Corneal chalcosis secondary to a brass bullet casing fragment.

Case report

A 22 year-old male presented to the Mayo Clinic Cornea Service with a 2-month history of a burning sensation in the left eye only when showering. He also noted a change in eye color but no decrease in vision. He related a history approximately 3 years prior of a bullet casing exploding while firing a gun, resulting in a piece of shrapnel embedded in his left cornea. At the time, he was advised not to have the foreign body removed due to its depth in the cornea. On examination, best corrected visual acuity was 20/20. There was intense staining of the deep stroma and Descemet membrane in the area surrounding the shrapnel fragment (Fig. 1, Fig. 2). There was no evidence of intraocular foreign body or staining of other intra-ocular tissues. Given the risk of progressive corneal opacification, removal of the foreign body was recommended. A 2 mm incision, 350 μm in depth was made directly over the foreign body with a diamond blade. Deeper lamellae were bluntly dissected with a Sinskey hook until the foreign body was exposed and removed (Fig. 3). The wound was closed with a single interrupted 11–0 nylon suture. The 0.5 mm foreign body was acid-digested and analyzed by inductively-coupled plasma mass spectrometry (ICP-MS) using the Total Quant method which identified copper and zinc in approximately a 3:1 ratio, respectively, consistent with a brass alloy. The results were confirmed using a triple quadrupole ICP-MS (ICP-MS/MS) method.

Fig. 1

Shrapnel fragment embedded in the inferonasal left cornea with surrounding 3mm diameter area of copper staining.

Fig. 2

Slit lamp photography highlighting the deep location of the solid foreign body and intense copper discoloration of the deep corneal tissue.

Fig. 3

Intraoperative photograph of the excised foreign body.

Discussion

Corneal chalcosis has been observed in cases of copper-containing intraocular foreign bodies and has also been extensively discussed in relation to hypercupremia secondary to Wilson disease, multiple myeloma, and others. In this patient, the deep location of the foreign body resulted in impressive stromal as well as endothelial copper deposition. This case highlights that the process of copper dissolution from a brass foreign body is progressive and may initially be asymptomatic. Indeed, corneal chalcosis has been observed in some cases to be an asymptomatic process for long periods of time. Copper is a component of many metal alloys, including brass and bronze. When there is uncertainty about the composition of a metallic foreign body, it is often the history that may help elicit a potential causative material. The individual elements of the material can then be ascertained through publicly available materials safety data sheets or through the material manufacturer directly. In this easily retrieved foreign body, we demonstrated the usefulness of mass spectrometry to directly analyze the alloy.

Conclusions

This case illustrates an example of delayed corneal chalcosis secondary to a brass bullet casing fragment. No intraocular toxicity was noted, but the resulting intense corneal staining does highlight the concern with prolonged observation of a copper-containing corneal foreign body. In such cases, we recommend removal of the foreign body to prevent eventual loss of visual function due to discoloration of the central cornea.

Patient consent

The patient orally consented to publication of the case.

Funding

Mayo Clinic.

Conflicts of interest

The following authors have no financial disclosures: AS, SE, PJ, KB.

Authorship

All authors attest that they meet the current ICMJE criteria for Authorship.