Contents
Chronic degenerative process induced by chemical reactions between ocular tissues and iron particles from retained iron-containing intraocular foreign bodies (IOFBs).
History:
In 1890, Bunge described a series of ocular changes that occurred as a consequence of a ferrous IOFB, which he termed siderosis. Although quite common in the past and well described in textbooks, most of the literature is from the pre-vitrectomy era.
Pathophysiology
This sight-threatening condition is caused by the presence of an iron containing IOFB that degrades and has an affinity for epithelial surfaces, therefore affecting virtually all ocular tissues: iris, ciliary non-pigmented epithelium, lens and retinal pigment epithelium.
Clinical features
- Decreased visual acuity (M/C presentation)
- Cataract (#2 M/C)
- Retinal pigmentary degeneration
- Iris heterochromia
- Pupillary mydriasis
- Secondary glaucoma
- Relative afferent pupillary defect (RAPD)
- Retinal detachment
Diagnosis
Relative afferent pupillary defect (RAPD):
Direct pupillary light reaction and the accompanying consensual reaction of the opposite pupil are weaker on illumination of the affected eye than on illumination of the unaffected eye due to unilateral or asymmetrical disease of the retina or optic nerve
Plain orbital X-ray:
First-line imaging modality for detection of an IOF
CT scan:
Gold standard for IOFB detection
Management
Removal of IOFB can stop the progression of siderosis.