Ocular foreign body

An ocular foreign body occurs when an orbital foreign body intrudes into the globe itself, often threatening vision, and requiring urgent surgical removal.

Clinical presentation

Patients present in a highly variable manner based on the precise intraocular location and properties of the foreign body, as well as the presence of any associated trauma. Common symptoms include:

• tearing
• decreased visual acuity
• photophobia
• a "foreign body" sensation

Radiographic features

Ultrasound

Available at the point-of-care as a screening tool, many foreign bodies may be accurately identified with ocular ultrasound. While sonographic findings differ based on the nature of the foreign body, common features include ²:

• abnormal echogenic structure with posterior acoustic shadowing
  • may demonstrate a twinkling artifact on color flow Doppler ¹
  • reverberation artifacts are common
• vitreous hemorrhage is commonly present
• may demonstrate location-dependent mobility
  • a vitreous foreign body is more likely to be mobile than one in the posterior orbital fat
• other associated injuries may include:
  • globe rupture
  • retinal detachment
  • choroidal detachment

CT

A CT orbits is the examination of choice, as it provides superior localization of small foreign bodies, the anatomy of the surrounding structures, and any associated injuries. Unlike MRI, it may be used in the detection of a metallic foreign body ³.