The Utility of Bedside Ultrasound in the Detection of a Ruptured Globe in a Porcine Model

BACKGROUND: Recent case reports have shown that ultrasonography can be used to diagnose ocular pathology in an emergency setting. Ultrasound may be especially useful when periorbital edema and pain interfere with the examination of the post-traumatic eye. OBJECTIVE: This study evaluated the ability of emergency physicians to detect a ruptured globe in an ex-vivo porcine model. METHODS: Following a brief training lecture, 15 emergency medicine residents and 4 emergency medicine attending physicians used ultrasonography to evaluate 18 porcine eyes, randomized as normal, ruptured, or completely devoid of vitreous humor. The consequences of ultrasound applanation with this method were evaluated by measuring intraocular pressure changes with and without a 1mm clear plastic shield. RESULTS: Our study participants were able to identify abnormal eyes with a sensitivity of 79% (95% CI 73% to 84%) and a specificity of 51% (95% CI 41% to 61%). Intraocular pressure increased 5% with ultrasound applanation, though with a 1mm thick plastic shield there was no measurable change. CONCLUSIONS: Ultrasound imaging may be a future modality to be used by trained emergency physicians to expedite the identification of a rupture globe, but it is unlikely to replace more definitive imaging techniques. The use of a clear plastic barrier in this porcine model prevents an increase in intra-ocular pressure without affecting image quality, and should be used in any future studies on this method.