An intraocular foreign body composed of iron can result in siderosis. The iron ions are absorbed intracellularly, resulting in epithelial toxicity. If the foreign body is not removed there will eventually be severe deterioration of visual function.


Anatomic Site

Clinical Finding in Siderosis


normal or diffuse brown haze


rusty brown discoloration in the affected eye


diffuse brownish discoloration of the anterior capsule; cortex appears yellow; a cataract may develop

vitreous fluid

brownish discoloration with opacification


epithelial degeneration affects peripheral fundus first, then posterior segment


Other features:

(1) The deposits are attracted to a magnet, which can aid in removal.

(2) The electroretinogram (ERG) initially shows a supernormal b-wave. Over time there is a 100% loss in amplitudes. Tacking the changes over time is useful for monitoring retained iron bodies.

(3) Secondary glaucoma may develop late.


Prognosis is affected by:

(1) whether the foreign body is removed

(2) ferrous state (more toxic than ferric)

(3) vitreous opacities

(4) diffuse cataract

(5) retinal toxicity

(6) secondary glaucoma


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