasks
• Lack of responsiveness by child– Loneliness, anxiety, depression in parents
• Behavioural problems in siblings
• Marital stress
Functional Effects of VI
• VI severity – Total - severe - mild
• What do these categories mean for each activity of life?– Education, leisure, social, health
What is Functional Vision ?
• Acuitydistance & nearspeed of reading & information processing
• Contrast• Colour• Field of vision• Illumination• Movement
What do we measure?
Role of Clinician in VI
• Diagnosis & quantification• Treatment?• Involve & link other agencies• Communication
– Client & family, others
• Registration• Monitor• Research• Maintain contact - be amenable
Through the ages
VI Support
• Medicalphysicianophthalmic
• Opticalspectacles
LVAs
• Rehabilitation• Social services• Education• Registration
Disability Through the Ages
• Diagnosis• Infancy• Preschool• School age• After school• Adult life
Much VI is not stable
Info forgotten, misheard, wrong, updatable
Communication
• Between & within– Services - statutory and voluntary– Locations - community & hospital, etc– Professions
• When?– Depends on individual’s & family requirements
• Education, occupation, social, leisure, health, etc
• For whom?– Client & professional
Treatment
the eye
Treatment
the child & family
Components of Disability Care
• Specialist expertise• Always available & amenable• Affordable• Communication• Link - education, health, social services • Involve the client - parents• Key worker