University of Edinburgh
 

Understanding the diagnosis: Childhood visually impairing conditions

Presented on Thursday 1 November 2007

Ocular Conditions

Dr Andrew Blaikie, Consultant Ophthalmologist, Fife

Purpose of 'Lecture'

  • Discuss the most common conditions that you see in your job
  • Opportunity to ask questions and pick our brains
  • Lots to talk about – can't cover everything

NOT the Purpose of 'Lecture'

  • Tell you how to manage child from an educational point of view
  • Suggest low vision management
  • I'm not knowledgeable in that field
  • Hopefully I can learn from you

References

  • VIS or SSC website
  • Dutton & Bowman book
  • Taylor and Hoyt book

Anatomical Sites

  • Whole Globe
  • Cornea
  • Lens
  • Uvea (Iris, Ciliary Body and Choroid)
  • Retina
  • Optic Nerve
  • Brain

Whole Globe

graphic of eye

anatomical site

Whole Globe

whole globe

Albinism

albinism

pigmentation

Albinism

  • Poor acuity
  • Photophobia
  • Nystagmus
  • Dark glasses
  • Hat
  • Sunscreen

Genetics

  • Chromosomes
  • Autosomes
  • Sex
  • Inheritance patterns
    Dominant
    Recessive
    X-linked

46 pairs of chromosomes

  • 22 pairs of autosomes
    (numbered by size)
  • 1 pair of 'sex' chromosomes
    (X or Y named by shape)

Dominant

  • Only requires one copy of a misprinted gene for the condition to be expressed
  • Males and females equally affected
  • 1 in 2 children of affected parent will also be affected
  • 1 in 2 will be normal and not carriers
  • Don't really get carriers (but you can if disease is only weakly expressed)

Recessive Inheritance

  • A 'recessive' condition to be 'manifest' requires both copies of the gene to be misprinted
  • Affects male and females equally
  • If only one copy misprinted then they are a 'carrier'
  • If both parents carriers then 1 in 4 chance child will be affected
  • 1 in 2 chance child will be carrier
  • 1 in 4 chance neither affected or a carrier

X-Linked

  • Males XY Females XX
  • Most x-linked conditions 'recessive' so mainly boys affected
  • Affected male will always pass on misprinted gene on X to daughters
  • None of his sons will get his X and so none will be affected or carriers

Genetics

  • Confused?
  • Draw out the diagrams and stare at them and it makes sense

Nystagmus

  • Congenital
  • Acquired (usually adults)
  • Sensory (eye problem)
  • Motor Congenital (brain problem)

Nystagmus Symptoms

  • Acquired: Oscillopsia and Reduced VA
  • Congenital: only reduced VA
  • Null point
  • Abnormal Head Posture (AHP)

Nystagmus: Treatment

  • Glasses
  • Prisms
  • Contact lenses
  • AHP Surgery

Coloboma & Microphthalmia

Coloboma

  • Part of eye missing
  • Infero-nasal part
  • Closure of embryological cleft
  • Iris, retina, optic nerve

coloboma

eye scan of coloboma

graphic

Microphthalmia

microphthalmia

Issues

  • How much vision
  • Anything else wrong
  • Retinal Detachment
  • Orbit growth and facial symmetry
  • Environmental cause?
  • Genetic Counselling

Glaucoma

  • Increasingly uncommon cause of childhood VI
  • Early diagnosis
  • Preventative treatment

glaucoma

glaucome

glaucoma

graph of anatomical site

Cornea

Peter’s Anomaly

peter's

Lens

Cataract

cataract

Uvea

Aniridia

aniridia

Uveitis

  • 'Itis' means inflammation
  • Uvea is coloured part of eye

Anterior : Iris
Intermediate: Ciliary Body
Posterior: Choroid

diagram of iris

uveitis

Retina

graph of retina conditions

Retina

  • Central Part of Retina: Macula
  • Fine detail
  • Colour
  • Daylight

retina

Photoreceptors: Rods

  • No colour (because only one type)
  • Poor acuity
  • Work well in dark
  • Movement

Photoreceptors: Cones

  • Colour (because 3 different types)
  • Fine detail
  • Daylight
  • Still

Macular Dystrophies

macular dystophy

macular dystrophy

Stargardt’s Disease

stargadt's

stargadt's

Retinitis Pigmentosa

  • Description of appearance
  • Disease of any part of the retina
  • 'Progressive' rod and cone dystrophy
  • Inherited
  • Isolated ocular condition
  • Associated with other conditions
  • A syndrome
  • Inherited condition

Symptoms

  • Poor night vision: 'Night Blindness'
  • Loss of peripheral visual field: 'Ring Scotoma'
  • Gradual loss of visual acuity
  • Catarcat
  • Macular Oedema

RP – mottled appearance

mottled appearance

retinitis P

Leber's Congenital Amaurosis

  • Non-Progressive Rod Cone Dystrophy
  • Inherited
  • Different types
  • All photoreceptors badly broken
  • Poor vision: often NPL

Any treatment?

nature magazine

journal paper

transplanted cells

transplanted cells

transplanted cells

journal paper

Retinopathy of Prematurity

  • Blood system immature
  • Parts of retina have no blood supply
  • 'Ischaemic': leads to release of growth hormones (VEGF)
  • Causes Damage: Retinal Detachment

rop

rop

Retinopathy of Prematurity

  • Screening programme
    <32 weeks
    <1500 g
  • If ROP reaches a bad stage then treat

Treatment

  • Laser or cold 'cryo' therapy
  • Kills peripheral retina
  • Switches off VEGF release
  • Reduces risk of detachment by 90%

laser treatment

Survivors with no ROP may still have VI: Later problems

  • Myopia
  • Squint
  • Amblyopia
  • CVI (25% of premature babies have PVL)