Ocular trauma is an important cause of visual impairment worldwide. Ocular globe trauma can be classified as follows (terminology based on the Birmingham Eye Trauma Terminology System):
This chapter focuses on posterior segment injuries; therefore, lamellar lacerations and superficial foreign bodies are not discussed here.
Microsurgical techniques have improved the ability to repair corneal and scleral lacerations, and vitrectomy techniques allow management of severe intraocular injuries (see Chapter 20 in this volume). Ocular trauma is also discussed in BCSC Section 6, Pediatric Ophthalmology and Strabismus; Section 7, Oculofacial Plastic and Orbital Surgery; and Section 8, External Disease and Cornea.
Evaluation of the Patient After Ocular Trauma
In the initial evaluation of an ocular injury, the clinician should try to determine whether the injury is closed globe or open globe, and whether an intraocular foreign body (IOFB) is present. The evaluation includes obtaining a complete history, or as complete as possible under the circumstances, which is crucial before a patient with ocular trauma is examined (Table 18-1), and performing a thorough examination. During the examination, caution is required to avoid exacerbating the damage; for example, attempting to pry open the eye of an uncooperative patient is inadvisable. If possible, the clinician should measure the visual acuity of each eye separately and evaluate the pupils for an afferent pupillary defect. To the extent possible, external, slit-lamp, and fundus examination should be performed and intraocular pressure (IOP) should be measured. Severe chemosis, ecchymosis, eyelid edema, low IOP, the presence of an entrance wound, iris damage or incarceration, cataract, or other anterior segment pathology may suggest an ocular rupture or laceration. Normal IOP and/ or absence of findings on examination do not exclude an occult penetration of the globe.
Table 18-1 Important Questions to Ask in Cases of Ocular Trauma
If an open-globe injury is suspected but cannot be confirmed based on findings, or if lack of patient cooperation prevents a thorough examination in the clinical setting (eg, when examining a child), a thorough examination with possible surgical exploration should be performed under general anesthesia in the operating room. Optimally, the patient’s consent should be obtained for immediate repair following this examination and surgical exploration.
Ocular imaging can help assess the status of the injured eye and facilitate detection of an IOFB, particularly in the presence of media opacities. In the acute setting, the 2 most helpful imaging systems are ocular ultrasonography (B-scan) and computed tomography (CT) of the eye and orbits. When an ocular ultrasound examination is performed, care must be taken to avoid causing ocular compression, which may lead to expulsion of intraocular matter. It is advisable to perform the ultrasound through the patient’s closed lids, aided by copious amounts of ultrasound gel. B-scan ultrasonography can be particularly helpful in detecting nonradiopaque IOFBs, such as wood and plastic. Signs of a scleral rupture that are visible on ultrasonography include the entrapment of vitreous strands into the rupture site. Intraocular air may cause image artifacts that complicate the interpretation of ultrasonography.
Bone-free plain-film x-ray studies may be helpful, but these are less sensitive than ultrasonograms for detecting smaller IOFBs. CT is very helpful in detecting radiopaque IOFBs; however, very dense IOFBs may introduce image artifacts that cause them to appear larger than they really are, making exact localization difficult. Although magnetic resonance imaging (MRI) is not usually used in the acute setting, it can be helpful in detecting detailed ocular anatomy and in identifying the presence and location of IOFBs, including those that are not radiopaque. However, MRI should be used only after the presence of ferromagnetic foreign bodies has been definitively ruled out, due to the possibility that the magnetic field may move such foreign bodies, causing additional damage.
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.