Neglected Metallic Foreign Body, Complicated By Corneal Siderosis.

Ocular trauma is the leading cause of vision loss in subjects under 40 years old. Eye accidents at work are worrying because of their frequency and their potential seriousness, especially in the presence of an intraocular foreign body in young subjects in full professional activity.

Ocular trauma by a metallic foreign body (MFB) in the workplace is a frequent reason for ophthalmological consultation in emergencies and a cause of work accidents involving the functional and anatomical prognosis of the affected eye.

Ocular trauma by the projection of a metal FB, constitutes - in the absence of wearing personal protective equipment - a frequent cause of work accidents in our environment, especially among welders.

A 35-year-old patient (welder by profession), consulted for a visual acuity decrease in his right eye for 3 months, associated with tearing and photophobia without pain or ocular redness.

ophthalmological examination finds in the right eye: 

A BCVA of 20/30,

A para-central and nasal corneal opacity (in the shape of a cockade), surrounded by a ring of siderosis pigments, with metallic debris in the center suspecting an old and degraded metallic FB. 

The rest of the examination was unremarkable

The diagnosis of an old trauma of the right eye by the projection of a metallic foreign body, neglected and complicated by a ring of corneal siderosis was made.

The ophthalmological examination is completed by an orbital CT, which finds neither an intraocular nor an intra-orbital foreign body.

The extraction of the degraded particles from the MFB was carried out and a topical treatment based on preventive antibiotic therapy and corneal healing agents was prescribed. The patient then calls for regular monitoring and awareness raising on the importance of prevention by wearing personal protective equipment.

FB is subject to various attacks of varying severity and it manifests itself by inflammatory, infectious, or toxic phenomena depending on the nature of the FB.

The complete picture of ocular siderosis includes: corneal involvement with deep ring of rust, iris heterochromia, poorly reactive pupil in semi-mydriasis due to involvement of the iris sphincter and dilator, the presence of rust-colored spots on the anterior capsule of the lens, then a cataract, retinal pigmentary degeneration beginning in the periphery, with centripetal progression, vitreous remodeling and high ocular tension by ferric infiltration of the trabecular meshwork.

The ERG makes it possible to make the diagnosis of ocular siderosis and to quantify the degree of retinal felicity, after having confirmed the presence of a FB on the CT scan.

Orbital CT is an essential paraclinical examination in search of an unrecognized intraocular and/or intraorbital localization. It can highlight a FB if its size exceeds 0.3 mm.

Negligence and failure to extract metallic FBs are responsible for ocular siderosis, the prognosis of which remains poor if the FB is quickly removed, followed by topical treatment and regular follow-up.

We draw attention to the importance of prevention in the workplace by wearing personal protective equipment, and to the emergency management of metallic FBs in order to avoid ocular siderosis.