The Rusty Eye: Ocular Siderosis Masquerading as Chronic Anterior Uveitis

Ocular siderosis (OS) is a progressive, vision-threatening condition caused by a retained, iron-containing intraocular foreign body (IOFB). It can be easily mistaken for chronic anterior uveitis, especially in the absence of a clear history of prior ocular trauma. This diagnostic pitfall can delay appropriate management, worsening the visual prognosis. A healthy 43-year-old man presented with recurrent redness, photosensitivity, and progressive blurred vision in the left eye, of one-year duration, worsening over the past three months. He was initially diagnosed with chronic anterior uveitis with elevated intraocular pressure, and commenced on topical steroids, cycloplegics, and antiglaucoma eyedrops. Examination revealed a mid-dilated, non-reactive pupil, with diffuse brown deposition over the corneal endothelium and anterior capsule of the lens. A subsequent follow-up visit revealed minimal improvement. Further questioning revealed a history of trauma two years prior, which was only self-treated with over-the-counter eyedrops. Siderosis bulbi was highly suspected in view of the mechanism of injury and the insidious onset of poor vision. Computed tomography of the orbit showed the presence of a well-defined hyperdense foreign body, producing streak artifacts near the vitreous base. The left eye recovered well after removal of the IOFB, with visual acuity improving to 6/15 three months postoperatively. This case underscores the importance of considering OS in patients with atypical or refractory anterior uveitis, especially in the context of overlooked trauma. Early radiological evaluation for the localization of the retained IOFB and timely surgical intervention can lead to an excellent visual outcome.