illnesses, including varicella As with exotropia of neurogenic origin, it would be more likely to have other branches of the third cranial nerve involved with other findings Another type of vertical eye muscle imbalance, skew deviation, can be the presenting sign of a midbrain lesion Ophthalmology consultation can be helpful in deciding whether MRI is appropriate Hypotropia can be caused by an orbital roof fracture with superior hematoma that pushes the eye down Alternatively, hypertropia from a deficiency of downward gaze due to tethering of the superior rectus muscle in an orbital roof fracture can also occur uncommonly Orbital roof fracture is an emergent condition Neuroradiologic evaluation of the brain and the orbits, including coronal views, must be obtained to rule out communication between the orbit and the intracranial cavity Pulsating proptosis is a particularly ominous sign indicating direct contact between the intracranial and orbital compartments Traumatic hypotropia most commonly results from orbital floor blowout fractures ( Figs 28.4 and 28.8 ) Enophthalmos may be observed, and there may be associated numbness in the distribution of the infraorbital nerve as it innervates the ipsilateral infraorbital and malar region Orbital lesions, including those that may have extended from the intracranial cavity, may push the eyeball downward and prevent it from looking upward Thyroid eye disease also can cause hypotropia due to tightening of the inferior rectus In summary, prompt evaluation and treatment by an ophthalmologist is warranted for all children presenting with acute strabismus as these patients are at risk for visual loss from amblyopia Emergent evaluation is needed if the eye movements are limited by paralysis or restriction of the extraocular muscles Suggested Readings and Key References Abramson DH, Beaverson K, Sangani P, et al Screening for retinoblastoma: presenting signs as prognosticators of patient and ocular survival Pediatrics 2003;112(6 pt 1):1248–1255 Chapter 8: Pediatrics In: Bagheri N, Wajda BN, eds The Wills Eye Manual— Office and Emergency Room Diagnosis of Eye Disorders 7th ed Philadelphia, PA: Wolters Kluwer; 2017:177–203 Donahue SP Clinical practice Pediatric strabismus N Engl J Med 2007;356:1040–1047 Oppenheimer AJ, Monson LA, Buchman SR Pediatric orbital fractures Craniomaxillofac Trauma Reconstr 2013;6(1):9–20 Ticho BH Strabismus Pediatr Clin North Am 2003;50(1):173–188