Efficiency of different imaging methods in detecting ocular foreign bodies.

Background: Ocular foreign bodies (OFBs) are a relatively common occurrence in ocular injuries, and a severe risk factor for vision disorders. They are notoriously challenging to identify and localize precisely to allow surgical removal, even with the most recent technological advancements.
Purpose: To compare the efficiency of different imaging methods in detecting and localizing OFBs.
Methods: We conducted a retrospective analysis of the medical records of patients with OFBs, detected by ultrasound biomicroscopy (UBM) and confirmed during surgery. Patients who presented to our medical center between January 2016 and January 2022 and also underwent computed tomography (CT), X ray, and/or ocular B-scan ultrasonography (B-scans) were selected.
Results: This study included 134 patients with a history of ocular trauma and OFBs (mean age: 47.25 years, range: 8-78). The mean time interval from injury to UBM examination was 36.31 months (range: 0.2-120 months). Most OFBs were metallic (51.82%) or plant-based (25.37%); 22.39% of them were located in the sclera, 26.87% in the anterior chamber, and 23.88% in the ciliary body and iris. OFBs ranged in size from 0.10 to 6.67 mm (mean: 1.15 ± 1.10 mm). B-scans identified OFBs in 37 of the 119 patients examined (31.09%); CT in 52 of 84 patients (61.90%); and radiography in 29 of 50 patients (58.00%). Univariate and multivariate analyses determined that both CT and radiography showed low detection rates for plant-based versus non-plant-based OFBs (CT: p < 0.001; radiography: p = 0.007), small particles (<1.00 mm vs. >1.00 mm; CT: p = 0.001, radiography: p = 0.024), and with eyeball wall locations (vs. intraocular; CT: p < 0.001, radiography: p = 0.021). Similarly, B-scans were less efficient for plant-based and eyeball wall-located OFBs (both p = 0.001), whereas the difference based on dimensions was not significant (p = 0.118).
Conclusions: CT, radiography, and B-scans showed lower detection rates for plant-based, small, and eyeball wall-located OFBs. Our findings strongly suggest that UBM could be a more adequate imaging modality when such OFBs are suspected.
(© 2023 American Association of Physicists in Medicine.)