Ultrasound biomicroscopy as a tool for detecting and localizing occult foreign bodies after ocular trauma

Abstract

Objective To show the utility of ultrasound biomicroscopy (UBM) in imaging small ocular foreign bodies of the anterior segment. Design Retrospective case series. Participants Twelve eyes of 12 consecutive patients evaluated in the emergency department or referred to specialty services at 1 institution between August 1994 and November 1997 were examined. Intervention Ocular ultrasound biomicroscopy was performed. Main outcome measures Detection and localization of an ocular foreign body were measured. Results An intraocular or superficial foreign body was detected by UBM in 9 (75%) of 12 eyes. The foreign body was classified as corneal in two eyes, subconjunctival in two, intrascleral in three, and intraocular in two eyes. The foreign body was not visible by ophthalmic physical examination in seven of the nine eyes with a confirmed ocular foreign body. In the remaining two eyes, UBM was used to determine the depth of a visible foreign body. In three of the eyes with a confirmed foreign body, computed tomography and/or contact B-scan ultrasonography was obtained and failed to show a foreign body. Six of the foreign bodies were nonmetallic. Conclusions Clinical detection of ocular foreign bodies after trauma can be hindered by small size, haziness of the optical media, poor patient cooperation, or hidden location. Ultrasound biomicroscopy is a valuable adjunct in the evaluation of suspected ocular foreign bodies, especially in cases involving small, nonmetallic objects.