Ultrasonography and ocular trauma [abstract]

ABSTRACT

Blunt or perforating trauma can cause considerable damage to both the anterior and posterior segment of the eye. Since the media are often opaque following trauma, the extent of the damage may be difficult to assess with routine examination. Ultrasonography can reveal hidden pathology and is often helpful in deciding upon the proper line of treatmemt. In post-contusional trauma without an open globe, full ultrasonographic investigation, including immersion techniques, can be performed. On the contrary, after perforation lesions, an exploratory B-scan can be used for locating an intraocular foreign body in addition to gross assessment of the damage. The ultrasonographic examination can only be continued in further detail after primary closure of the wound. When an x-ray of the orbit reveals the presence of an intraocular foreign body B-mode ultrasonography is superior to the Comberg-Pfeiffer method and computer tomography for precise localizations of the object and for detection of collateral damage. Transpalpebral echography or scans with the probe directly applied to the eye, at significantly reduced sensitivity levels (-20 or -30 dB) are the methods of choice for tracing a foreign body in the posterior segment or orbit. Lowering the sensitivity settings will also improve the accurate location of the foreign body. The immersion technique is used when the foreign body is located anteriorly in the eye, providing that the entry wound is closed. In particular after contusional injuries, ultrasound biomicroscopy (UBM) can be used for detailed observations of the cornea, anterior lens, chamber angle and ciliary body. Recession of the angle, subluxation of the lens and dialysis of the iris or ciliary body can be diagnosed with relative ease. When vitrectomy is indicated either as a primary or secondary procedure following ocular trauma, ultrasonography is essential in the preoperative evaluation. It will help in deciding upon the length of the preoperative period, the estimated duration of the operation and the appropriate surgical approach. A full anatomical analysis can be obtained by systemically assessing the biometric, topographic, kinetic and quantitative characteristics of the various parts of the eyes. The most commonly occuring ocular pathology following trauma, along with the most suitable diagnostic ultrasonic techniques will be discussed in detail and are depicted in the table. (AU)