Open Globe Management

Alessandro A. Castellarin, MD; Dante J. Pieramici, MD

Disclosures

Compr Ophthalmol Update. 2007;8(5):111-124. 

In This Article

Diagnostic Techniques in the Evaluation of Ocular Trauma

If more advanced imaging modalities are unavailable, plain radiographs are still valuable for orbital fracture and intraocular/intraorbital foreign bodies. Nonmetallic foreign bodies, such as wood, plastic, or glass, are not easily seen on plain xray films and may be missed.

Computed tomography is now the standard diagnostic test for imaging the traumatized eye and orbit. Current generation computed tomographic machines can detect nonmetallic radiolucent foreign bodies 1 mm in size. Axial sections of the orbit should be no greater than 1.5 mm apart, and, in the case of a suspected small foreign body, overlapping slices may be requested.[7] Bone-free projections are used to detect small radiolucent foreign bodies (Figure 1). Computed tomography is usually available in most hospitals; it is fast and less expensive than magnetic resonance imaging (MRI).

Magnetic resonance imaging can detect a wide variety of vegetable, plastic, glass, and radiolucent foreign bodies in the eye. However, MRI is not useful, and is potentially harmful, in identifying magnetic foreign bodies, and may not be readily available preoperatively. Magnetic resonance imaging has certain advantages, such as the ability to generate axial, coronal, and sagittal views simultaneously (eliminating the need for patient repositioning), an image quality superior to that provided by CT for soft tissues and nonmagnetic IOFBs (wood, glass), and its availability for pregnant patients.

Short TI Inversion Recovery (STIR) technique can be useful. It is another fat suppression technique that is less sensitive to the alterations of the magnetic field produced by air or metal, which cause fat suppression failure.

Ultrasonography is reliable in detecting choroidal/scleral ruptures, vitreous incarceration choroidal detachment (can differentiate between serous and hemorrhagic), vitreous hemorrhages, posterior vitreous separation, retinal tears and areas of vitreoretinal adhesion, IOFBs, and retinal detachment. Ultrasonography is less expensive than CT scan and allows outstanding resolution with real-time images of the eye and, to a lesser extent, the orbit. Prior to closure of the globe, the use of ultrasonography can be problematic, as pressure on the globe can lead to additional injury.

Electroretinography (ERG) can be useful in gauging the visual potential of the injured eye in patients who are unable to communicate with the examiner (e.g., patients who have cognitive impairment or patients who are of a young age). The ERG may also be used to assess the level of retinal degeneration in cases of chronic metallic intraorbital foreign bodies.

The Ocular Trauma Classification Group has developed a classification system based on the Birmingham Eye Trauma Terminology, and injured eyes are categorized by four parameters:

Type (based on the mechanism of trauma): rupture, penetrating (Figure 2), perforating, IOFB, and mixed.

Grade (based on visual acuity at presentation): > 20/40, 20/50–20/ 100, 19/100–5/200, 4/200–light perception, and no light perception.

Pupil: positive afferent pupillary defect, and negative afferent pupillary defect.

Zone (based on the extent of the injury): (I) cornea and limbus, (II) limbus to 5 mm posterior into sclera, and (III) > 5 mm.

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