leukoria

Question 1

what is leukoria?

Answer 1

White-coloured pupillary reflex when ophthalmoscope is shone at the pupil

Question 2

what are the lens causes of leukoria?

Answer 2

Congenital cataract

Question 3

what are the vitreous causes of leukoria?

Answer 3

Persistent fetal vasculature (PFV)

Question 4

what are the retina/ choroid causes of leukoria?

Answer 4

• Congenital/developmental: chorioretinal coloboma
• Exudation: Coat’s disease
• Infection: Toxocara (roundworm parasite)
• Tumours: retinoblastoma (RB)
• Others: retinal detachment, retinopathy of prematurity (ROP)

Question 5

where is the mutation in retinoblastoma?

Answer 5

Mutation in both alleles of the Rb1 tumour suppressor gene, on short arm of chromosome 13 (13q14.2)

Question 6

what are the symptoms of retinoblastoma?

Answer 6

• Visual inattention
• Strabismus
• Painful eye and/or swollen eyelids (can mimic orbital cellulitis)
• +/- FHx of retinoblastoma

Question 7

what are the signs of retinoblastoma?

Answer 7

• Leukocoria
• Rubeosis iridis (abnormal blood vessels on iris)
• Raised IOP
• Retinal detachment
• Retinal mass

Question 8

where can the retinal mass in retinoblastoma extend?

Answer 8

Endophytic: grows from the retina inward toward the vitreous cavity 🡪 white hazy mass with obscuration of retinal blood vessels – tumour is friable, can seed the vitreous cavity and anterior chamber (pseudo-hypopyon)

Exophytic: grows from the retina outward into the subretinal space 🡪 exudative retinal detachment (exudative RD) – can lead to subretinal seeding

Diffusely infiltrative: relatively flat infiltration of retina by tumour cells w/o obvious mass, grows intraretinally 🡪 causes ischaemia 🡪 iris neovascularisation (rubeosis iridis)

Question 9

what are the causes of congenital cataract?

Answer 9

Idiopathic

Familial/hereditary (positive FHx)

Local ocular disease or developmental anomaly e.g. anterior segment dysgenesis, persistent fetal vasculature

Systemic disease (usually bilateral cataracts)

• Chromosomal abnormalities, e.g. Down syndrome (trisomy 21)
• Intrauterine infections (TORCH infections)
• Metabolic diseases, e.g. galactosaemia

Question 10

what is the treatment for congenital cataract

Answer 10

To rule out systemic causes

To provide clear retinal image

• Mild cataract/good vision 🡪 correct refractive error
• Severe cataract/impaired vision 🡪 cataract surgery (removal + IOL)

To treat associated amblyopia: Patching, atropine penalisation

Question 11

what is persistent fetal vasculature?

Answer 11

Reflects failure of regression of primary vitreous during fetal development

Question 12

what is the clinical presentation of persistent fetal vasculature?

Answer 12

• Leukocoria
• Mass behind lens, a/w cataract
• Dense white membrane (fibrovascular stalk) extending anteriorly from optic disc

Question 13

what is the pathophysiology of coat disease?

Answer 13

Exudative retinitis/retinal telangiectasia (congenital, non-hereditary)

Telangiectatic and aneurysmal retinal vessels

• Pericyte loss 🡪 formation of aneurysms 🡪 breakdown of endothelial blood-retinal barrier 🡪 leakage into the vessel wall – can develop exudative retinal detachment
• Extensive exudation from vessels 🡪 gives off leukocoria

Question 14

what is retinochoroidal coloboma?

Answer 14

• Failure of closure of embryonic fissure
• Large retinochoroidal coloboma gives off leukocoria
• Coloboma may also involve optic nerve, iris, eyelid