Ocular siderosis is a clinical condition characterized by deposition of iron molecules in ocular tissue usually caused by retention of an iron-containing intraocular foreign body. Clinical findings include iris heterochromia, pupillary mydriasis, iron deposition on corneal endothelium and anterior lens capsule, cataract formation and retinal pigmentary changes. Patients usually present with a history of ocular trauma, although some may remain asymptomatic and present only later when there is a drop in visual acuity. About 8-10% of all intraocular foreign bodies account for intralenticular foreign bodies and more often than not patients seek medical care for decrease in vision due to cataract. We report a unique case of histopathologically proven lens siderosis in a young man with a preceding history of trauma but no signs of retained intraocular foreign body.
A 32-year-old Indian man presented to the emergency department with 3 days’ history of left eye pain, redness and blurring of vision. He has no past medical history, but gave a preceding uncertain history of foreign body hitting his left eye 6 months ago whilst standing beside a co-worker who was hammering metal. He was given eyedrops by a company doctor and did not seek further treatment even though he continued to have blurring of vision for 3-4 months subsequently.
On examination, his visual acuity was 6/6 in the right eye and hand movement in the left eye. There was no relative afferent pupillary defect and intraocular pressures were normal bilaterally. Examination of the right eye was normal; however, in the left eye, there was a linear cornea scar superiorly and a siderotic white cataract with small breach in the anterior lens capsule. There were brownish orange pigment clumps on the anterior lens capsule suggestive of siderotic cataract clinically [Fig. 1]. There were clumps of white lens matter inferiorly in the anterior chamber but the anterior chamber was otherwise deep and quiet with no signs of a hypopyon. No intraocular foreign body was visualized via slit-lamp examination and gonioscopy. Ultrasound B-scan showed moderately dense mobile vitreous opacities with posterior vitreous detachment, with no retinal tear or detachment. On low gain, no intralenticular foreign body was seen and the posterior capsule was intact [Fig. 2]. Orbital X-ray [Fig. 3] and computed tomography scan [Fig. 4] did not show any retained intraocular foreign body.
Electroretinography examination was deferred at this stage and was decided to remove cataract and implant intraocular lens with intraoperative fundus examination for siderotic changes on the retina. After 1 week of treatment with eyedrops to reduce the anterior chamber inflammation, he underwent an uneventful left cataract aspiration and implantation of posterior chamber intraocular lens under regional anesthesia. Fundus examination was performed intraoperatively and it did not show any retained intraocular foreign body, retinal detachment, retinal tear or vitreous hemorrhage. As there were no siderotic changes on the retina, electrophysiologic examination was not performed in postoperative period as well. Anterior lens capsule was sent for histology, which showed hemosiderin deposits [Fig. 5]. Special stain like Prussian blue was also used to confirm the presence of iron pigments in the anterior capsule. His final visual acuity was 6/7.5 with intraocular lens in situ and stable retina.
Iron is a frequent component of metallic intraocular foreign bodies and may lead to ocular siderosis, which commonly presents as reduced visual acuity. Cataract formation may be an indicator of early siderosis and has been associated with intralenticular foreign bodies.[2–4]
There has been previous report of lens siderosis due to intraocular foreign body missed on imaging such as computed tomography and ultrasonography but later detected perioperatively.
In this case however, there was no intraocular or intralenticular foreign body detected clinically or on imaging, but the patient still developed lens siderosis. As optic nerve and retina were healthy, there was no associated afferent papillary defect. We cannot rule out the possibility of a dislodged or resorbed intraocular foreign body. There may have been a lodged intralenticular foreign body immediately after trauma which got resorbed over time. Nevertheless, this case illustrates the importance of close monitoring of patients with history of trauma or previous penetrating injury to the eye, albeit no intraocular foreign body, as they might develop ocular siderosis at a later stage. In view of sight-threatening complications of siderosis, prompt intervention is indicated to preserve visual acuity and prevent progression of siderosis to involve the posterior segment.
1. Hope-Ross M, Mahon GJ, Johnston PB. Ocular siderosis Eye (Lond). 1993;7:419–25
2. Wu TT, Kung YH, Sheu SJ, Yang CA. Lens siderosis resulting from a tiny missed intralenticular foreign body J Chin Med Assoc. 2009;72:42–4
3. O’Duffy D, Salmon J. Siderosis bulbi resulting from an intralenticular foreign body Am J Ophthalmol. 1999;127:218–9
4. Lee W, Park SY, Park TK, Kim HK, Ohn YH. Mature cataract and lens-induced glaucoma associated with an asymptomatic intralenticular foreign body J Cataract Refract Surg. 2007;33:550–2
Source of Support: Nil.
Conflict of Interest: No.