Purpose: To assist clinicians in the diagnosis and management of ocula
r siderosis. Methods: The diagnosis and management of three cases of o
cular siderosis secondary to a retained iron-containing intraocular fo
reign body are described. Results: Noteworthy features included: 1) th
e characteristic features of a tonic or Adies pupil (one case) and 2)
the failure of high-resolution computed tomography scanning and plain
film radiography to detect the intraocular foreign body (two of three
cases). In contrast, ultrasonography demonstrated the intraocular fore
ign bodies in all cases and accurately localized them to the inferior
retinal quadrants. A third noteworthy finding was that a preoperative
electroretinogram reduction in amplitudes of as much as 40% compared w
ith that of the uninvolved eye was compatible with excellent vision, a
nd that the electroretinogram returned to normal after the intraocular
foreign body was removed. Conclusions: Ocular siderosis should be con
sidered in the differential diagnosis of a tonic or Adies pupil. To de
tect an occult intraocular foreign body, clinicians should not rely ex
clusively on computed tomography scanning or plain film radiography, b
ut should also use B-mode echography with careful study of the inferio
r quadrants. In ocular siderosis a preoperative electroretinogram redu
ction in amplitudes of as much as 40% may be reversible after intraocu
lar foreign body removal.