Intraorbital Foreign Bodies
Orbital CT is the study of choice to localize an orbital foreign body (Fig 6-6). An inorganic foreign body may be difficult to visualize on CT and is better observed on magnetic resonance imaging (MRI). However, MRI should be avoided if there is a possibility that the foreign object is ferromagnetic. Orbital ultrasonography may be helpful for foreign bodies positioned more anteriorly. Treatment of orbital foreign bodies initially involves culturing the wound (or the foreign body if it is removed) and administering antibiotics. Foreign bodies should be removed if they are composed of vegetable matter or if they are easily accessible in the anterior orbit. If an embedded foreign body causes an orbital infection that drains to the skin surface, it is sometimes possible to locate the object by surgically following the fistulous tract posteriorly. In many cases, objects can be safely observed without surgery if they are inert and have smooth edges or are located in the posterior orbit. Pellets from BB guns are common intraorbital foreign bodies and are usually best left in place. MRI can be safely performed with a BB pellet present in the orbit.
Figure 6-6 Intraorbital foreign body. Coronal CT demonstrates a metallic, extraconal foreign body of the left orbit resting along the zygomatic bone that is consistent with a pellet from a BB gun. This type of foreign body may be observed without surgery.
(Courtesy of M. Reza Vagefi, MD.)
Ho VH, Wilson MW, Fleming JC, Haik BG. Retained intraorbital metallic foreign bodies. Ophthalmic Plast Reconstr Surg. 2004;20(3):232–236.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.