Paediatric Ophthalmology

Question 1

Visual development

Answer 1

• Vision develops as they eyes and brain mature.
• Premature eyes:
  
  • Eyelid closure
  • Abnormal iris function
  • Aqueous drainage
  • Delayed retinal maturity
• Starts at birth and slows down around the age of 7 although vision continues to develop throught the second decade.
• Birth:
  
  • 6/60-6/90
  • Spherical lens
  • Immature macula
  • Until 3 months only black and white, angles
• 3 months:
  
  • Coordination of head and eye movements
  • Can see targets (2.5cm)
  • Ventral and dorsal streams coordinate (attention and searching)
• 5-6 months:
  
  • Able to examine
  • Coordination smoother
  • 1m-3ft
• 6-9 months:
  
  • Mature levels of acuity
• 9-12 months:
  
  • Familiar and unfamiliar
• 24 months:
  
  • Myelination of optic nerve complete
• 3 years:
  
  • Structurally complete (trebled in size)
  • Drawing crude circles
  • Matching objects (peg and hole)
• 5-7 years:
  
  • Myelination of prefrontal cortex spurt in density
• Puberty
  
  • Pruning
• Any process that delays the growth or development of a child can delay visual development.

Question 2

Visual assessment in a child

Answer 2

• Early life - fixing and following, eye popping, red reflex
• Baby to toddler - preferential looking, red reflex
• 10 weeks - gratings
• Toddler - eye occlusion, red reflex
• 2 years - identifying or matching pictures
• 3 years - letter chart

Question 3

Amblyopia

Answer 3

• Poor vision with a structurally normal eye
• In first 7 years if image recieved by brain from one eye is poorer then the brain will favour the other and amblyopia will develop (one eye will turn off) - reversible if treated.
• Causes include:
  
  • Reduced view through eye (i.e. ptosis, cataract)
  • Unequal focus (i.e. one eye is more long or short sighted = anisometropia)
  • Misalignment of eyes (i.e. squint)
• An occluding patch or atropine eye drops are used to treat amblyopia and improve vision. The better eye is occluded, forcing the poorer eye to be used to see. The patch is always worn under glasses if prescribed.

Question 4

Squints

Answer 4

• Eye/s turned inwards - esotropia or convergent squint
• Eye/s turned outwards - exotropia or divergent squint
• Eye/s turned upwards - hypertropia
• Eye/s turned downwards - hypotropia
• Corneal reflections, epicanthal folds and large interpupillary distance can lead to pseudo eso/exo
• Look at the corneal light reflex to assess symmetry and eye movements must be assured to be full in both versions (both eyes moving together) and ductions (assesing one eye at a time). Eye movement syndromes and cranial nerve palsies are rare but are required to be in the differential diagnosis.
• Treatment involves conservative, glasses and surgery.

Question 5

Red reflex

Answer 5

• Checked at birth and at 6 week check.
• Urgent referral if absent or abnormal.

Question 6

Leukocoria (white pupil)

Answer 6

• Cataract - most common reason, usually operated on in first few weeks of life
• Retinoblastoma - rare but potentially fatal tumour of the retina, can be treated successfully if presents early.
• Persistent hyperplasia of primary vitreous (PHPV)
• Congenital glaucoma
• Coats disease
• Other (i.e. retinal detachment, toxoplasmosis, uveitis)

Question 7

Eye involvement in genetic or systemic disease

Answer 7

• Lisch nodules in NF1
• Iris transillumination in Albinism
• Dislocated lens in Marfan’s Syndrome
• Anterior uveitis in JIA

Question 8

Nasolacrimal Duct Obstruction (NLDO)

Answer 8

• Incomplete canalisation of NLD is a very common presentation with anxious parents and their new born babies.
• Sticky watery eye with no conjunctivitis.
• Vast majority spontaneously resolve by age 1.
• Can treat with bathing and antibiotics if eye is red/inflammed.

Question 9

Paediatric cataracts

Answer 9

• Bilateral more common than unilateral
• Congenital vs developmental
• Deprivation amblyopia
• Primary
• Secondary:
  
  • Systemic disorders (i.e. chromosomal, metabolic, maternal infections)
  • Ocular developmental disorders (i.e. PHPV)
  • Ocular diseases (i.e. trauma, uveitis, retinoblastoma)
• Indications for surgery:
  
  • Severe (amblyogenic)
  • Fixation instability (nystagmus)
  • VA <6/24 older baby
  • Strabismus
  • Poor visulaisation of fundus
  • Central 3mm opacity
• Post-operative complications:
  
  • Visual axis opacities
  • Glaucoma
  • Strabismus, amnlyopia
  • Inflammation
  • Irregular/rigid pupil
  • Endophthalmitis
  • Retinal detachment (rare)

Question 10

Retinoblastoma

Answer 10

• Most common primary intraocular malignancy in childhood
• Tumour of primitive photoreceptor cells
• No sexual or racial variation
• Rb gene is a TSG located on chromosome 13q14
• RB1 is a recessive oncogene at cellular level
• On presentation:
  
  • EUA
  • Indirect ophthalmascope
  • Ret/Cam +/- fluroscein
  • B scan
  • If optic nerve not seen then MRI
• Classified using IIRC:
  
  • A - small discrete
  • B - low risk
  • C - focal seeding
  • D - diffuse seeding
  • E - high risk
• Treat with cryotherapy and laser photocoagulation, enucleation, radiotherapy and chemotherapy.

Question 11

Retinopathy of prematurity

Answer 11

• Retina not vascularised
• Under certain conditions instead of vascularisation proceeding normally there is growth of new vessels and scarring
• Need 100% O2 from 28-36 weeks
• Acute phase:
  
  • Normal vasculature goes away -> abnormal proliferation
• Chronic phase:
  
  • Late proliferation, retinal detachment and visual loss
• Classified using the ICROP (describes according to zone, extent and stage)
  
  • 1 - Demarcation line
  • 2 - Ridge
  • 3 - Extraretinal fibrovacular proliferation
  • 4 - Partial retinal detachment
  • 5 - Total retinal detachment
• Plus disease includes:
  
  • Venous dilatation or arteriolar tortuosity in at least 2 quadrants
  • Vitreous haze
  • Poor pupil dilatation
  • Vascular engorgement of the iris
• Infants with BW <1501g or GA <32 weeks screened
• Management:
  
  • Cryotherapy to ablate the retina anterior to the ridge
  • Indirect laser photocoagulation - less traumatic, better visual outcome
  • Surgery (for stage 4-5)
  • Intravitreal steroid and anti-VEGF

Question 12

Refractive error

Answer 12

• Myopia - nearsighted
• Hyperopia - farsighted

Question 13

Ophthalmia Neonatorum

Answer 13

• Conjunctivitis within the first month of life
• Organisms commonly acquired from birth canal
  
  • Gonococcal (1-3 days)
  • Chlamydia (4-28 days)
  • HSV (1-14 days)
  • S. aureus, S. pneumoniae, Haemophilus, Pseudomonas (2-5 days)
• Main risk factor is STD from mother
• Investigations:
  
  • Swabs
  • Gram stain, culture and sensitivities
  • PCR/ELISA

Question 14

NAI

Answer 14

• Eye signs suggestive of abuse:
  
  • Retinal haemorrhages
  • Periocular bruising, lid lacerations
  • Unexplained lens dislocation or cataract
  • Unexplained conjunctival or corneal injuries especially in the lower half of the eye