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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
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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 • Visibility sweets, fixation patterns, Catford drum • Resolution preferential looking, acuity card procedure, Cardiff cards • Recognition Snellen, logMAR • Sensitivity to detect vision impairment amblyopia
Vision Assessment - Infancy • Birth • Fix & follow • 6 weeks • Smile • 4 months • Reach • Anytime • Grating response • History
& why parents are such good historians Babies have an innate preference to look at patterns, such as a face This is the basis of vision testing in infancy
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 • Prevalence developed countries 0.3/1000 developing 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 • Preventable infections - trauma - cataract - ROP anterior segment • Partially preventable DR - glaucoma - ROP - ARMD - cataract anterior & posterior segment • Non-preventable malformations - 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 • Prenatal • Malformations, infections & toxaemia • Perinatal • Hypoxic-ischaemic encephalopathy & PVL • Haemorrhage • Hypoglycaemia • Encephalitis • Acquired later • Cardiac arrest, trauma, neurodegeneration
CRYO-ROP study: intervention @ “threshold” (5 continuous or 8 cumulative clock hours of stage 3+) 1988 Cryotherapy or laser Treatment “destroys evidence” Problems with Screening & Treatment
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 • Maskedeffect of attending an ophthalmic unit