An intraorbital foreign body (IOrbFB) refers to any foreign material present within the orbit, regardless of whether the eyeball is perforated or penetrated. ICD-10 codes are H05.50–H05.53 (retained foreign body following orbital wound).
Foreign bodies are classified from multiple perspectives.
Approximately 1 in 6 cases of orbital trauma is complicated by IOrbFB6). The overall incidence of traumatic intraocular foreign bodies (IOFB) is reported to be 2.9%5).
A literature review of 33 cases of orbital penetrating trauma caused by large foreign bodies found that the causes were assault 36.3%, falls 33.3%, and traffic accidents 12.1%; 84.85% were male, and the mean age was 27.7 years8). The injured are predominantly working-age males, with metalworking, construction, sports, and agriculture being the main injury situations.
In the literature review, 84.85% were male, with a mean age of 27.7 years8). Assault, falls, and traffic accidents are the main causes of injury. Working-age males in metalworking and construction are high-risk groups.
The causes of injury are diverse.
Metallic Foreign Bodies
Iron and steel: Long-term retention causes ocular siderosis. Visual prognosis requires caution.
Copper: Causes ocular chalcosis. High-purity copper can lead to fulminant panophthalmitis.
Lead and aluminum: Relatively low reactivity; often well tolerated as inorganic metals.
Organic Foreign Bodies
Wood and plant material: Highest risk of infection and inflammation. Can cause orbital cellulitis and extraocular muscle palsy. Surgical removal is recommended in all cases.
Animal-derived material: High infection risk; may require coverage for anaerobic bacteria and fungi.
Nonmetallic Foreign Bodies
Glass and plastic: Relatively well tolerated, similar to metals.
Fiberglass and rubber: Tissue reactions vary; management depends on the size and location of the foreign body.
Organic materials have a high risk of infection and inflammation and can be a source of anaerobic bacteria and fungi. Because of the risk of orbital cellulitis and abscess formation, surgical removal is absolutely indicated. Also, wood can be easily overlooked on CT because it has a density similar to air 6).
Details of the injury mechanism (explosion, gunshot, metal strike → strongly suspect IOFB) and identification of the entry wound are important. Emergency exclusion of open-globe injury and traumatic optic neuropathy should be performed. Evaluation of cranial nerves and a complete ophthalmic and adnexal examination should be carried out.
The characteristics and indications of each imaging modality are shown below.
| Imaging Modality | Indications/Features | Cautions |
|---|---|---|
| CT (first choice) | Can detect small foreign bodies as small as 0.06 mm³ 4). Gold standard. | Wood may resemble air density; be careful not to overlook 6). |
| MRI | Limited use for wooden/organic foreign bodies and tiny fragments when CT is negative. | Only after excluding ferromagnetic metal. |
| Ultrasound (B-mode) | Detection of anterior orbital foreign bodies, retinal detachment, and hemorrhage. | Do not press firmly if open-globe injury is suspected. |
| Plain X-ray | Metal screening | Graphite, plastic, wood are underestimated |
CT details: Non-contrast CT (axial, coronal, sagittal) is the first choice. Search with thin slices of 3 mm or less. 3D CT is useful for understanding the position and shape of foreign bodies, and CT angiography is recommended when near large blood vessels 8). Hounsfield units can distinguish foreign body materials. Waters plain X-ray is used to detect small metals in the orbit.
CT diagnosis of wooden IOFB: Dry wood is easily mistaken for traumatic orbital emphysema. Using bone window width expansion (WL 500 HU, WW 3000 HU) and lung window (WL -500 HU, WW 1500 HU) improves the accuracy of distinguishing wood from air 6). A geometrically shaped, linear low-density area strongly suggests wood 6). Fresh wood shows the same density as vitreous and extraocular muscles, while in the chronic phase it changes to high absorption due to dehydration and surrounding calcification 6).
MRI: Only usable after ferromagnetic metal foreign bodies have been excluded. If metal is present, it is contraindicated because the foreign body may move due to magnetic field changes. Plant foreign bodies may not be visualized when their water content is low.
Culture of the wound or foreign body should be performed for confirmed foreign bodies.
If a ferromagnetic metal foreign body is present, MRI is absolutely contraindicated. The foreign body may move due to magnetic field changes, causing severe injury. Only when metal has been excluded can MRI be used limitedly for evaluation of wooden/organic foreign bodies or small fragments.
The management strategy is determined based on material, size, location, complications (visual function, eye movement, infection), and the surgeon’s expertise.
Conservative Management
Indications: Small, inert, deep metal foreign bodies (inorganic), uncomplicated posterior inorganic foreign bodies.
Rationale: Metal and glass are relatively well tolerated 5). Consider the risk of structural damage from removal.
Note: Regular monitoring for abscess and fistula formation is necessary. Explain to the patient that if ferromagnetic material remains, future MRI will be contraindicated.
Surgical Removal
Absolute indication: All organic foreign bodies (risk of infection/inflammation).
Indications: Neurological deficits, mechanical restriction of eye movement, acute or chronic infection, optic nerve compression4), large foreign bodies8), copper-containing foreign bodies4).
Principle: If globe rupture is present, prioritize globe repair before foreign body search. Basically, promptly remove the foreign body and suture the wound.
The decision depends on the material and presence of complications. For small, inert metal or glass foreign bodies that are asymptomatic and without complications, conservative management may be chosen considering the risk of structural damage from removal. In contrast, organic materials (wood, plant matter) carry a high risk of infection and are indications for removal in all cases. Neurological deficits, restricted eye movement, infection, and copper-containing foreign bodies are also indications for removal.
Siderosis: Iron ionizes to ferrous and ferric forms and diffuses intraocularly. It deposits in the corneal epithelium, iris pigment epithelium, ciliary body epithelium, lens epithelium, retinal pigment epithelium, iris dilator and sphincter muscles, trabecular meshwork, and neurosensory retina, causing tissue damage. This leads to heterochromia iridis, fixed dilated pupil, anterior subcapsular brown deposits, cataract, retinal degeneration, and secondary glaucoma.
Chalcosis: Ionized copper has affinity for basement membranes such as the internal limiting membrane. Chronic course produces Kayser-Fleischer ring (limbal corneal opacity), anterior subcapsular cataract, and greenish deposits under the internal limiting membrane. High-purity copper can cause fulminant panophthalmitis.
This is a rupture of the choroid and retina caused by blunt or high-velocity objects. It presents with bare sclera, vitreous hemorrhage, and intraretinal/subretinal hemorrhage. Retinal detachment usually does not occur due to spontaneous retinal reattachment and scar formation, but 40% of sclopetaria patients require immediate surgery 1).
Motamed Sharati et al. (2024) reported a case of a 15-year-old male who developed chorioretinitis sclopetaria due to an intraorbital metallic foreign body during hammering 1). Uncorrected visual acuity of 10/10 was maintained without ocular penetration. CT images and a management flowchart are presented.
Penetrating thermal injury causing cauterization and shortening of extraocular muscles (similar to tendinoplasty) leads to restrictive strabismus. Extraocular muscles have abundant satellite cells and regenerative capacity, allowing spontaneous recovery 2).
Liebman et al. (2024) reported a case of a 32-year-old female who developed esotropia after a penetrating thermal injury to the left orbit from a hot metal rod 2). After spontaneous improvement over 6 months, medial rectus recession was performed for residual esotropia. Since extraocular muscle thermal injury can recover spontaneously, delaying strabismus surgery may be appropriate.
Foreign bodies can extend into the paranasal sinuses and intracranial cavity through orbital wall fractures (especially the medial wall: the ethmoid bone is the thinnest). In a case of a 28-year-old male motorcycle accident, a brake lever (11 cm) penetrated from the left orbit to the right orbit, complicated by ethmoid fracture and pneumocephalus 4). Such cases require a multidisciplinary approach involving otolaryngology and neurosurgery.
The combination of bone window width expansion algorithm (WL 500 HU, WW 3000 HU) and lung window improves the differentiation accuracy between dry wood and air 6). Dry wood appears similar to air on CT, so it was easily missed with conventional settings.
A minimally invasive approach is possible for foreign bodies extending into the paranasal sinuses. Combined use of intraoperative image-guided navigation is expected to improve identification accuracy for small and fragmented foreign bodies 7).
Lai et al. (2022) reported a case of a boy with a metal ball (15 mm) reaching the posterior ethmoid sinus and sphenoid sinus due to a slingshot injury, which was removed via transnasal endoscopy 7). Visual acuity recovered to 6/9 at 3 weeks postoperatively, demonstrating the effectiveness of a multidisciplinary approach.
Amaral et al. (2023) proposed management guidelines for large foreign bodies based on a literature review of 33 cases, recommending CT in all cases, prompt surgical removal, and strict observation with antibiotic administration for 7 days postoperatively 8).
Damage from the initial trauma accounts for most early complications.
Delayed complications:
| Condition | Prognosis |
|---|---|
| No globe perforation, good visual acuity at presentation, anterior location | Good |
| No globe involvement | No vision loss |
| Postoperative vision loss rate | 2.5–4% |
| Literature review of 33 cases (normal/sequelae/blindness) | 42.4%/16%/36%8) |
Posterior foreign bodies can lead to poor visual prognosis due to optic nerve damage4).
