Question

A 4-month-old infant with known Down syndrome presents with hypotonia, upslanting palpebral fissures, umbilical hernia, and poor visual tracking. On examination, there is evidence of visual inattention. What is the next best investigation?

• A. Visual Evoked Potential (VEP)
• B. Brain MRI
• C. Fundus examination
• D. TORCH screening

Hint:

Down Syndrome Ophthalmology Guidelines:
- All infants with Down syndrome must undergo red reflex examination at birth and formal ophthalmic/fundus examination within the first 6 months of life.
- Common ocular anomalies: Congenital cataracts, refractive errors, strabismus, Brushfield spots, and tear duct stenosis.

Answer 1

The Correct Option is C

Concept:
Infants with Down syndrome (Trisomy 21) have a markedly increased incidence of structural and refractive ophthalmic disorders, including congenital cataracts, infantile glaucoma, strabismus, nystagmus, Brushfield spots, and retinal anomalies.
Visual inattention in an infant with Down syndrome requires immediate evaluation of the optical media, retina, and optic nerve to prevent amblyopia.
Explanation:
• Ocular disorders occur in up to 60% to 70% of children with Down syndrome, with congenital or infantile cataracts and retinal/optic nerve abnormalities being major causes of early preventable visual impairment.

• A comprehensive dilated fundus and red reflex examination by an ophthalmologist allows direct visualization of the clarity of the ocular media (cornea, lens, vitreous) and structural integrity of the retina, fovea, and optic disc.

• Congenital cataracts or optic nerve colobomas/hypoplasia must be identified and addressed within the critical early visual development window (first 3--6 months) to avoid irreversible stimulus-deprivation amblyopia.

• Visual Evoked Potential (VEP) evaluates the functional integrity of the visual pathway from the retina to the visual cortex but does not provide direct anatomic diagnosis of treatable structural ocular lesions.

• Brain MRI and TORCH screening are low-yield initial tests in a known Down syndrome infant presenting primarily with visual inattention when basic ocular examination has not yet been performed.
Final Answer:
A direct fundus and red reflex examination is the first-line and most critical investigation to detect treatable ocular and retinal abnormalities causing visual inattention in Down syndrome.