In a child with refractory strabismus, what test should be obtained?

• A. cranial XR
• B. head CT
• C. Fundoscopic exam
• D. MRI

Answer: (D)

When strabismus in a child does not improve with standard treatment, look for an underlying neurologic or orbital problem. The test of choice is MRI of the brain and orbits with contrast. MRI provides superior soft-tissue detail of the brain, cranial nerves, optic pathways, and extraocular muscles, allowing detection of tumors, demyelinating or vascular lesions, and other intracranial or orbital abnormalities that could be driving misalignment. It avoids ionizing radiation and can be performed with sedation in children if needed, making it the most informative and safest option for this scenario.

Cranial X-ray is outdated and insensitive for soft-tissue and neural structures. Head CT, while faster, involves radiation and offers less detailed evaluation of soft tissues and subtle intracranial pathology. A fundoscopic exam can reveal signs like papilledema or intraocular tumors but does not identify underlying intracranial causes of refractory strabismus.