On the recovery of the electroretinogram of rats after removal of intravitreal lead particles

Eye injuries with metal missiles presenting to an emergency center: a three year study

The authors retrospectively evaluated 33 eye injuries due to metal missiles in 31 patients presenting to our emergency center over the last 3 years. Injuries occurred most frequently when the patients were grinding metal or working on their cars. The type of metal involved in the injury often dictates the type of ophthalmic reaction that will occur. A discussion of intraocular metallic foreign bodies with an emphasis on electroretinograms and metal analysis is presented.

Surface area sized of intravitreal iron wires: their effects on the electroretinograms of rats

The electroretinogram (ERG) was recorded 20 times over a period of 360 days in 26 albino-rats with implanted intravitreal iron wires ranging in size between 0.15 and 1.2 mm2.

RESULTS

(i) The a- and b-wave amplitudes decreased rapidly within one day after iron wire implantation. During the following week the amplitudes recovered to some extent. In the course of the next few months the a- and b-wave amplitudes of the eyes implanted with the largest iron wires (1.2 mm2) decreased steadily to about 20% by the end of the observation time, whereas in the groups containing smaller iron wires the electroretinographic changes were limited. (ii) Implantation of equally-sized glass splinters reduced the a- and b-wave amplitudes to 65-75% in comparison to the intact fellow eye. Fast recovery of both potentials to 83-93% followed within two weeks. The mean values of the a-wave amplitudes reached nearly 100%, those of the b-wave 90-95% in the next month.

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

The influence of intravitreal zinc particles (1.3 mm2) in the eyes of rats caused the amplitudes of the electroretinogram to decrease to about 50% of the initial values within 24 hours, whereas the prolongation of the peak times began only on the third day after particle implantation. The removal of the zinc particles after 30 days led to only partial recovery of the amplitudes, whereas the peak times reached normal values. Dissociated behaviour of the amplitudes and peak times as described here was not found in earlier experiments with intravitreal iron, copper or lead particles of the same size. The extraction of intravitreal zinc particles (1.3 mm2) one day after implantation resulted in a recovery of the amplitudes up to 85%.

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%.

On the recovery of the electroretinogram of rats after removal of intravitreal lead particles

Lead particles (1.4 mm2) were implanted into the vitreous body of rats (16 animals) for 10 days and the recovery rate of the ERG was measured over an observation time of 190 days. After extraction of the lead particles the a- and b-wave amplitudes show a recovery from about 60% to 87% in comparison to those of the intact fellow eyes between the 60th and 90th day of observation. In earlier experiments the mechanical damage was measured using glass splinters. The differences between these values and the above mentioned recovery rate after lead extraction correspond to the irreversible component of the metal intoxication. In another group of rats (16 animals) the lead particle was not removed before the end of the observation time of 190 days. Subtracting these ERG values from those of the first group of rats after lead extraction one gets small differences which correspond to the reversible component of the metal intoxication. The irreversible lead intoxication is much less than that of intravitreal iron particles as we found under the same conditions. The lead particles we used, are larger than those we have to handle in clinical cases taking the relation of surface area size of the particle to the total bulbus weight. The ophthalmoscopical findings are described.