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A Metallic Foreign Body Presenting in the Anterior Chamber Angle

Davidson, Richard S. M.D.; Sivalingam, Arunan M.D.

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Purpose. This article describes a case in which a patient presented with a previously undetected metallic foreign body in the anterior chamber angle.

Methods and Results. A 42-year-old Hispanic man presented with a 5-day history of foreign-body sensation and redness in his left eye. He had been using a hand saw without safety glasses 2 days before the onset of his initial symptoms. Physical examination revealed a metallic foreign body embedded in the inferior angle of his left eye. Surgical removal of the foreign body was performed, and the patient remains well 1 year after surgery.

Conclusions. All physicians should maintain a high degree of clinical suspicion for intraocular foreign bodies when presented with a patient who may have sustained ocular trauma. All eye-care providers need to emphasize the need for proper eye protection to patients who engage in high risk activities that may lead to penetrating ocular trauma.

From the Wills Eye Hospital, Philadelphia, Pennsylvania.

Accepted May 25, 2001.

Address correspondence and reprint requests to Dr. Richard S. Davidson, 5050 Brand Way, Sacramento, CA 95819.

In the spectrum of ocular trauma, intraocular foreign bodies represent a potentially vision-threatening entity. The extent of injury often depends on four factors: the size and composition of the foreign body; the force at which the foreign body enters the eye; the location of the entrance wound; and the final resting place of the foreign body. 1 The inflammatory response may be immediate or delayed. Steel is one of the most common foreign bodies, resulting, usually, from metal-on-metal injuries. In most cases, the entrance wound and intraocular foreign body are easily detected. Occasionally, however, the area of penetration may not be obvious, prompting the clinician to use other diagnostic approaches to determine the extent of the injury. One circumstance is when the foreign body lodges in the inferior anterior chamber angle, making it virtually impossible to detect without gonioscopic examination and a high degree of clinical suspicion.

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CASE REPORT

A 42-year-old Hispanic man presented to the Wills Eye Hospital emergency department complaining of irritation of his left eye. He stated that 5 days before presentation he was using a hand saw when he noticed a piece of metal fly up and hit him in his left eye. He was not wearing safety glasses at the time. Two days later, he began to experience mild foreign body sensation in his left eye and he noticed that his eye was slightly red. He was seen by his family physician and was diagnosed with conjunctivitis. He did not start on any medications at that time. Three days later, because he was not getting better, he was seen by an ophthalmologist, who suspected an intraocular foreign body but could not find it. The patient then decided to come to the Wills Eye Hospital emergency department for further evaluation.

On initial examination, the patient’s visual acuity was 20/20 OD and 20/25 OS. Both eyes were pharmacologically dilated, and motility and confrontation visual fields were within normal limits, OU. A slitlamp examination showed the right eye was within normal limits. A small pterygium was present nasally in his left eye. His cornea in the left eye did not have an epithelial defect but a full-thickness wound appeared beneath the epithelium (Figs. 1 and 2) measuring approximately 1 mm in vertical length, paracentrally near the 9-o’clock position. The wound was Seidel-negative, and the remainder of his cornea was clear. The conjunctiva was 1 to 2+ injected, and the anterior chamber was deep, with 1+ cell and flare. The iris appeared round and regular, with no evidence of rubeosis or heterochromia. The anterior lens capsule showed a small paracentral disruption near the 12 o’clock position, but no cataract was present (Fig. 3). The anterior vitreous was clear, and the patient’s fundus examination showed a normal macula, disc, vessels, and periphery, OU. Gonioscopic evaluation of the left eye revealed a metallic foreign body embedded in the inferior angle (Figs. 4 and 5).

FIG. 1

FIG. 1

FIG. 2

FIG. 2

FIG. 3

FIG. 3

FIG. 4

FIG. 4

FIG. 5

FIG. 5

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RESULTS

A computed tomography (CT) examination of the orbits confirmed the presence of the foreign body and showed no sign of other foreign bodies. The patient was discharged with a prescription of tobramycin drops four times per day, scopolamine drops 0.25% once per day, and ciprofloxacin 500 mg orally twice per day. He was instructed to return to the cornea department in 2 to 3 days so that further testing could be performed to aid in his management.

At follow up, the patient’s clinical condition was unchanged. Ultrasound biomicroscopic examination demonstrated the foreign body embedded in the peripheral iris and ciliary body of the left eye (Fig. 6). At that time, surgery was scheduled for removal of the foreign body. Six days after his initial presentation at Wills Eye Hospital (11 days after the injury), the patient underwent surgery for removal of the intraocular foreign body. A clear corneal incision was made at the 12-o’clock position. Viscoelastic material was instilled into the anterior chamber. An intraocular magnet was advanced into the inferior angle, the foreign body immediately adhered to the magnet and was carefully removed from the eye.

FIG. 6

FIG. 6

Postoperatively, the patient has done well. One year after surgery, his visual acuity remains 20/20 OU, and he has no signs of a traumatic cataract and no evidence of infection.

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DISCUSSION

Few cases of intraocular foreign bodies presenting in the anterior chamber angle have been reported. In this case, the foreign body appeared to have entered through the cornea, hit the anterior lens capsule and then “fell” into the inferior angle, making it difficult to detect on initial examination. Therefore, intraocular foreign bodies should be suspected and ruled out after any ocular or orbital trauma. It is imperative that all physicians obtain a detailed history, with appropriate questions regarding exposure to metal-on-metal contact or other high-risk actions. A complete ocular examination, including gonioscopy (as long as there is no risk of extrusion of intraocular contents), should be performed. Finally, the proper imaging studies should be performed to aid in the diagnosis and to make sure no other intraocular foreign bodies are present. Standard imaging should include a CT scan—keeping in mind that magnetic resonance imaging is contraindicated because the foreign body may be metallic. Deramo et al demonstrated the value of ultrasound biomicroscopy (UBM) in localizing and determining the extent of foreign body penetration in the anterior segment. Therefore, UBM can be a useful adjunct for managing the patient. 2

It is not uncommon for an intraocular foreign body to masquerade as a uveal melanoma, chronic mydriasis, an iris nodule, or idiopathic chronic iridocyclitis. 3,4,5 For patients who present with one of these entities but do not improve with traditional therapy, it is best to obtain a more detailed history for possible trauma, and to perform the proper studies to rule out an intraocular foreign body.

Surgical management of intraocular foreign bodies depends on localizing and visualizing the foreign body and determining whether it is encapsulated. Additionally, whether or not the intraocular foreign body is magnetic will also play a role. Arora et al demonstrated that the timing and necessity of foreign body removal may be adjusted according to the characteristics and associated ocular trauma. 6 Chow et al also showed no statistically significant difference with regard to visual outcome when comparing the use of an internal or external (external magnet) approach to metallic foreign body removal. 7 Greven et al demonstrated that the patient’s presenting visual acuity was the strongest predictor of final visual outcome. Prognostic factors for improved visual outcome also included hammering metal on metal as the mechanism of injury. Predictors of poor outcome included a poor presenting visual acuity, the presence of an afferent papillary defect, and vitreous hemorrhage. 1

Infectious endophthalmitis is a rare but potentially vision-threatening consequence of trauma involving an intraocular foreign body. Most study series cite an endophthalmitis incidence between 4.7% and 13.3%, depending on the study. In a large study for the National Eye Trauma System, Thompson et al showed that removal of in intraocular foreign body within 24 hours of injury markedly reduces the risk of endophthalmitis developing. When surgical repair was delayed, the authors found that older persons (over 50 years old) were at higher risk for developing endophthalmitis. The composition of the foreign body had no significant effect on the risk of developing endophthalmitis. Most notable was the fact that no protective eyewear was being used by 434 (94%) of the 463 persons who experienced intraocular foreign bodies. 8

Our case demonstrates the need for a thorough history and physical examination when examining a patient who sustains ocular trauma. In addition, proper diagnostic tests, including gonioscopy, should be used to aid in the diagnosis and management of the patient. Finally, this case underscores our need as eye-care providers to educate all of our patients in the use of protective eye wear so that the incidence of these potentially devastating eye disorders can be reduced.

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REFERENCES

1. Greven, CM, Engelbrecht, NE, Slusher MM, et al. Intraocular foreign bodies: Management, prognostic factors, and visual outcomes. Ophthalmology 2000 March; 107(3): 608–612.
2. Deramo, VA, Shah, GK, Baumal, CR, et al. Ultrasound biomicroscopy as a tool for detecting and localizing occult foreign bodies after ocular trauma. Ophthalmology 1999 February; 106(2): 301–305.
3. Cunliffe, I, Singh, A, Mody, C, et al. Retained intraocular foreign body simulating choroidal melanoma. German Journal of Ophthalmology 1993; 2: 416–418.
4. Monteiro, ML, Coppeto, JR, Milani, JA. Iron Mydriasis: Pupillary paresis from occult intraocular foreign body. Journal of Clinical Neuro-ophthalmology 1993; 13(4): 254–257.
5. Alexandrakis, G, Balachander, R, Chaudhry, N, et al. An Intraocular foreign body masquerading as idiopathic chronic iridocyclitis. Ophthalmic Surgery and Lasers 1998 April; 29(4): 336–337.
6. Arora R, Sanga L, Kumar, M, et al. Intralenticular foreign bodies: Report of eight cases and review of management. Indian Journal of Ophthalmology. 2000 Jun; 48(2): 119–122.
7. Chow, DR, Garretson, BR, Kuczynski, B, et al. External versus internal approach to the removal of metallic intraocular foreign bodies. Retina 2000; 20(4): 364–369.
8. Thompson, JT, Parver, LM, Enger, CL, et al. Infectious endophthalmitis after penetrating injuries with retained intraocular foreign bodies. Ophthalmology 1993; 100: 1468–1474.
Keywords:

Intraocular foreign body; Anterior chamber angle; Ocular trauma; Ultrasound biomicroscopy; Endophthalmitis

© 2002 The Contact Lens Association of Ophthalmologists, Inc.