The ERG and ophthalmological changes in experimental metallosis in the rabbit. II. Effects of steel, copper and aluminium particles

On the recovery of the electroretinogram after removal of intravitreal copper particles

This report details the influence of the time lapse and surface area size of intravitreal copper foreign bodies on the electroretinogram (ERG) and the recovery of the potentials after removal of the particles. Pure copper wires were implanted temporarily into the vitreous body of rat eyes in the area of the ora serrata and the values of the ERG were compared with those of the intact fellow eyes. In three different procedures with groups of 12 animals each the following results were obtained: (1) The metal toxicity of small copper particles (0.3 mm2) remaining one day in the vitreous body reduced the amplitudes of the a1-, a2-, and b-wave only 10% by the end of the observation time of 260 days, (2) The loss of ERG amplitudes increased to about 25% under the influence of larger copper particles (1.3 mm2; time lapse one day); and (3) Copper particles with an active surface of 1.3 mm2 remaining two days in the vitreous body caused a permanent loss of about 50%.

Histochemical localization of intraocular copper foreign bodies

Alizarin blue, rhodanine, and rubeanic acid stains cytochemically localized copper in rabbit eyes harboring intravitreal copper foreign bodies of varying copper composition. Local deposition presented in small amounts in areas adjacent to the foreign body (fibrous capsule, adjacent retina, and surrounding macrophages). The localized pattern was more frequent with the 60% copper alloy, when the foreign body was encapsulated or shiny, and when the aqueous copper concentration was normal. The generalized pattern of copper deposition revealed moderate to marked amounts of copper within the following multiple intraocular structures: (1) the posterior cortex of the lens, (2) the vitreous cavity, either in free-floating macrophages or in macrophages on the surface of the retina, (3) the retina, either within monocytic macrophages, Müller cells, or extracellularly in granular clumps, and (4) the fibrous capsule around the foreign body. Copper in several eyes was observed within macrophages that were clustered around the central retinal vessels within the optic nerve. The generalized pattern was frequent with the pure copper foreign body, when the copper foreign body was tarnished, and when copper concentration of the aqueous humor was elevated. There was a direct toxic effect of copper on the lens in the form of local opacification in the posterior cortex but no clinical or histochemical evidence of a Kayser-Fleisher ring or a sunflower cataract.