Wrench appears to be source of metal particles in post-phaco eyes

Metallic foreign particles seen on the iris of eyes after cataract surgery at a hospital in India appear to be from a metallic wrench used to tighten the phacoemulsification needle to the hand piece. The authors of this study reached this conclusion because elements found on the wrench were similar to those of the metal particles found in these eyes.

While they did not see adverse reactions or signs of inflammation in the cases they observed, which were followed regularly, I wonder about the effect on postoperative inflammation of metallic foreign particles appearing on the iris after phacoemulsification.

One case report has described a metallic foreign body on the iris surface that resulted in chronic recalcitrant postoperative inflammation. The authors of the current study therefore state the appearance of foreign bodies that do not cause inflammation cannot be neglected and such complications must be prevented in the future.

Their study was a case series of 11 eyes in which metallic foreign particles were observed on the iris surface and the pupillary border on the first postoperative visit after phacoemulsification.

One metallic particle, which was stuck to the iris surface, was removed intraoperatively and sent for metal analysis along with the phaco needle, the wrench used to tighten the phaco needle to the phaco hand piece, and the anterior chamber maintainer used during phacoemulsification. The composition of the elements was studied by scanning electron microscopy (SEM) to determine the origin of the metallic particle.

On SEM, three elements (carbon, magnesium and silicone) were common in the metal particle and four elements (carbon, magnesium, silicone and titanium) on the wrench. The elements in the phaco needle (titanium) and anterior chamber maintainer (manganese, iron, and nickel) did not match those in the metal particle.

At the hospital where the study was conducted, the metallic wrenches were replaced by plastic ones. Since then, no metallic particles have been encountered intraocularly after phacoemulsification.

The authors conclude that in order to prevent the occurrence of metallic particles in the eye and complications caused by them, after using the metallic wrench to tighten the phaco needle, the phaco needle and the phaco hand piece should always be thoroughly checked for metallic fragments on the surface that could have shred from the irregular surfaces of the wrench. They also propose the alternative of using plastic wrenches.