Paeds Ophthalmology

Question 1

What is strabismus?

Answer 1

A horizontal or vertical misalignment of visual axes

Question 2

What is esotropia?

Answer 2

Horizontal misalignment of visual axes with convergence (in-turning) of the affected eye

Question 3

What is exotropia?

Answer 3

Horizontal misalignment of visual axes with divergence (out-turning) of the affected eye

Question 4

Hypertropia and hypotropia

Answer 4

hyper= upward and hypo = downward misalignment of the eye

Question 5

Prevalence of strabismus

Answer 5

Esotropia prevalence approx 2% in childhood

Exotropia prevalence is less than 1%, (1/3 as prevalent as esotropia)

Question 6

Causes of Esotropia

Answer 6

Infantile esotropia - assoc latent nystagmus, presents first 6m of life, large angle deviation
Accommodative esotropia: result of hypermetropia - exaggerated convergence, presents 1-2y, correcting refractive error will correct strabismus
Acquired non-accommodative esotropia: present 3-5y, no refractive errors, 10% assoc with neuro abnormalities
Neuro: CN 6 palsies most common (congenital or acquired)

Question 7

Causes of exotropia

Answer 7

Infantile exotropia: first 6m
Exophoria/intermittent exotropia: eye tends to drift but normally maintains normal alignment, compensation sometimes fails

Question 8

Clinical examination of a strabismus

Answer 8

Corneal light reflections: in a normal eye will be central and symmetrical
Cover test: covering the apparently normal eye - other eye will shift to take up fixation if it was misaligned
?nystagmus etc.
?Refractive error

Question 9

Masquerades of strabismus (psedostrabismus)

Answer 9

Prominent epicanthal folds in infants (obscures nasal sclera so appears to be misaligned)
Telecanthus (larger distance between medial canthi than normal)
Hypertelorism (larger distance between eyes themselves than normal - bony path usually)
Angle Kappa (difference between pupillary and visual axis e.g. retinopathy of prematurity - peripheral retinal scarring - temporal displacement of maculae - fixation point of macula does not coincide with axis of pupil - appears exotropic) - cover test will be normal

Question 10

Complications of untreated strabismus

Answer 10

?may miss an underlying ophthal or neuro problem

Ambylopia in 50-60% - significant vision loss

Question 11

Management of strabismus

Answer 11

Glasses (in hypermetropic accommodative esotropia)
Eye exercises
Surgical correction - recession or resection of extraocular muscles as indicated
Aim for early realignment ASAP to prevent complications

Question 12

Dye used for assessing corneal abrasions/ulcers

Answer 12

Fluroscein

Question 13

Possible presentations of retinoblastoma

Answer 13

Strabismus
Poor vision
Known family history or retinoblastoma
Leukocoria (screening or parents may bring in odd photos)

Question 14

Imaging in retinoblastoma

Answer 14

Ultrasound or MRI to show intralesional calcification typical of retinoblastoma

Question 15

Sporadic v hereditary retinoblastoma

Answer 15

Sporadic: 2 separate mutations of Rb gene within a single retinoblast cell - ALWAYS UNILATERAL
Hereditary: 1st mutation occurs in germ cell (usually sperm), 2nd occurs within retinoblast - this more likely to be bilateral (not always though)

Question 16

Poor prognostic factors of retinoblastoma

Answer 16

delay in diagnosis
larger tumour 
older age
optic nerve involvement
extraocular extension
(5 year survival is 98%)

Question 17

Management options for retinoblastoma

Answer 17

Photocoagulation
Cryotherapy
Radioactive plaques
External beam radiotherapy
Chemotherapy
Surgery (e.g. Enucleation - removal of eye)

Suggest family screening, especially if bilateral

Question 18

Ophthalmia neonatorum causes

Answer 18

Bacterial:
Chlamydia (40%, D5-14)
N Gonorrhoea (D2-5) - severely swollen eyelid
Chemical inflammation (6-8h post chemical, resolves within 48)
Viral - HSV (

Question 19

Complications of ophthalmia neonatorum

Answer 19

Corneal ulceration - perforation - BLINDNESS
pneumonia (chlamydia)
Sepsis

Question 20

Epidemiology of nasolacrimal duct obstruction

Answer 20

6% prevalence in newborns
Most common cause of persistent tearing/ocular discharge in infants/kids
Spontaneous resolution by 6m in 90%
Unlikely to spontaneously resolve after 12m

Question 21

Presentation of nasolacrimal duct obstruction

Answer 21

Chronic or intermittent tearing + debris on eyelashes
Conjunctiva/eyes are not inflamed or erythematous
May be mild erythema of lower lid
Dye disappearance test (if asymptomatic at time of assessment) - dye will not be drained after 5 minutes

Question 22

Management of nasolacrimal duct obstruction

Answer 22

Lacrimal sac massage (downward pressure, 2-3sec, 2-3 times per day)
Lacrimal duct probing under GA if not resolved by 12m

Question 23

Orbital cellulitis v periorbital cellulitis (anatomy and presentation)

Answer 23

Orbital is post-septal, periorbital is pre-septal
ORBITAL: systemically unwell, proptosis, redness of eye itself, impaired vision, ophthalmoplegia/pain on eye movements, pupil abnormality
PERIORBITAL: just erythema and swelling around eye - none of the above

Question 24

Presentation of orbital cellulitis

Answer 24

acutely red and swollen eye

Proptosis, ophthalmoplegia, pain on eye movement, vision impairment, pupil abnormality, systemically unwell

Question 25

Complications of orbital cellulitis - how to diagnose

Answer 25

Subperiosteal abscess Orbital abscess (CT or MRI of orbit) Extraorbital extension

Question 26

Management of orbital cellulitis

Answer 26

Urgent referral to ophthalmology IV antibiotics: Cefotaxime IV 50mg/kg up to 2g, 8-hrly 3-14 days (depends on response) Followed by: Oral amoxycillin/clavulanate BD for a further 10 days

Question 27

Aetiology and Pathogens likely to cause orbital cellulitis

Answer 27

Most commonly a complication of bacterial rhinosinusitis (though it is not a common complication) - particularly ethmoid involvement Microbiology: strep anginosus or strep pneumoniae, staph aureus (including MRSA)

Question 28

Epidemiology of congenital glaucoma

Answer 28

1/10,000 live births bilateral in 60% *onset may be asymmetric onset of signs and symptoms at birth in 40% (by 12m in 85%) Usually a sporadic disease (not inherited)

Question 29

Presentation of congenital glaucoma

Answer 29

``` chronic or intermittent tearing photophobia blepharospasm (involuntary tight closure of lids) Large/asymmetrical cornea corneal clouding conjunctival injection optic nerve cupping Occular enlargement (buphthalmos) Younger kids: more likely odema and haze, Older kids: more likely corneal and ocular enlargement ```

Question 30

Management of congenital glaucoma

Answer 30

urgent ophthalmology referral Medical: drops to reduce IOP Surgical intervention (cutting of angular trabecular network to deepen angle recess or creating an opening in Schlemm's canal) Regular and life-long follow up will be required

Question 31

Associations with congenital glaucoma

Answer 31

Congenital rubella | Sturge-Weber syndrome

Question 32

Causes of congenital cataracts

Answer 32

Hereditary (autosomal dominant - recessive or X-linked less common) Metabolic disease (e.g. galactosaemia, hypothyroid) Syndromes (e.g. T21) Congenital infections (e.g. Rubella) Idiopathic - esp if unilateral

Question 33

Presentation of congenital cataract

Answer 33

``` Parents may be able to see cataract with naked eye if anterior portion Poor vision - abnormal behaviour Delayed development Nystagmus or Strabismus Photophobia Asymmetric red refelx/leukocoria ```

Question 34

Management of congenital cataract

Answer 34

Refer to ophthalmologist Surgical removal based on size and effect on vision - generally try to perform within first few months of life if identified

Question 35

Coloboma

Answer 35

defect in the iris which appears like a prolapsed pupil "Keyhole pupil"