Paediatric eye examination and red-reflex assessment — formative SAQs

SAQ 1 (10 marks)

A six-week-old infant is brought for a routine check. The red-reflex test shows a dense white reflex in the right eye and a normal red reflex in the left. The parents had not noticed anything and feel the baby sees normally. ^[4]

Question: (a) Describe the correct technique for the red-reflex test and explain the physiology of the normal reflex. (b) Give a prioritised differential diagnosis for this finding and state the immediate management. (c) Outline how you would communicate the result to the parents. (10 marks) ^{[4] [6]}

Model answer

(a) Technique and physiology (3 marks). Perform the test in a dim room, with the direct ophthalmoscope on the largest, brightest spot at zero or low magnification, standing about an arm's length away (roughly 30 to 45 centimetres), and examine both pupils together so the two reflexes can be compared side by side (the Bruckner test); repeat at a couple of distances and gaze positions and document the finding for each eye. The normal orange-red reflex is light that has passed through the clear cornea, aqueous, lens and vitreous, reflected off the retina and the blood-rich, melanin-rich choroid, and returned through the same clear media — so the reflex tests the clarity of the whole visual axis. ^{[4] [1]}

(b) Differential and immediate management (5 marks). A dense white reflex in an infant is leukocoria, a pale lesion in the visual axis reflecting light back white. The differential is led by the two that threaten sight or life: congenital or developmental cataract (common, treatable, time-critical for amblyopia) and retinoblastoma (the primary intraocular malignancy of childhood, which can be fatal beyond the eye). Next come persistent fetal vasculature (a fibrovascular stalk and retrolental mass, usually unilateral and microphthalmic from birth), Coats disease (exudative retinal detachment from retinal telangiectasia), ocular toxocariasis, retinal detachment (including from trauma or shaken-impact injury) and retinal or choroidal coloboma. The immediate management is urgent ophthalmology referral, the same day for a suspected serious lesion; apply no drops, ointment or home remedy before specialist review; document the finding for each eye; and arrange the dilated fundus examination, ultrasound for calcification, and examination under anaesthesia as the ophthalmology team directs. Do not order blood tests in lieu of referral. ^{[3] [6]}

(c) Communication (2 marks). Explain the urgency in plain language without using alarming diagnostic labels — frame it as an abnormal screening finding that needs an eye specialist to look at today, not as a suspected tumour. Tell the parents exactly when and where to be seen, what the specialist will do (dilate the pupil and examine the back of the eye), what would bring them back sooner, and the safety-net of confirming the appointment was kept. Avoid the dual pitfalls of false reassurance ('it is probably nothing') and premature labelling ('this could be cancer'). ^{[4] [6]}