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