The red reflex test
- Examination
Shining an ophthalmoscope into both pupils from arm's length shows two matching red glows. A missing, white or uneven reflex in a child is referred urgently.
What it is
The red reflex is the orange-red glow of light reflected from the fundus through clear media. Comparing both eyes at once (the Brückner test) screens newborns and children for anything that blocks or distorts the light path: cataract, retinoblastoma, retinal detachment, vitreous haemorrhage, large refractive differences and strabismus. It is a quick, cheap test that every doctor who examines children should do.
Normal values and scales
- Normal: two bright, equal, orange-red reflexes; darker-pigmented eyes give a darker red.
- Absent or dull reflex: cataract or another opacity of the media.
- White reflex (leukocoria): retinoblastoma until proven otherwise.
- One reflex brighter than the other: strabismus or a large difference in refraction (risk of amblyopia).
- Recommended at birth and at every routine child health visit.
How it is done
- Dim the room lights; dilation is not needed for screening.
- Set the direct ophthalmoscope to zero and stand at about an arm's length from the child.
- Shine the light so it covers both pupils at once and look through the ophthalmoscope.
- Compare colour, brightness and size of the two reflexes, and look for dark spots or white areas.
- Note where the corneal light reflections fall: asymmetry suggests strabismus.
- Record the result; repeat at each well-child visit.
How to interpret it
- A dense congenital cataract must be operated on within the first weeks to avoid permanent amblyopia, so the newborn exam matters.
- A white reflex in a family photo with flash is a valid reason for referral even if the office test is normal.
- In adults, a dull reflex is mostly cataract or vitreous haemorrhage.
Next step / Initial management
- Any abnormal, absent or asymmetric reflex in a child: urgent paediatric ophthalmology, seen within days.
- Leukocoria: follow the leukocoria pathway (retinoblastoma).
- Normal reflex but parental concern or a family history of retinoblastoma or congenital cataract: refer for a dilated exam.
- Document each test in the child health record.
Test yourself
Think of the answer, then tap the question to see it.
How is the red reflex test done in a child?
In a dim room, with the ophthalmoscope at arm's length, lighting both pupils at once and comparing the two reflexes.
What does an absent red reflex in a newborn suggest?
A congenital cataract or another opacity, which needs urgent ophthalmology.
When should the red reflex be checked?
At birth and at every routine child health visit.
Connections
Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once.
Sources: Red Reflex (StatPearls Publishing (NCBI Bookshelf), 2023); Leukocoria (StatPearls Publishing (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.