Chapter 46 Ophthalmologic Emergencies
1 What is an afferent pupillary defect?
The pupillary light reflex is a reflex arc through the midbrain involving crossover innervation. It is assessed with the swinging light test: Shining a light in one eye should result in constriction of both pupils. No change in pupillary size should be noted when the light swings toward the other pupil. If a patient has an afferent pupillary defect, both pupils dilate when the light swings to the affected eye. The abnormal pupil, called a Marcus Gunn pupil, can result from retinal artery or venous occlusions, retinal detachment, tumors, or ischemic optic neuropathy.
Wright KW: Pupil and iris abnormalities. In Pediatric Ophthalmology for Pediatricians. Baltimore, Williams & Wilkins, 1999, pp 139–149.
2 What is the Bruckner test? How is it performed?
The Bruckner test is a simultaneous bilateral red reflex test that elicits both a corneal light reflex and a red reflex. View the patient’s eyes from about 2 feet away with a broad beam of light that encompasses both eyes. You should see both a red reflex and a small white light reflex in each eye. The key to a normal examination is symmetry. An absent or dull red reflex may indicate vitreous hemorrhage, cataract, hyphema, opacity of the cornea, enophthalmos (backward displacement of the globe in the orbit), or misalignment of the globe.
Garcia SE, Hickey R, Santamaria JP: Pediatric ocular trauma. Pediatr Emerg Med Rep Oct:87–98, 1998.
3 What is the differential diagnosis of papilledema?
Papilledema is caused by anything that increases intracranial pressure. It is usually bilateral.
4 List and describe briefly the four types of orbital wall fractures
Medial wall fractures are caused by blows to the bridge of the nose. Physical findings include orbital emphysema, epistaxis, depressed nasal bridge, and enophthalmos (sunken eye). Excessive tearing may be seen if the lacrimal system is disrupted.
Orbital floor (“blowout”) fractures result when an object larger than the orbital diameter, often in the inferior lateral orbital rim, impacts the bony orbit. The impact causes increased intraorbital pressure and rupture of the orbital floor, which often is associated with prolapse of orbital contents into the maxillary sinus. Entrapment of the inferior rectus muscle causes limitation of upward gaze. Infraorbital nerve injury causes hypesthesia of the ipsilateral cheek and upper lip. Traumatic optic neuropathy can complicate an orbital floor fracture with immediate loss of vision and afferent pupillary defect.
Superior wall (orbital roof) fractures are less common than medial or floor fractures but they are potentially life-threatening. They may be associated with central nervous system injury, pneumocephalus, or intracranial foreign body. Potential complications include brain abscess and meningitis. Findings include rhinorrhea (cerebrospinal fluid leak) and superior and lateral subconjunctival hemorrhage.
Tripod fractures involve the zygomatic arch and its lateral and inferior orbital rim articulations. Examination findings are similar to those of orbital floor fractures, along with limitation of mandibular movement and trismus.
Garcia SE, Hickey R, Santamaria JP: Pediatric ocular trauma. Pediatr Emerg Med Rep Oct:87–98, 1998.
5 How are orbital fractures managed?
Therapeutic interventions for any orbital fracture include antibiotic prophylaxis, nasal decongestants, and ice packs; some fractures may require surgical intervention. Computed tomography of the orbit, including axial and coronal views, is useful in diagnosis and delineating the extent of injury. All patients should be cautioned to avoid blowing their nose. Consultation with an ophthalmologist is indicated.
Levin AV: Eye trauma. In Fleisher GR, Ludwig S (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2000, pp 1485–1496.
6 What is the difference between monocular and binocular diplopia?
Binocular diplopia resolves when either eye is covered. With monocular diplopia, double vision is present even when one eye is covered.
7 What causes binocular and monocular diplopia?
The causes of binocular diplopia include blowout fracture, traumatic cranial nerve palsies, iris injuries, inflammation, neoplasm, and strabismus. The causes of monocular diplopia include uncorrected refractory error, cataract, displaced lens, and conversion disorder.
8 What are “raccoon eyes”? What causes them?
Raccoon eyes result from eyelid ecchymoses, which classically are associated with basilar skull fractures. Subcutaneous bleeding occurs in the area around the orbits.
Full access? Get Clinical Tree
