Experimental siderosis in the rabbit: correlation between electroretinography and histopathology.

An iron foreign body was placed into the vitreous cavity of 22 rabbits' eyes. The electroretinographic (ERG) changes over a-15-week period were recorded. These changes were compared to those in a group of 12 normal rabbits and a group of 5 animals in whom a sham operation was performed. Twelve eyes were enucleated during this period and examined histopathologically. Histopathologic and functional changes in siderosis were both progressive in time, but the ERG values were more consistent among the 22 animals than the morphologic changes. Iron oxidation (Fe0 leads to Fe2 leads to Fe3) was found and suggested to be the mediating factor of the direct iron cytotoxic effect on the retina.